High Nitrates - Replacing Sandbed...?

[stephencraig]

I'm still having the high Nitrate issue with the corner tank. Since nothing else has seemed to work, except trying Vodka dosing which is kind of scary and only really treats the symptom, not the problem, even if it did work, unless someone has any other ideas (Please! I would love to hear of any alternatives from the one I'm about to propose)....I guess my only choice here is to assume the problem is the sand bed.

Please bear in mind, this tank will eventually be combined with my other tank into a 180 - 210g tank sometime next year, but since I don't know yet if that would be as early as January or as late as mid summer, I guess I need to start doing something now about the sandbed.

I was told by the owner of a LFS here that I could do the sandbed by suctioning off about an inch at a time in sections. He said I could suction off about an inch (he actually suggested doing about half at a time, but I doubt I would do that much) when I do a water change, wait about a week, then vacuum that section, wait a week or so, then repeat the process in the other section.

I would like your opinions on this as this whole sandbed thing really scares me. If I followed this procedure, I would probably do more like a third or a fourth of a section at a time.

Stephen

[hobogato]

i have never heard of a sandbed causing high nitrates unless you dont have anything like snales, etc. to move it around and keep the detritus from building up. how deep is it? to get the denitrifying benefit (nitrate elimination) of the sand bed it needs to be pretty deep - 5" or more depending on the size of the sand particals.

[Richard]

How deep is the sandbed?

[hobogato]

how deep is it?



How deep is the sandbed?


is there an echo in here? :P :lol :lol

sorry richard, couldnt resist and i know you apreciate a little humor :)

[SaltyJim]

Hate to start a new debate, but I have been reading the 40+ pages on RC about a RDSB. That in conjunction with your shallow SB in the display (3-4" is not deep enough) might help. Here is the link to the first of many pages on the subject...all started by Calfo.

http://reefcentral.com/forums/showthread.php?postid=7842431#post7842431

Seems like some are getting good results rather quickly. Good luck.

[Richard]

Huh? I don't know what you talking about Ace LOL. Oh, I forgot to mention to get the denitrifying benefit (nitrate elimination) of the sand bed it needs to be pretty deep - 5" or more depending on the size of the sand particals.

[stephencraig]

Ace and Richard, the sand bed runs 2 to 3 inches deep.

I've had several threads on ARC about this, but to catch both of your up...

Its 92G corner tank, contains 8 fish (from a small neon Goby (the smallest) to a Sailfin Tang (largest) that is maybe 4 inches). Nitrates have been running about 40 ppm. I tried aggressive 30 - 50% water changes for a while, and although that would normally knock the Nitrates down to the 10 - 20 range, it would crawl back up to 40. The tank has about 200 pounds of LR, about 80 - 100 pounds live sand. Has a Ocenaic sump, and small Tunze Skimmer. I have cleaned the sump out several times, removed the bio-ball chamber and now have Chaeto in that chamber with a small nano dual compact that I leave on 24/7. I have tried the Fritz bacteria. For critters I have various species of snails, hermit crabs, too many bristle worms, a small (which I haven't seen in a while) sand shifting star, and a larger sand shifting star, and 3 fighting conch's.

I know I'm not over feeding, because I also have another 90g tank with a few more fish, only about 130 pounds LR and 80 pounds LS, that I feed exactly the same as the 92G, that I run 0 Nitrates on. The high Nitrate tank was an established system with the sandbed probably being about 3 years old. The No-Nitrate tank is the first one I had when I got into the hobby, and is about 9 - 10 months old.

Let me know if there is any other information on the tank that you need.

Stephen

[hobogato]

:lol :w00t

Jim - that is how i have my system set up. 3" or so of special reef grade (larger partical) in my display and abut 7" of sugarfine topped with about 1" of special reef grade in my fuge. it has worked very well in my setup so far, but it has only been set up slightly longer than a year.

[stephencraig]

SaltyJim,
My proxy server here at works for some reason blocks the RC forum (thankfully not this one, though), so I can't read the thread you posted until I get home.

What is a RDSB?

Stephen

[hobogato]

Remote Deep Sand Bed - you saw one at my house when you looked at my filtration.

[SaltyJim]

:lol :w00t

Jim - that is how i have my system set up. 3" or so of special reef grade (larger partical) in my display and abut 7" of sugarfine topped with about 1" of special reef grade in my fuge. it has worked very well in my setup so far, but it has only been set up slightly longer than a year.

