O.K., Gary, a question about Carbon and reactions in a tank.

[TexasTodd]

Time for a Gary answer. You know, maybe we should have an "ask G" forum. :D

Here's what happened.

Full SPS tank with all parameters in line except ORP a little low, but PH is a little high right now.

I have been running the Ozone for quite a while. I have not run ANY carbon on my system for about a month. Tank and animals seem to be fine.

I've noticed my ORP steadily going lower (with consistent probe cleaning). I'm going to do a water change, but was curious about trying some carbon first even though it is "not supposed to be used" on a bare bottom tank. But of course is supposed to be good with Ozone.

So, I took one of the filter socks I got from Donny, filled it about 1/5th with carbon, rinsed it in RO and put in on the draining end from my overflow.

The next thing I see is my Skimmer go completely nuts! My guess is from residual carbon dust. YES?

Then my AquaController alarm goes off because my ORP has dropped from like 330 to 190 in a matter of a couple of minutes! PLEASE EXPLAIN.

The ORP slowly climbed back up and an hour out was back to 300.

What went on chemically in the system to do this?

Thanks much,

Todd

[GaryP]

You probably had a momentary spike in COD (chemical oxygen demand) and that caused your ORP to fall. I have never seen my skimmer "go nuts" from carbon. I change out the carbon on a weekly basis on my tank. You got me on that one.

Remember that CO2 is a reducing gas and residual from the reactor can cause your ORP to go lower. The other source of material that could lower your ORP is organic chemicals that again could be cause an increase in COD and BOD (biological oxygen demand). I've never used a hobbyist type ORP probe/meter so I'm not real sure about its operation. Is there any way that it can be calibrated or QC'ed? Is the membrane changeable? The ones I used had a cellophane type membrane that has a special fluid under it. The ones I used were from a company called YSI and they are combination of O2/ORP meters and we calibrated them every time we used them by calibrating against air (21% O2).

If you have ever read any of my other posts I am very skeptical about the quality of hobbyist types of analytical equipment.

[TexasTodd]

Thanks Gary. I think the skimmer going crazy was from extra carbon dust I didn't rinse all out. As the skimmers calmed down after an hour or so and the first skimmate was laden with fine carbon dust....black.

Yes, I've heard you discuss the hobby ORP. My feeling is I use it as a Trend instead of an absolute. They will read exceeding higher and higher if you don't clean the probes at least 1x per week in vinegar.

So, the carbon sucked a bunch of oxygen out of the system's water quickly?

Thanks Gary,

Todd

[GaryP]

So, the carbon sucked a bunch of oxygen out of the system's water quickly?

I can't say that was definitely was what happened, but its the only theory for what you observed that I could come up with. I'm sure it was only a temporary issue and quickly returned to normal as a result of normal gas exchange and your ozone. I willing to bet, if you watched closely, that you would see a similar trend occur after a feeding, when a relatively large amount of organics are introduced into the system.

[Richard]

but was curious about trying some carbon first even though it is "not supposed to be used" on a bare bottom tank.


Why is that?

[::pete::]

but was curious about trying some carbon first even though it is "not supposed to be used" on a bare bottom tank.


Why is that?

Because its one of those things typed somewhere!! :P

[GaryP]

Why is that?

I've been asking the exact same question as well as why you aren't supposed to use a fuge with a BB tank. Sounds like a lot of arbitrary rules.

[TexasTodd]

And...............that's why I tried it! :)

The theroy is that if you have a BB set up properly. 1. Carbon and phosphate binders are not needed.
2. that these compounds STILL put some chemicals in to the water by putting them in you system.
3.There is not supposed to be enough organics in your system to run a fuge. Fuges need detritus to grow/feed the bugs and algae.

Like I said, all theory. The king of BB also turns his nose up at Ozone and opts for UV instead. Which is great except it costs more, you must replace bulbs, and most importantly, adds a ton of heat.

Yes Gary, the ORP bounced back within an hour. But, it did drop OVER 35% within minutes of the carbon going in.

Here's another question. What if my system had built up the Bromine/Bromide.....whatever it is that Ozone is supposed to cause in salt water. Would that make the carbon react quickly? Or, is it still such a small part of the total water that there would be no noticable effect?

T

[NaCl_H2O]

Gary, this is the PinPoint ORP probe that comes with the RedSea Ozone unit. Given the metal post, I assume it is some type of conductive probe?

