Bio Pellets vs Sulphur Denitrator

[CoryDude]

Thought maybe we could discuss the differences between the two nitrate reduction methods. Pros and cons are welcome. Let's keep it civil. What's always good for the goose isn't always good for the gander.

I've run a denitrator for a while now. So here's my thoughts on them.

Good
1) I've used the same sulphur media for almost 5 years with only periodically rinsing the media a couple of times a year.
2) Cuts down on my water changes by at least half.
3) Reliable filtration that is based on anaerobic bacteria. Not much to do other than to ensure you keep the oxygen levels low in the reactor.
4) Is based in the principal that anaerobic bacteria begin to strip oxygen molecules from anything including NO3, with the only byproduct being nitrogen.
5) Is great for low to medium bioload tanks.
6) kinda of cool when you see water with nitrates going in at 40 meq/L and coming out at zero.

Bad
1) constant maintenance like a calcium reactor. If your effluent slows, you run the risk of introducing hydrogen sulphide into the tank. I've honestly had this happen many times before with no ill effects. Sure it makes your tank stink for a while, but I have yet to lose anything yet because of this.
2) Effluent...which means you only clean your water 1 drip at a time. But as you build up bacteria populations in your reactor, and the no3 levels drop in your tank, this pace picks up.
3) Extremely easy to crash your bacteria culture if you increase your effluent drip rate too fast. No worries, you'll be back up and running in a week or so.
4) Only consumes oxygen, so no reduction of nitrogen products in the nitrogen cycle. This means you can still have algae issues if you have excessive organics in your tank. Also, no reduction in phosphates like you see with bio pellets.

Anyways, that's my .02.

[FireWater]

Cory, may I add another method to the mix? I've heard vinegar mentioned, similar to the old vodka method. I've been trying to research and read up on it. I plan to maybe, possibly, might look into adding a drip method on the 120g.

[Big_Pun]

ive been a bio pellet fan boy for a few years. Yes they reduce nitrates down to zero, easy to set up in a reactor, only need to be topped off and not replaced(as they dissolve) set up is easy, just a reactor and pump needed.
One thing is you need to make sure you use the correct amount and if starting them up in a older established tank you will need to start half dose as it can cause a bio bloom. They also take a lil time to work 4-8 weeks. ive also noticed on some older tanks cycano will creep in upon start up but usually goes away after they start working. The tumble needs to monitored and cannot stop or they clump and cause nutrient problems. i have not seen a significant reduction in phosphates with them and still use GFO.
some things i like to do is use a probiotic with them to start them up and shut off skimmer for a few days and remove carbon and gfo. as part of my maintenance i like using dr tims eco balance and waste away to keep beneficial bio load up this keeps cyano away.

[rrasco]

BioPellets, vodka, vinegar and sugar are all forms of organic carbon dosing. The intended purpose of providing an organic carbon source is to establish and sustain the colonization of probiotic bacteria which "consume" inorganic nitrogen and phosphate and perform as an additional form of nutrient export. Probiotic bacterial strains can be introduced into a closed system via commercially available products to speed up and diversify their colonization.

[Sherita]

Following along on this. Really want to hear more about the use of a denitrator, since it's something I've been seriously thinking about. Cory, did you make yours, or buy it?

[grouch]

I mix vinegar with kalk for my dosing. Vineger gives me the carbon for bacterial growth to reduce nitrate and causes an increase in C02 so I don't percipitate calcium out of my tank. The vineger also disolves the kalk in acid rather than water causing 30% more calcium to be present in a calcium acetate solution. Been doing it about a year now with no ill effects. Here's a good write up on it I found.

http://www.reefscapes.net/articles/breefcase/kalkwasser.html




Cory, may I add another method to the mix? I've heard vinegar mentioned, similar to the old vodka method. I've been trying to research and read up on it. I plan to maybe, possibly, might look into adding a drip method on the 120g.

