Brown algae after starting ozone... help

OC CJ

Crushed coral > sand
My tank has been up and running for abot 1.5 years and I decided to give ozone a another try after not running it for 5 years.

Tank had no algae problem and I only ran aquamaxx all in one filter media.

Since using ozone again i've seen a brown algae bloom on the sand every day and my fuge broke out in cyano. Don't remember this happening before.

I'm running the ozone 24/7, not to exceed 420 orp. My generator is running about 35mg/hr. Been running this way for about 2.5 weeks.

Other than removing the aquamaxx media in place for an ozone carbon post filter, i haven't changed anything on the tank. I don't remember this happening the last time i ran ozone.

Params are stable with nitrates undetectable and phosphates at or below .03.

What am i missing? Is this typical when first starting ozone? Any feedback would be greatly appreciated.

Thanks,
CJ
 

Randy Holmes-Farley

Reef Chemist
Premium Member
It's not "normal" but I can imagine how it might happen by making some organics more bioavailable and/or breaking them down into inorganic nutrients. If true, that effect will dissipate.

More often, people see a reduction. Here's the relevant section from my ozone article:

Ozone and Problem Algae
Many aquarists report a reduction in problem algae when initiating ozone, although it is not universally observed. Whether it happens in my aquarium is one of the observations that I will report in the third article in this series. However, more people report it than I would expect if it were a simple placebo effect, where new users might be looking for a decrease in algae, so they "see" it. How might algae be decreased? The answer is not clear at all. No clear explanations were provided to me when I asked very experienced chemists who have used ozone in aquaria for many years. Nevertheless, this section provides some potential causes.

As described above, ozone breaks large organic molecules down into more bioavailable fragments. Perhaps using ozone to drive that process increases the rate of bacteria growth in the aquarium, and the bacterial growth consumes nutrients just as happens when aquarists dose organic carbon sources to aquaria to drive bacteria. This process would be related to the decrease in skimming, where organic molecules are no longer as effectively skimmed out. Where would they go? Into the hungry mouths of bacteria that then multiply faster, and consume nitrate and phosphate in order to produce the biomolecules of life (proteins, DNA, RNA, phospholipids, etc.).

Another, vaguer, explanation has to do with the ORP itself. It has been suggested that increased ORP hampers the growth of microalgae relative to macroalgae and other organisms that aquarists maintain. There may be a bit of the chicken vs. the egg argument here, where it is not clear if the lower ORP drives the algae (by altering the availability of metals such as iron, for example), or if the algae drives a lower ORP (by releasing large amounts of organic molecules, for example). In any case, raising the ORP may well alter the bioavailability of important metals such as iron. In fact, even without raising ORP, ozone may break down strong metal/organic complexes, increasing the bioavailability of the metal. In either case, ozone may tip the delicate balance of nutrient flow away from microalgae and toward other organisms (macroalgae, bacteria, corals, etc).
 

OC CJ

Crushed coral > sand
Thanks Randy. I re-read your articles before starting up and was surprised by the sudden outbreak. Didn't happen the first time I ran ozone.

I've backed down my ozone a bit to a constant 25mg/hr and lowered my ORP to 400. May be a case of increasing it too quickly. Maybe it was ramped up to fast, breaking down organics faster than the rate of bacterial growth.

If that's the case, hopefully backing it down just a bit and letting things "settle in" the issue will resolve itself.
 

reelredfish

New member
Did you continue to use ozone?

Randy I had read you stopped using ozone? May I ask why? I was thinking about setting up ozone on my new 180.
 

origreefer

New member
I've been using ozone for decades and can't tie cyano forming to it's use. I was in the military so moved often and was always setting up a new tank every few years, this is when cyano outbreaks occurred. I used o3 at startup, after tank stabilized cyano disappeared. However, my ORP was (and is now) in the 350-380mv range. I'm just speculating but perhaps you are using too much to get to 420mv level.
 

Bilk

New member
Is it possible the ozone reduced the bacterial population, disrupting the uptake/export of nutrients?
 

origreefer

New member
Is it possible the ozone reduced the bacterial population, disrupting the uptake/export of nutrients?

Makes sense. I have an industrial ozonizer at work I use to kill bacteria in sporting equipment. It's high concentration. I suspect the OP is using too much for his 50gal tank. 35mg per hr I think is too much. I'm suing 10mg on my 75G.
 

Randy Holmes-Farley

Reef Chemist
Premium Member
Did you continue to use ozone?

Randy I had read you stopped using ozone? May I ask why? I was thinking about setting up ozone on my new 180.

I stopped using ozone out of concern about HLLE in hippo tangs and a fin issue seemingly related to HLLE in yellow tangs. It was suggested to me that it might be contributing.

I also switched to a better brand of GAC (and don't use the large amoubnt of GAC I had to break down the ozone) at the same time (now using ROX GAC), but whichever it was (if either), my current yellow tang has no such issue. :)

I do once in a while (less than once per two months) run a small amount of ozone into my skimmer to help reduce any yellowing compounds that have accumulated. I run that about 18 h, then stop.
 
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