Rebound effect from Ozone? Stinky?

[Greg Hiller]

I recently stopped using ozone on my system. The ORP levels were getting higher than I was comfortable with >460 mV, and a few corals look a little funky. I had tried turning the levels down, but even with the ozonator at the absolute lowest level where it was on, the ORP was not dropping back down.

Anyhow, in the 10 days or so since I turned the reactor off I've been having some...well...odor problems with my tank. Nothing has died, but I'm smelling a lot more hydrogen sulfide (H2S) around the sump, even near the tank upstairs. I can never remember having a problem like this before. I put some extra carbon on the tank, but it doesn't seem to be helping much.

I thought about this for a while, and the only thing I can think of is that while the ozone was running, maybe in the sand bed of the tank, the redox potential was a bit higher, down to lower depths in the bed.

Let's suppose, and I have no idea of the actual numbers on this stuff, that prior to running ozone, at a level of 1 1/2 inches down into the bed, the redox was low enough (anaerobic) that H2S would be formed. It would diffuse up though the upper layers of sand (where the O2 levels and redox were higher) and bacteria there would convert it back to SO4 (sulfate) so not a problem, ie. no smell.

While using ozone though, maybe the zone for anaerobic activity (H2S formation) was pushed further down into the sand bed....maybe from 1 1/2 inches to 2 1/2 inches?

Then, when I turned off the ozonator, the aerobic bacteria that had slowly migrated and proliferated into the lower and lower levels in the sand bed, were suddenly in a place where they could no longer survive (O2 too low). These bacteria died quickly, and, being in an area of H2S formation, made a lot of H2S when the anaerobic ate them. The H2S diffusing up was coming too fast for the normal upper layer of the sand bed to convert it back to sulfate (SO4).

So, am I full of it? I really have no idea, but I sure would like my living room to smell better soon.

I’ve noticed that many people turn their ozonator on for periods of time, then off again. Anyone notice a hydrogen sulfide smell when the ozonator is off?

[ReeferMedic]

I overdosed my system with ozone over the summer. I lost all my starfish, limpets, a few tigertail cukes, most of my snails and hermits. I also lost a couple of lps I attribute to the over dose. Now, I run it sporadically. The asterina stars and the limpets have returned. I was not running it over carbon. I'm sure that had alot to do with the deaths as well. I have added a few serpent stars and some of those "honkin" big snails from the meeting(thanks CRA), and they all are doing well. I never noticed any stink after a shut it off though. I had it completely turned off for a few weeks before running it the way I am now. I'm planning on getting a seperate reactor for the ozone and run the output over some carbon.

[Yaktop]

So, am I full of it?

easy target :D

you have such a large system, fairly new, no excessive buildups in the sandbed. You can run up to 15ml of ozone for every 25 gallons safely. I've used ozone on and off on occasion at pretty high levels to rid some nuisance algaes and never had any smell other than some residual ozone smell out of the skimmer. The higher end models have an orp probe to shut the generator down as you know and assume you dont have one of these kind. I ran two orp probes one for the generator and one pin point and it gave me a better idea where the orp might be. never ran mine up that high so not sure but then again 460 really isnt that high for the amount of time you ran it anyway.

good luck.

[JD46]

I have never had any mysterious smells when I am not running ozone. When I do run it, I stay at fairly low levels (~50mg/hr and no air dryer). Also, my orp rairly reaches 375. It usually stays around 360-370.

[Greg Hiller]

>you have such a large system, fairly new, no excessive buildups in the sandbed.<

It is a large system, but there are some pretty big fish and corals and I feed pretty heavily. The system has been set up now for 2 years. Also (should have mentioned earlier I guess) that there is an old 65 gallon with it's many year old sand bed attached to the same system.

Interesting that no one else has experienced. Might have nothing to do with the ozone.

[reefkeeper2]

Greg, I wonder how the ORP in your tank gets so high using so little ozone. I run my ozonizer full out 24/7 and lately it never gets above 375 even with the air dryer. It's a 200mg unit. Where do you place the probe? I did a few experiments with probe placement and found where you put it really matters. I now have it just below the water return from the tank. I got the lowest numbers there. Anywhere near the water outflow of the ozonizer brought it up considerably.

[Greg Hiller]

I just put the probe in the sump. It's not too far from the skimmer where the ozone is going in, but even with the ozone off for many days, the number has not fallen much. Maybe the probe's calibration has drifted. It seemed to be working fine initially.

[ReeferMedic]

I just put the probe in the sump. It's not too far from the skimmer where the ozone is going in, but even with the ozone off for many days, the number has not fallen much. Maybe the probe's calibration has drifted. It seemed to be working fine initially.

When the go off calibration, the usually read high ime.

[reefkeeper2]

Calibrate the probe and drop it in the tank, not the sump. See what you get.