[rrasco]

I mix vinegar with kalk for my dosing. Vineger gives me the carbon for bacterial growth to reduce nitrate and causes an increase in C02 so I don't percipitate calcium out of my tank. The vineger also disolves the kalk in acid rather than water causing 30% more calcium to be present in a calcium acetate solution. Been doing it about a year now with no ill effects. Here's a good write up on it I found.

http://www.reefscapes.net/articles/breefcase/kalkwasser.html



Adding vinegar also increases the saturation level of kalk. Normally, saturated kalkwasser is 2 tsp/gallon but adding vinegar increases this level.

[CoryDude]

Probiotic bacterial strains can be introduced into a closed system via commercially available products to speed up and diversify their colonization.

Yep, and I still use prodibio biodigest to help export some nutrients as well. But the reason I love the anaerobic process is that it doesn't rely on the skimmer.


Following along on this. Really want to hear more about the use of a denitrator, since it's something I've been seriously thinking about. Cory, did you make yours, or buy it?

Ive bought a korallin unit back in 2009 and then tried my hand at building my own using a converted mk1 reactor. Just about any calcium reactor could be converted to a denitrator. The key is to use aquamedic's sulphur pearls as the media. The Caribsea stuff is cheaper, but it tends to clump up and restrict the re circulation within the reactor. The sulphur pearls allow for better flow within the reactor. Pm me sometime if you ever want to chat it up. I'm not an expert, but I have a few years under my belt using them.


Cory, may I add another method to the mix? I've heard vinegar mentioned, similar to the old vodka method. I've been trying to research and read up on it. I plan to maybe, possibly, might look into adding a drip method on the 120g.

Sure, the more methods the merrier. I used it more for the reason Tim outlined, for supersaturated calcium. Would you set it up to dose?

[degrijze]

Thought maybe we could discuss the differences between the two nitrate reduction methods. Pros and cons are welcome. Let's keep it civil. What's always good for the goose isn't always good for the gander.

I've run a denitrator for a while now. So here's my thoughts on them.

Good
1) I've used the same sulphur media for almost 5 years with only periodically rinsing the media a couple of times a year.
2) Cuts down on my water changes by at least half.
3) Reliable filtration that is based on anaerobic bacteria. Not much to do other than to ensure you keep the oxygen levels low in the reactor.
4) Is based in the principal that anaerobic bacteria begin to strip oxygen molecules from anything including NO3, with the only byproduct being nitrogen.
5) Is great for low to medium bioload tanks.
6) kinda of cool when you see water with nitrates going in at 40 meq/L and coming out at zero.

Bad
1) constant maintenance like a calcium reactor. If your effluent slows, you run the risk of introducing hydrogen sulphide into the tank. I've honestly had this happen many times before with no ill effects. Sure it makes your tank stink for a while, but I have yet to lose anything yet because of this.
2) Effluent...which means you only clean your water 1 drip at a time. But as you build up bacteria populations in your reactor, and the no3 levels drop in your tank, this pace picks up.
3) Extremely easy to crash your bacteria culture if you increase your effluent drip rate too fast. No worries, you'll be back up and running in a week or so.
4) Only consumes oxygen, so no reduction of nitrogen products in the nitrogen cycle. This means you can still have algae issues if you have excessive organics in your tank. Also, no reduction in phosphates like you see with bio pellets.

Anyways, that's my .02.

Hello, I am new here and I registered myself because I am interested in all information about BADES ( Biological Autothrobe Denitrifaction using Elemental Sulphur)
Reading this I do not recognize a sulphur denitrator system. Let start with the "BAD"
1) Used as part of the system we have to adjust the flow about once a month because each month we take measurements and then we adjust when necessary. Calcium carbonate is added when +-1/10 is consumed and the lime media is washed to remove the bio-film about every 3 months. We use different reactors for lime and sulphur. We had H2S issues twice due to mismanagement of a to small reactor years ago.
2) The flow at low nitrate levels is normally between 2l/h and 3l/h for each litre of Sulphur used.. for a 4000l system this is between 80L/h and 120l/h or +- 2400l/day. Flow depends on the daily to remove quantity of produced nitrate. A 1% reactor can bring down the nitrate level from 50ppm to 1ppm and below easily and keep it there at high daily nitrate production.
3) Used on an established aquarium a new reactor is active after one day and must be corrected after 3 or 4 days. Full operational within 2 weeks. This is a big difference compared with a carbon based denitrator. A sulphur denitrator becomes active when oxygen levels below 3ppm are reached. Carbon based reactors need a far lower oxygen level to become active. The system has crashed twice, years ago, due to mismanagement and the use of a to small reactor.
4) We keep our nitrate level between 1 and 2 ppm because we believe a elevated nitrate level helps calcification but we can easily bring them down to less than 1ppm and this with a daily production op 1ppm or more. This is not possible using a carbon based reactor.
The unit removes phosphate but not all.