I'm sure your's looks much nicer than the (insert favorite salt brand here) bucket. See, I could have known that if you had taken pics of your plumbing for me ;)

[hobogato]

sorry jim, the laughing faces were meant for richard - i was just agreeing with you ;)

[stephencraig]

OK, so figuring that I'm going to consolidate these two tanks into a 180 - 210g in the next few months, and I'm not sure if that will be sooner (January) or later (this summer), would you suggest that I consider the RDSB now?

What has me so stumped is that there has to be something "holding" the Nitrates. Since I've tried to eliminate everything else because I really do not want to mess with that older sand bed after I moved everything to the new larger tank, I can't think of what else it could be.

What are your suggestions, considering...? Move to RDSB now (not sure if I even can because of space in the cabinet), or slowly remove the existing sandbed a little at a time? That is about all the options I can think of except trying Vodka dosing (which is a little scary too), or buying/making a coil denitrator.

Stephen

[stephencraig]

"Remote Deep Sand Bed - you saw one at my house when you looked at my filtration."

That's why I need to bring my camera next time I come to get frags.

Stephen

[hobogato]

there is not necessarily something "holding" the nitrates.

ammonia (fish waste) gets changed into nitrite by bacteria. that nitrite gets changed into nitrate. the bacteria that process the nitrate and change it into nitrogen (which dissolves out of your tank into the air) have to have anaerobic conditions to do their job. hence the deep sand bed.

the other way to keep them from building up is macroalgae which consumes nitrates as it grows, so when you harvest it from your tank, you are essentially eliminating nitrates

or

a really powerfull skimmer to pull out all of the detritus before it can settle to the bottom of your tank (and decay causing a buildup of nitrates in the end), but this works best on a bare bottom tank.

[SaltyJim]

Since you are already planning on removing the existing bed in the display tank, just do that when you upgrade. IMO trying to remove the SB now would cause a lot more trouble, or not solve anything if you go at the slow recommended pace. If you can get the real estate, you could do the RSDB in a 5 gallon bucket , and you can plum it off any return in the tank. Just has to be slow flow. If it doesn't work out for you, just disconnect it from the system. The most you would be out is the cost of the sand and pluming parts. I'm sure you have an empty salt bucket, right? From some of the success stories on RC, you might start seeing the results in a couple of weeks (assuming you keep up with the other tank maint.).



"Remote Deep Sand Bed - you saw one at my house when you looked at my filtration."

That's why I need to bring my camera next time I come to get frags.

Stephen

hey, while you are there, snap some pics of the rest of the plumbing for me :lol

[stephencraig]

OK, so I'm trying the macroalgae route, but I probably don't have enough in there to see any affect yet. I guess all a coil de-nitrator is doing is giving a place for that anaerobic bacteria to do its thing as well. If I could do the RDSB, what size should it be for this 92g tank?

Another thought just ocurred to me. So if i can't do a RDSB because of the space limits in that cabinet, would adding more live sand to the display tank work? If it would, how long would it tank to see an affect (several months?) and what kind of sand (as in sugar fine, reef grade (would that be like CaribSea?), or what)?

Stephen

[hobogato]

jim, as soon as i get home ill snap some for you.

[matt]

I woul also try the remote sand bed. First thing would be to head over to reefcentral if you can and read that monster thread. I think the results can be pretty dramatic. As far as the macroalgae route, you're going to need ALOT to quickly reduce the nitrates.

As some others have said, it's not that you're "holding" nitrates, it's that you're producing nitrates faster than the tank can process them. Macroalgae will consume some nitrates, but I think it's better at keeping low levels than quickly reducing high levels. For that you really need the anaerobic bacteria in the DSB.

One quick test you can do on your sand bed is to pull out a "plug" of sand, maybe using a PVC tube, and see if there's a strong rotten egg smell. If so, that's an indication that your sand bed may be polluted with detritus build up and this could be adding significantly to your bio load. In a healthy sand bed (according to Ron Shimek) there is no hydrogen sulfide (the rotten egg smell) because the animals (bacteria, mostly) are consuming waste products all the way down the food chain to nitrate, then free nitrogen.