Todd, what about the simple answer ... your ORP didn't change at all, but the carbon dust in the water (carbon = conductivity) messed up the reading of the ORP probe? If your ORP "Really" dropped 35%, I don;t see how it recover in only one hour, but the carbon could have been cleaned out of the water (by the skimmer :D) in that amount of time.

My skimmer went nuts on me once due to carbon dust, now I rinse it really good!

[Richard]

The theroy is that if you have a BB set up properly. 1. Carbon and phosphate binders are not needed.
2. that these compounds STILL put some chemicals in to the water by putting them in you system.
3.There is not supposed to be enough organics in your system to run a fuge. Fuges need detritus to grow/feed the bugs and algae.


I love all these theories. So a BB tank will keep your tank so clean that you don't use carbon and also so clean you can't even have a fuge. Yet you found the need to use carbon and ozone. Hmmm?

[gjuarez]

Another reason why a fuge is not recommended in a bare bottom tank is because a bare bottom tank normally should have a lot of flow to keep detritus in suspension and finally having it settle on the sump. According to some experts, a barebottom aquarium should be detritus free. A place like a fuge would serve as a refuge for detritus. According to Bomber's theory, detritus should be very minimal in a barebottom tank and all organics should be taken out immediately by using an oversized skimmer. IT has worked well for me. BTW Todd, I saw you posted on RC about the T5 lighting on the german tanks, did the person answer your questions. IF so, can you pass the info to me. FOr some reason I cant get into RC.

[GaryP]

OK, what about the DOC and phosphate that comes from fish waste? Where does that get taken out in a BB tank? In theory I suppose its removed by skimming. Macro algae in a fuge doesn't require detritus buildup. I suppose you could even do a BB fuge with Chaeto.

My whole problem with this theory is that waht works for one system may not work for what is apparently an identical system because no two reefers manage their systems in the same way. Livestock is different, feeding is different, and additives are different. Todd, my advice is to just do what works for you. There are way to many gurus out there that are quick to reach conclusions without a clue as to how a system is set up. I suppose I have been as guilty of that as anyone else in my haste to help folks so I can't be to critical of them.

Steve - I suppose your theory may work if there was a fine coating of carbon dust on the electrode. I never really thought of carbon as being particularly electrically charged though. There are, however, metallo organic compounds (called lignins) in all organic matter. Chlorophyll in plants and hemoglobin in animals are examples of them. These could give the carbon some electrochemical properties.

My thinking on the bromine theory is that it would be removed by the carbon the same way that ozone or chlorine is removed by carbon. That actually makes a lot of sense to me. If bromine is produced by the ozonator, it would be converted to hydrobromous acid which in turn would react with the carbon. The resulting decrease in oxidizing species would result in a drop in ORP. The dust in the water has a very large amount of surface area that is available to be reacted on but the total mass is fairly small and it would be rapidly spent. If carbon reacts with oxidizers then it is a reducing compound by definition. Therefore, its presence would very likely cause a temporary reduction in soluble ORP until the reducible reactive sites on the particles are used up. My understanding is that carbon is normally recommended to be used on the air venting of a skimmer to prevent ozone being vented into a home.

The one thing I don't understand about how ozone works in an aquarium is this: Ozone is supposed to increase the effectiveness of a skimmer. As a matter of fact I know that some people recommend piping its output dirrectly into a skimmer. HOWEVER, the way ozone works is to break down the organic chains into smaller chain lengths by attacking unsaturated bonds. It would seem to be smaller chain length organics would be more water soluble. Skimming is based on the hydrophobic/hydrophilic characteristic of long chain fatty acids and lipoproteins. Is it just me, or is this counter intuitive? The lower chain length carbon chains will contribute to the DOC. This is exactly what activated carbon is going after, the more water soluble molecules that skimming is less effective at removing. It seems to me that ozone would also produce smaller organics that are more readily digested by bacteria and other critters that feed on DOC like macro, leathers, Xenia, and mushrooms. So, maybe a wet/dry may be a good companion device to the use of ozone.

Todd - Have you bounced this off of Randy Holmes Farley on RC. I would like to see what he would have to say on this. If you can't reach him there, let me know, I think I have an email address for him.

OK, I have probably lost everybody here. I'm just thinking "out loud" here. Please feel free to poke holes at my ramblings.

[TexasTodd]

No, that was good Gary.

Yes, people say to use the carbon on the venting of the ozone, but, it's also supposed to be used on the water effluent to get rid of the bromine I guess.

That does make sense, if I follow your post, to use carbon in the water when using ozone. If the skimmer is taking what it can and the ozone is breaking things down in to water soluble, then the carbon should help binde up the woter soluble stuff.....right?