Conlusion: there is a lot of difference between our experience and yours.

I do not agree with point 5 of the "GOODS": a sulphur denitrator works very good as problem solver and to reduce high levels of nitrate to the desired level. That is when the reactor is big enough. In most cases the reactor used is to small to bring down the level which makes it vulnerable for mismanagement. When level decreases flow has to be increased. When the reactor is to small the point will be reached where the daily produced quantity of nitrate can not be removed any more. At a level of 30ppm one needs a flow of 10l daily to remove 300mg nitrate daily. At a level of 1ppm we need a flow of 300l daily to remove the same amount of 300mg. The reactor must be big enough to reduce the entered quantity of oxygen when flow is increased. A sulphur denitrator can handle high daily nitrate productions at very low nitrate levels because it can function at high flow.. A sulphur denitrator can be managed in a way one has complete control over the nitrate level and keep the desired level at for example +- 1ppm. To reduce the level from 2ppm to 1ppm the flow true the reactor must be doubled to be able to remove the same daily nitrate production. This is very difficult to manage with a carbon based reactor. Most nitrate-reducing and -removing methods do what they have to do, reduce nitrate, but they give no control over the nitrate level in the system and are difficult to manage.

As the difference in experiences with a sulphur denitrator are what they are I would like to know the volume of sulfur you use in your denitrator and the total volume of the aquarium system connected to it.
I also noted that the in-fluent water has a nitrate level of 40meq/l. That is a lot. Is this correct?

[degrijze]

The main difference between both methods is that the use of a sulfur denitrator makes it possible to have control over the nitrate level in the system and that this level can be managed. Other methods are able to reduce nitrate but the reduction is not or difficult to manage as desired.

[Reefnub]

They make recirculating bio pellet reactors with a control valve which lets you adjust how much nitrate is being eliminated. So I would say that it controllable and not difficult.

[degrijze]

They make recirculating bio pellet reactors with a control valve which lets you adjust how much nitrate is being eliminated. So I would say that it controllable and not difficult.

What you mean is you have some control over the flow true the Creactor to keep the reactor anaerobic. What I mean is having control over the nitrate level in the system. When the nitrate level in the system decreases the flow must increase to make it possible to reduce the same quantity of nitrate daily.
One has 40ppm of nitrate in the system which must be reduced to 1ppm and keep it there. The daily nitrate production is 1ppm in a 1000l system, so 1000mg or 1 gram of nitrate has to be removed daily before the level will descend.
At 40 ppm a flow of 25 litre/day is needed to make it possible to remove 1000mg nitrate daily. When the level of 1ppm is reached 1000l/day must pass the reactor to make it possible to remove 1000mg nitrate daily. This is 40x more. How this would be handled by a BIOpellet reactor? Can this be managed?
Using a Sdenitrator I can do this with the same unit just by correcting ( increasing) the flow. Once the desired level is reached one can decide at what nitrate level the system must be kept and maintained. Nothing to dose, nothing to replace. No money to spend. ( except for lime if a Ca-unit is used.)

[Reefnub]

Yes the bio pellet reactor has a pump the pulls water in and at the same time runs the same water through the reactor again and again and there is a valve at the exit point so you can control the amount of water being cleaned of nitrate in a day which lets you control the amount of nitrate being reduced on the reef system.

[degrijze]

Yes the bio pellet reactor has a pump the pulls water in and at the same time runs the same water through the reactor again and again and there is a valve at the exit point so you can control the amount of water being cleaned of nitrate in a day which lets you control the amount of nitrate being reduced on the reef system.