[SaltyJim]

So if i can't do a RDSB because of the space limits in that cabinet, would adding more live sand to the display tank work?
Stephen

I don't think you would get the same effect. The whole point in the design that is talked about in the thread is that you are sending a flow that is just fast enough to keep particulate from settling on the top of the sandbed. And a fairly shallow column of water on top too. But, not to say you wouldn't see a benefit, just not quickly.



Ace, I'm just giving you a hard time. But if you take 'em, I'd still like to see. :D

[hobogato]

taking the camera downstairs now - be right back.

[hobogato]

sorry for the hijack stephen -

jim, this is my filtration. tank drains into first pic (left side of the sump/fuge) and the return pumps are in the chamber behind pic 6 (far right side of the sump/fuge) the whole thing is one 6'6" tank divided into sections.

80 lbs of LR rubble in the first chamber
http://i30.photobucket.com/albums/c329/hobogato/projects/filtration1.jpg
beckett skimmer in the second chamber
http://i30.photobucket.com/albums/c329/hobogato/projects/filtration2.jpg
8" or 9" DSB fuge in the next chamber with mangroves and a little chaeto
http://i30.photobucket.com/albums/c329/hobogato/projects/filtration3.jpg
http://i30.photobucket.com/albums/c329/hobogato/projects/filtration4.jpg
last chamber with return pumps (mag12 and mag18) and skimmer pump (mag12) behind calcium reactor and kalk reactor
http://i30.photobucket.com/albums/c329/hobogato/projects/filtration5.jpg
http://i30.photobucket.com/albums/c329/hobogato/projects/filtration6.jpg

as you can see by my pH controller, i am still dialing in my calc reactor since i changed the media a couple of days ago - the pH of the calc reactor effluent stays around 7.0 when dialed in correctly.

[stephencraig]

Hey SaltyJim, we're just down the road from each other. I'm off Oak Knoll and 183.

Good to know about the 5 gal bucket. That I can swing. So I would want the bucket to have 5 - 6 inches? If I had the choice, would I want the flow to go from the tank into the DRSB first - before the sump and skimmer, or after the sump/skimmer before it goes back into the tank? Or would I just set up some piping and small pump from and to the sump itself?

Stephen

[stephencraig]

That's okay, I needed a refresher on the pics too. Thanks!

Stephen

[stephencraig]

Oh, and any particular live sand, or will any "live sand" do? Will I need to worry about it cycling, or can I set this up and get the flow going thru it right away?

Stephen

[SaltyJim]

ok. Let me see if I can rephrase what I have read of the 70+ pages :lol

Take a 5 gallon bucket.
Install plumbing toward the top of the bucket. Possibly Uniseals and PVC or bulkheads for this. Make the in and out on opposite sides of the bucket.
Fill bucket with dry (not live, wrong type of bacteria) to 3-4 inches below plumbing. If possible, some aragonite sand.
Fut a slow, steady flow through the bucket. I think most were about 200gph or less, so small pump or ph. I would pull the water from your skimmer return possibly, to help reduce the possibility of detritus getting to the bucket.
Cover bucket to reduce algae (optional)

With this, no sand critters are needed since you are trying to promote the anaerobic bacteria to flourish.

And Ace, thanks for taking those pics. I'll have some ?'s later.

Take a look at these pics.

[hobogato]

pretty cool - same concept as mine. since i work with acrylic, it was easier/more convenient for me to do it the way i did. the bucket method is awesome for saving money and getting a great nitrate remover :)

[SaltyJim]

Sorry, forgot to credit those pics. bguile from RC on page 40 here http://reefcentral.com/forums/showthread.php?postid=7842431#post7842431. Not my creation.

I need to mention that the buckets can be permanent, but in Stephen's case, I would call it more of an emergency plan to help with nitrate removal. I think you will need to keep this on the system until you get the new tank established, then remove it when moving the livestock. Some discussion about removing the RSDB and how much of an impact removing that much bacteria from the denitrification cycle would have on the overall system health. So, for the new tank, if you want to have the DSB, put it like Ace did inline in a fuge. Just my opinion.

[stephencraig]

Sounds good. Thank you both for the help. I'll try to get through the thread in the next couple of days. In the meantime, this gives me something I can start working with now.

Thanks again!

Stephen

[safeuerwehr]

and small Tunze Skimmer.


How Small? I had a similar problem when i was using a small skimmer on a 125g....I upgraded my skimmer and it resolved alot problems I was having with my tank...