[SALTYOLDDOG]

Use UV its safer for You And the Tank

it’s much more controllable
and safer to handle

I use ozone only in extreme cases
too many side effect with medication bio filters etc etc

most wholesalers and retails prefer quad UV over ozone

[Greg Hiller]

Not the fault of ozone. So much for all that BS I wrote above!!

I finally figured out the problem, partly becasue the smell is no longer so much hydrogen sulfide as it is a burning smell. Turns out it's coming from one of the two deep cycle marine batteries that I use in my battery back up system. This morning I saw a slow stream of smoke coming from one of them. Batteries contain sulfuric acid and some reaction or the other was initially forming hydrogen sulfide.

Man am I glad it was not coming from the tank.

[SALTYOLDDOG]

very good glad to hear you that you figured it out
ozone has a sweet sceat too it
too bad about the batteries
sound like they where being over charged

[Aquaman_68]

overcharged or undercharged battery = rotten egg smell!!!:p

[Greg Hiller]

I had two batteries on this system, both wired together, both deep cycle marine batteries. They were about 2 years old. I don't know why the system would have overcharged them. When I opened the tops of the batteries and looked in, the good battery had 6/6 cells full to the top with water. The 'bad' battery had 2/6 filled, and the other 4 partially MT, and at least one of them smoking (I waited until it stopped smoking to open it up). Also, in the FWIW category, I was surprised how warm to the touch the 'good' battery was when I disconnected it.

[SALTYOLDDOG]

YOU SHOULD CHECK THE OUT PUT OF THE CHARGER FIRST
WITH A AMP METER
IT SHOULD JUST BE A TRICKLE CHARGE FOR A deep cycle marine BAT

STILL SOUNDS LIKE ONE GOT COOKED IF THEY ARE WIRED TOGETHER
IN PARALLEL IT MAY BE WHY ONLY ONE GOT DAMAGED

COULD BE ONE WAS JUST LOW ON WATER
ALSO KEEP THEM UP OFF OF THE CEMENT FLOORS

YOU SHOULD METER THE WHOLE SYSTEM TO BE SURE
IT IS STILL FUNCTIONING CORRECTLY

LET ME KNOW IF YOU NEED HELP DOING THAT

SEE YEAH

[Aquaman_68]

I had two batteries on this system, both wired together, both deep cycle marine batteries. They were about 2 years old. I don't know why the system would have overcharged them. When I opened the tops of the batteries and looked in, the good battery had 6/6 cells full to the top with water. The 'bad' battery had 2/6 filled, and the other 4 partially MT, and at least one of them smoking (I waited until it stopped smoking to open it up). Also, in the FWIW category, I was surprised how warm to the touch the 'good' battery was when I disconnected it.
Battery should not be warm ......charged up or not...Sounds like the charger is putting too much amperage back in....Could be the reason one had dried up cells.....
Joe gave alot of sound advise....

FWIW...Deep cycle batteries are made to be drawn down... They don't need to be constantly charged up continuisly with a "trickle charge" They are not at all like a conventional car battery...When you discharge a reg wet cell battery frequently it causes the electorlite in the cells to "die" or others may call it....."dead cell syndrome"

Some conventional batteries are worst or in others words...not too forgiving being drawn down.....They fall flat quick & become useless....

But your deep cycles...are made for this application....IE: campers, moterhomes & boats....They are made to be drawn down in their charge ( a deep cycle is also made to hold a charge while being drawn down longer without the need for constant recharging. They have more lead plates....
Provided the charge is not a constant 24/7 & a large draw in current the DS does not need a constant trickle
The charger just needs to be activated when the battery gets below a preset voltage...
Deep cycle are made to do just that...Be drawn down on the charge....

BTW....What are you using to recharge them & also what are they online for? Just back ups in case of a power outage?

[JayM]

The other reason for a warm battery while under charge is if one of the 6 cells is a dead short. This also means the battery is junk, and needs to be recycled and replaced.

Glad it wasn't ozone loose in your house...

[Greg Hiller]

I was using the battery backup to power one of my recirc pumps in event of a power outage. It works for about 16 hours with a pair of the batteries. I was using the Tripplite voltage converter/battery charger/relay. I wrote an article about the whole thing a while back. The link is below, for some reason the photos are messed up at the moment, might be a problem with Reef Central.

[mandrake]

I dont see the link, could you try again I would like to check it out .Thanks

[Dave McReeferson]

The link is below

No link. ;)

I agree with Jay and Brian, either there is a problem with the charger or there is a problem with the "good" battery, some diagnostics are in order before letting that setup run unattended again.

[Greg Hiller]

Opps, sorry the link is here, got sidetracked. The link with photos should work now.

http://reefkeeping.com/issues/2006-05/gh/index.php