The reactor is a normal fluidized bed. The effluent of the Creactor can be controlled to keep the reactor aneorobic. There is a big difference between being able to control the reactor by flow corrections or to be able to control the nitrate level in the the aqua system by flow corrections of the reactor. For the first only small corrections are needed, for the second very large flow corrections are needed. To lower the level from 2 ppm to 1 ppm flow must double.

[Reefnub]

I don't think your understanding me, I can control the water exiting the reactor down to a trickle and not effect the tumble of the pellets inside the reactor meaning I control how much nitrate is being eaten by the pellets and if I wanted to have 5ppm nitrate out of 10 I could do this. So yes I can control nitrate as you can.

[degrijze]

I don't think your understanding me, I can control the water exiting the reactor down to a trickle and not effect the tumble of the pellets inside the reactor meaning I control how much nitrate is being eaten by the pellets and if I wanted to have 5ppm nitrate out of 10 I could do this. So yes I can control nitrate as you can.

For example: A 1000l system contains 30ppm nitrate. The daily nitrate production is 1ppm. The nitrate level in the system has to be reduced from 30ppm to the desired level of 1 ppm and stay at 1ppm. How this would be managed using a bio-pellet reactor?
How would this be done

[Reefnub]

Who does 1ppm nitrate?

[degrijze]

Who does 1ppm nitrate?

I do. We maintain nitrate between 1ppm and 2 ppm because it aids calcification for the corrals. That is what I mean with controlling the nitrate level in the system. We do have better growth at this level as at nitrate levels < 1ppm. And it keeps the occupants of our Sreactor happy.

[Reefnub]

It could be possible with bio pellets but would take time to dial in the reactor I haven't tried to get to 1ppm due to its a new tank and not fully stocked. Would like to be at 4 or 5.

[degrijze]

Is it correct to say:
when using biodegradable polymers or bio -pellets, NP reducing pearls ( not bio-balls), the reactor does not have to be anaerobic. The anaerobic space is produced within the pellet. Oxygen removal on the outside and anaerobic activity in the inside of the pellet. Flow does not have to be controlled to maintain anaerobic conditions. The only flow limitations are max flow to prevent removing the bio-film around the pellet and minimum flow to prevent die of of the bio-film.
The working is the same as VODKA dosing, Nitrate and phosphorus is accumulated into the bio-load, not removed. The nitrate and phosphorus will be removed only when this bioload is harvested, removed from the system before it dies. All the cons and pro's from vodka dosing counts for bio-pellets except for the necessity for accurate daily dosing?
The reactor is very sensitive for power failure?
Please comment.

[Reefnub]

Pellets can last up to 8hrs without problems without flow

[Reefnub]

You must use the correct amount of bio pellets for anyone not to have problems. There is a fine line to find the balance you need but to help with this you need a controllable reactor. The pellets build bacteria on the outside of the pellet which consume nitrate and phosphate and pellet combined and the tumbling makes the pellets rub together rubbing off the film on the pellets Which is pulled out by skimmer and feed corals. If you have too many pellets and too much flow it will strip the tank too much and also create more problems for you.

[Big_Pun]

well with pellets keeping them moving is key, too much and you just blow off bio film and they will not work properly, too little and they clump and become a nasty clump of ammonia rotting mass. what the key is finding the correct amount of pellets and flow for your system, trial and error is best way, start off with half recommended dosage amount set by manufacture and test and log them for about 4 weeks and see how levels react. if numbers do not fall then add a little more pellets all while maintaining proper flow. the added benefit i liked is since this is carbon based "sugar" or carbon is released and becomes a food source, my sps and lps seemed to have full polyps extension all day.