[stephencraig]

I'm not sure of the actual model. Its one that sits cross ways in the 30g sump. I have a big Euro-reef that I have on the other tank that will be big enough for the larger tank when I combine them. One of the reasons I have not upgraded the Tunze. Also space would be an issue. If I run across a good deal on a used one, though, I might consider changing out the skimmer too. I'm trying not to buy anything that I can't use when I move these two tanks into the larger one.

Stephen

[Jeff]

check the flow going into and around the rocks.to much rock can trap detritus and cause you to have a constant supply of nitrates. i was fighting cyno for awhile and after i removed some of my rock and reaquascaped the cyno went away. if you can post a picture of your rock work.

[LoneStar]

Now this might not be a solution for NOW but when you upgrade to your larger tank, you can aquascape your rocks onto PVC racks and then position powerheads behind them to constantly clear the detritus they build up. Then if you have good flow and a good skimmer, you should be able to take most of it down to the sump where your skimmer should clean it up.

Here is a version of what I was saying. It does not have the PVC racks but it did use a 'plastic dam' and egg crate to allow access for a pump to blow away the detritus and keep the sand from coming under the rock. The photos were taken off a build on ReefCentral. A Deltec tank :)
http://i59.photobucket.com/albums/g309/Mobulid/Img_7496.jpg
And here is how the rock looks stacked over the crates:
http://i59.photobucket.com/albums/g309/Mobulid/Img_7566.jpg

And here is the thread where I found the photos:
http://reefcentral.com/forums/showthread.php?s=&threadid=880909

Its easy and fairly cheap. If you do not have a closed loop, powerhead could work too. I would build a small PVC 'table' and position the rocks on top of it.

This is just a small way of PREVENTING nitrates. Like stated before, its just a matter of how big your bio load is in your tank vs how fast your tank can clean them out. So if you run a RDSB, effecient skimmer, fuge, lots of flow to keep detritus suspened in the water column (so the skimmer/filters can trap it) you might come ahead on the battle ;)

Since you are sticking with sand, I would also agree that the RDSB will be your cheapest route. Just get some cups of sand from a few memebers here to seed it.

[erikharrison]

holy crap! I need to build up my sand too! Mine is about 2-3 inches as well, so I guess I gotta go spend about 30 dollars for another bag of sand? CRIKEY!

[stephencraig]

Here's a pic of it today (still learning how to use me new camera). Not sure how much this helps.

Stephen
http://i96.photobucket.com/albums/l186/stephencraig/IMG_0047.jpg

[stephencraig]

Thanks LoneStar. This is very interesting stuff. I had wanted to build the new one with "something" in it that you could blow stuff out from behind the rocks. This might the answer.

Stephen

[stephencraig]

Lonestar, Does the grate support the rock, or does something else support the grate (where it would have flow under it), which supports the LR?

Stephen

[LoneStar]

Lonestar, Does the grate support the rock, or does something else support the grate (where it would have flow under it), which supports the LR?

Stephen

I'm not sure really. I have not run across that many Deltec tanks. Probably because they are sooo expensive. Either Deltec used regular egg crate or they have some expensive stuff they came up with that allowed flow underneath.

If you stick with sand, I would have some sort of acrylic 'dam' that will skirt around the diameter of your rock structure. Then you can build a small pvc stand to support the rock. Depending on if you use a powerhead or spray bar you can go in either direction. If you use a powerhead, just make sure you can retrieve it somewhat easily for cleaning ;)

I know some people actually turn their pvc rock stands into spray bars (adding loc line fittings to spray under and in the middle of the rock) Of course it will be connected to a closed loop.

Hope that helps!


Or just go bare bottom and get a kick ***** skimmer! :P

[Thunderkat]

I had a 7" deep sand bed in my old tank with a plenum in it and about 10 nassarius snails in a 75 gallon tank and didn't have a problem with nitrates. I also had a 55 gallon tank as a fuge with live rock and macroalgae growing in it (that was excessive, fuge does not need to be that large) with 24/7 lighting and didn't have a problem with nitrates. I have read that oxygen levels can drop very low overnight in tanks with plenums so I added the fuge with macroalgae and lights. If you get everything set up properly a good sand bed can take care of many problems but creates new ones such as excessive coralline growth (yes it is a problem when you are scraping it off your glass all the time).