Richard, yes, the theory is you have massive tank flow to keep all detritus suspended. It is then run through big skimmers that are set to run "wet"--green tea colored skimmate. Further you are supposed to have a spot in your sump(s) for any un-skimmed detritus to settle out. This is frequently vacuumed out and fresh saltwater replaced.

Gary, yes, I have thought about adding some Cheato.........espically after seeing Donny's impressive BALLS! :)

Thanks guys,

Todd

[GaryP]

Todd, what do you mean by using ozone on water effluent?

My understanding of how ozone works is to increase the ORP by introducing more oxidizing species such as ozone, bromine, and peroxide; but to also increase ORP by reducing species such as waste compounds.

[TexasTodd]

Almost everyone using ozone pipes it in to their skimmer. Many then recomend having the effluent from the skimmer go through carbon to remove the bromine/bromide (whichever the ozone makes).

The carbon would also remove any excess O3, but most concure that this in not needed as the O3 levels are low and gone before exiting the sump.

Q, missed your note about RC t5, yes they answered. Check to see if you can get on rc now. If not I'll try to copy as it took a few posts to answer all.

Todd

[GaryP]

I don't go on RC very much, unless someone links something there. I have a hard enough time keeping up with what is going on here.

I thought you were referring to the skimmer effluent. I read about that when I was real new to the hobby in Martin Moe's book which is an excellent resource on water treatment and chemistry. He's supposedly doing an updated 2nd edition which is probably long overdue. The basic principles haven't changed, but the technology in the hobby certainly has.

Any sort of oxidizer treatment is based on the idea of maintaining a very low residual of the oxidizer. The water has a certain demand. The demand is the amount of the oxidizer that will be used up when added. In the case of municipal water treatment, for example, the goal is 0.5 ppm of chlorine. If the demand is 100 ppm, then the amount needed is 100.5 ppm to achieve a .5 ppm residual. I used to work with chlorine dioxide for industrial water treatment. It has 5 times the oxidizing power then regular chlorine gas. Therefore, the amount needed to meet the demand is 1/5 as much and you only need 1/5 as much of a residual to achieve the same level of bacterial control.

[Richard]

My thinking on the bromine theory is that it would be removed by the carbon the same way that ozone or chlorine is removed by carbon. That actually makes a lot of sense to me. If bromine is produced by the ozonator, it would be converted to hydrobromous acid which in turn would react with the carbon. The resulting decrease in oxidizing species would result in a drop in ORP.


That seems to make sense to my non chemist brain but wouldn't that mean he had a residual amount of bromine in his tank? I would think he would be losing animals if that were the case.



carbon to remove the bromine/bromide (whichever the ozone makes).


Todd - I don't care too much about the detailed chemistry of things. It may not be completely true from a chemists viewpoint but I just consider that ozone can convert "ides" to "ines".
bromide --> bromine
chloride --> chlorine

[TexasTodd]

Yes, I believe it does Richard. At least on the bromide to bromine. But very low amounts. But, that's why the O3 gurus say you're freaking crazy to run O3 on a reef without at least intermittant carbon.

All I know is my corals are fine, my water is CRYSTAL clear and my fish aren't getting sick. UV is probably safer, but I don't have the money or the chiller capacity right now to go that route. Maybe down the road though.

All I need now is a CBB. ;) :lol

[JimD]

The K.I.S.S. rule has always worked best for me.... :)

[schoeplein]

Its funny how much sense you made, Gary. Logistically, that's how it is. Skimmers can't remove everything. Carbon can't remove everything. Phosphate pads and everything else can't remove everything.

I just know from personal experience that cleaner (clearer) water and an absence of any odor were really my only findings. It removes forms of free-floating biological matter - the size of biological matter removed depends on the type of carbon as there is a broad spectrum of carbon types and particles depending on how it is manufactured. Many people fail to place pre-filtration devices before their carbon and thus have tons of detritus buildup in their carbon pouch. Many people also fail to place their pouch in a position in which water will be moved through the carbon (not just over or around the pouch) - an overflow from the skimmer is a great place.

[GaryP]

I only use powered carbon filters so that I can regulate the rate and quantity of water flowing through the carbon filter. There is a sponge filter on the inlet side of the carbon and filter floss on the outlet side of the filter. I also put a layer of phosguard after the carbon so that I have a combo carbon and phosphate filter. Any phosphate being released from the carbon as well as any that is in the bulk water is caught by the phosguard.