[Reefnub]

Guess we're on the same page Big Pun lol

[Big_Pun]

I thought it was easy to adjust my trates with bio pellets, I just ran less volume of pellets

[degrijze]

I thought it was easy to adjust my trates with bio pellets, I just ran less volume of pellets

I have been reading about biodegradable polymers.. Manufacturers advice to start with only half of the pellets as necessary to prevent bacterial bloom. When pellets are added it takes 3 to 4 weeks for the reactor to respond to a higher daily nitrate load. Adding or removing pellets is not what I can call easy management. When 1ppm daily has to be removed level has increased at least 15 ppm before the reactor will be able to start reducing the level in the system. Manufacturers also advice to use a quantity of pellets in correspondence of the volume of the system. The quantity of nitrate to remove daily has nothing to do with the volume or the nitrate level in the system. To lower the nitrate level one has to remove more than the daily production, so the quantity should be based on the quantity of nitrate to remove daily. As flow does not matter, this would be manageable if reaction time was not so long. A sulfur denitrator takes 2 to 3 days to react. As far as I can tell it takes 2 to 3 weeks with bio-pellets.

[Big_Pun]

well first off your giving me off the label info, nothing i do not know. i used pellets for about 3-4 years on diff tanks with good results. yup it takes time but that increased gradual change is less stressfull to a tank, ive doubled the dose of pellets in my system in the past and once they kicked in it took algae out and also the color of my sps(tank at zero nitrates), so i like the slow gradual change in trates. when nitrates creep up no damage is done to coral. popping off a top of a reactor and putting in some pellets is easy and not a big task, i also mark on the outside of my reactors with a line to tell me what optimum volume is of pellets, so i can shut off reactor and see how much have dissolved and top off as needed, basically its a base line. with all thing in this hobby there is more than one way to do things and they may not work for others, this is what i found to work because i have actually used them and not copied stuff off the net. i also run a nice refugium of macro algae to help with nutrient transport, and also a skimmer rated for at least double the tank volume to pull dead matter out with ease and quickness.

[Reefnub]

Well said Big Pun

[degrijze]

In a mixed reef with high feeding we try to keep the level at 1ppm. The daily nitrate production is high, +-1ppm. When feeding is changed due to introduction of other or more annimals we want the nitrate level stays at +-1ppm. Using a Sulfur dentrator a flow correction will solve this and the nitrate level will increase a bit to be back at 1ppm after 4 or 5 days. Nitrate level can be kept at a stable level.
When the same happens using biopellets nitrate level may increase during a few weeks and than decrease quickly to a nitrate level over which I have no control. When biopellets has to be added to remove the dail production it may take weeks before it starts to do so. I will not be able to keep the nitrate level the animals are used to live in.
It has been proven that nitrate and phosphorus loaded bacteria may be beneficial as food for corals.
If my aproach concerning biopellets is correct I do not see how a biopellets reactor can replace our sulfur based reactor. It would be difficult to maintain a steady low nitrate level with high and/or changing daily nitrate production. With a biopellets reactor it seems to be more difficult to manage the nitrate level in the system due to the slow reaction on changes .
An other advantage is that we do not have additional expenses, biopellets have to be added each 4 to 6 months or more often when a high daily nitrate production has to be removed daily.
For the moment I can not see how biopellets could be a good alternitive for BADES. We think about adding a small one though, just as a food source for the corrals or would it be cheaper just adding a few drops ethanol?

[Big_Pun]

well you keep saying "may" so you don't know then, just speculation from what you read and not actual experience. what matters is the end result and my tanks did well with pellets, you just need to put the time in and know your reef. both methods work just pick one and educate your self on why they work and talk to people who have actually used them

2544125442

[degrijze]

This topic is about biopellets vs Sulphur denitrator. I have no experience with biopellets of the last generation; In the beginning I even mixed up a carbon reactor with biopellets , which actually does reduce nitrate to N but have to be kept aneorobic and flow regulation is very limited. Biopellets do not remove anything, they cultivate bactaria who may accumulate the nitrate into their tissue but also not desirable bacteria, when present, are fed. An other apparatus has to be used to remove the nitrate loaded bioload, mostly a skimmer. When the skimmer does not remove the bioload the biopellets are waisted because nothing is removed. One has to count on two things to have results. An expensive but easy way to dose vodka.
The nitrate level in the system is not controllable using biopellets because the working is to slow to follow nitrate production fluctuations and the quantity of nitrate removal is not predictable. Al these remarks does not count for a BADES system.
I do have a lot of knowledge and background about the use of Sulphur denitrators and how to manage them. When the reactor used is big enough one has just to adapt the flow to the nitrate level in the water to remove the daily production of nitrate daily. Nitrate level in the system can be controlled and kept steady at the desired level even at very high daily production. Once the reactor is balanced at the desired level nothing has to be done, the reactor is self-regulating.
Keeping sps corals and high feeding is no problem. Mixed reefs are not limited by food..
Maybe I keep saying " may" because my native language is "Dutch" and my English "may" need some polishing.
I may conclude that everything is in favor of the sulfhur. More reliable and predictable nitrate reduction. And a lot cheaper.

[Big_Pun]

I keep saying I was able to control the levels but you keep saying you can't. but have no experience with them so how can you correct me. amount of pellets and flow basically thats its. also running a refugium helps, more nutrient export, also a good skimmer to remover waste from bio pellets. all these factors help control and keep a steady base line. yes i know with sulphur you can up the output, but honestly unless the swing is huge a home eco system isn't as sensitive to swings .

[degrijze]

I keep saying I was able to control the levels but you keep saying you can't. but have no experience with them so how can you correct me. amount of pellets and flow basically thats its. also running a refugium helps, more nutrient export, also a good skimmer to remover waste from bio pellets. all these factors help control and keep a steady base line. yes i know with sulphur you can up the output, but honestly unless the swing is huge a home eco system isn't as sensitive to swings .

When it comes to making a choise between two systems one has to compare the con' and the pro's. And yes, I keep saying that with biopellets one has no control over the nitrate level in the system. I did not say you where not able to. Biopellets may remove nitrate in combination with other devices but the working depends of the good functioning of that other device. When more food is added and/ or live stock iis increased it will take 2 to 3 weeks before one will know the biopellet system is able to remove the nitrate increase and yes, all that time the nitrate level in the system will increase and can not be kept steady. One has no control at all! Biodegradable pellets have to be added regulary. It is commercially more interesting as a Sdenitrator.
When using a sulpur denitrator as part of the system it will close the nitrate cycle and makes it possible to have full control over the nitrate level in the system. It will take 2 to 3 days to respond to big changes. Small nitrate production changes will not be noticed. It will keep the nitrate level on the level of choice. The Sdenitrator does not depend on other devices to reduce nitrate and remove it.

[degrijze]

I know a lot of people had problems with sulphur denitrators but in 99% of the cases these problems occurred because the reactor was not big enough for the system and was mismanaged because of the fact the user did not know it was to small. A sulfur reactor must not be managed the same way a carbon reactor is managed. Most people will start to use a Sdenitrator as a problem solver to reduce high levels. This can not be done when managed the same way a Creactor is managed following the guidelines of some manufacturers of reactors. When used as a problem solver and the parameters of the system are not known a 1% reactor will do the job without being encountered by the limits of the reactor avoiding possible mis-management. When level decreases, increase the flow true the reactor to be able to remove more than the daily production. When the level of nitrate in the water descends more water has to pass the reactor to make it possible to remove the same quantity of nitrate. Enough space must be available for removing the increased supply of oxygen. That is why it must be big enough!

[Big_Pun]

actually it doesn't take that long to see levels drop once you add more pellets its like 3 days, your forgetting the bio culture is all ready established so adding more doesn't restart the whole process.

[degrijze]

actually it doesn't take that long to see levels drop once you add more pellets its like 3 days, your forgetting the bio culture is all ready established so adding more doesn't restart the whole process.

That may be wright for the pellets in use but does not count for the pellets added. Lab tests proved that it takes 8 days to develop denitrificating activity on the new pellets followed by a lag time (=period of adaptation of denitrifying microorganisms) of 16 days. ( Biodegradable polymers as solid substrate and biofilm carrier for denitrification in recirculated aquaculture systems A. Boley *, W.-RMuller, G. Haider Universitat Stuttgart, Institut fur Siedlungswasserbau, Wassergute- und Abfallwirtschaft,)

Using a Sdenitrator there is nothing to add, a flow correction is enough.



The graph shows when a supplement food (nitrate) was added on week 10, it took 3 weeks to remove it. This graph is from the test from a manufacturer of biodegradable pellets. No pellets added. No information about how much was added.

25445

Anyway. When one is satisfied with the result of the method in use, every body happy.
Which is the best method, bioballs or sulphur? it's an open discussion.
I know the sulphur will win and it is certainly the cheapest. But " maybe?"

Some one interested in BADES may always contact me.

[ikishk]

Maybe bringing in a 3rd option to this thread will liven it up a bit! I made an anaerobic coil denitrator back in 2007... **** does it work! the concept is simple, but to simplify it even further, we can call it a second refugium for anaerobic bacteria *lol* So, my initial research landed me here: http://archive.reefcentral.com/forums/showthread.php?p=11579579 it was the best example I found at the time... back then it was still, for lack of a better word, experimental. designs really didnt take into account max efficiency and maint. people had still been trying to make "stagnant" anaerobic water, not so much an anaerobic loop which could feed itself. This one link I based mine on, started down that path. I just kinda supersized it w/ logic.

He used normal sized bioballs. I used the mini tiny red bioballs... I think that increased surface area by like 60% (i did the math back then and dont recall the exact number, dont hold me to that). I also wrapped my 1/4 line on the outside (other designed had it in the inside, wasting space). I found 3" PVC worked best, and sized mine to fit under the cabinet at the time. I'm pretty sure 4-5" pvc would exponentially based on internal surface area provided. I also tried added a second layer of 1/4 wrap around the 1st layer, but this did not really improve much.

The whole idea is to feed water in slowly from the top of the coil, by the time it gets to the bottom, it is mostly anaerobic. The oxygen in this slow system tends to rise agaisnt the flow, by adding a second coil gong upwards, it simply was mixing with the oxygen as it traveled. looking back, i shoudl have just made the second could travel down as well, with a single upwards direct connection to the 1st coil. The base of mine is also a typical septic cleanout cap, If i ever needed to... clean it out (havnt had to). I seeded it with "biozyme" (which i think is just dried shrimp w/ dried bacteria on it).

About 3-4 weeks after I installed it on my then 75g tank, it took off. I walked into the house and smelled sulfur. FINALLY! at this point i lowered the effluent into the water, where it mixed and the smell disappeared. I occasionally pulled it out of the water to check drip rate. early on, it would get stopped up frequently, as the colony bloomed. once it stabilize, I really didn't have to touch to check it for weeks at a time.

I broke that tank down in 2011. I moved the liverock into a new trashcan w/ a heater/chiller/pump. I moved the coil onto that as well. I recently got a new tank in 2014. Assumed my liverock and coil would still be good, sitting in the dark, stuff decaying, coil and liverock having nice "boon." That trashcan ran for 3 **** years just fine... problem was, the coil worked so well, there was no nitrates to be found, and no sources of nitrates! my nitro-cycle crashed, coil and everything. Of course I didnt notice this until tested the water AFTER i moved the liverock and coil to the new system.

the coil took about 6-8 weeks this time... i went from 75g system to 250gal system. Apparently the old liverock and coil still had something in it, my new tank cycled in about 7 days w/ the cyano bloom lasting maybe 36hrs. Theres about 150 more lbs of liverock in the new system as well, so that seemed to get cross-seeded faster.

So now my super-efficient(for 75g) coil cant keep up! added a wholehouse (3.5liter i think?) canister loop w/ nitrate sponge (4 weeks ago) and fluidized sand bed in a 5gal bucket (8 weeks ago). Started the vodka dosing rampup I found here http://reefkeeping.com/issues/2008-08/nftt/ 3 weeks ago. So, if the planets align, I should have my nitrates back under control 2-3 weeks from now, and my coil will be back into shape, which in turn will cause me to reduce the vodka-dose at the time.

That was longer than I anticipated, sorry *lol* (i have a diagram of the plumbing mess under by albums)

[Dkray944]

Very interesting topic.... I'll have to read up on it