Cyano and UV Sterilizers

[Treefer32]

For the past 6 months to year my sand bed was covered in cyano. I used Chemiclean did the appropriate water changes, it'd go away for about a month then came back just as bad. I cleaned up my gyres and got them running better and still no changes in Cyano.

My LifeGard 120 Watt UV sterilizer (running at around 1200 gph for parasites through the sterilizer) started beeping. The countdown timer for the UV bulb hit 1 year, and beeped. So, rather than changing the bulb I turned the UV off for now until I replace the bulb.

My T5 HO bulbs are running on their 14th month. So, I'm a bit behind on replacing those too.
I still have the AI Hydra 52's (3 of them) running at full intensity. Other than a 30-40% reduction in T5 light, I don't know of any other changes. I reduced my calcium dosing due to an over dose (800 ppm of calcium) but it's down to around 440 now, and I've resumed dosing of calcium chloride, just lower doses for the time being to allow things to equalize.

My alk consumption is at its record consumption. I just hit 300 ml per day today. My alk had dropped to 7 dosing 264 ml per day. Plus 1.5 liters per day of kalkwasser.

All of that to say, filtration wise, I haven't changed anything, and noticed really clean smells coming from my tank (I posted about) about 3-4 weeks. The cleaner smells from the aquarium water are persistent. And now my sand bed is nearly bleach white. The cyano just died for unknown reasons over the last 2 weeks (Almost to the day since I shut my UV off).

Was my UV Sterilizer indirectly causing Cyano build up? How do I run UV and not have Cyano issues? Seems odd. But, I can't determine what else is the cause. Unless it's just the perfect storm. e.g. less calcium dosing, 1 water change, and lower intensity light? I just never thought my T5's make that much of a difference in cyano.

I still want to run the UV I'm just scared it's going to pluck reduce good bacteria and increase cyano again. Lol.

 

[Spare time]

A UV sterilizer may remove other microbes that would compete with the cyano.

 

[Randy Holmes-Farley Verified Community Expert]

The bacteria that dies after passing through the uv may also be a source of organics for the cyano. Or it may just be coincidence.

I’ve not heard uv folks complain about cyano more than others.

 

[Treefer32]

Too much in this hobby is coincidence. But too much is too expensive to verify whether something is or is not a coincidence...

 

[Moe K]

I will add to this. I have turned on my UV sterilizer for the last month or two and am having a bad case of cyano also. I have tried a number of things and nothing seems to phase it right now. Usually I noticed cyano likes to pop up when nitrate gets very low or near undetectable but that is not the case right now. I also started running carbon in a media bag consistently.

In this current tank I usually do not run a UV filter at all and used carbon media very sparingly and used to be amazed at the absence of cyano in my tank. A previous tank a few years back I ran UV and carbon media almost its whole life it almost always had some cyano. Maybe there is a pattern.

So I guess there is only one thing to do. I will shut off my UV and remove carbon media and report back in a couple weeks. Please tag me if I forget

 

[Treefer32]

I will add to this. I have turned on my UV sterilizer for the last month or two and am having a bad case of cyano also. I have tried a number of things and nothing seems to phase it right now. Usually I noticed cyano likes to pop up when nitrate gets very low or near undetectable but that is not the case right now. I also started running carbon in a media bag consistently.

In this current tank I usually do not run a UV filter at all and used carbon media very sparingly and used to be amazed at the absence of cyano in my tank. A previous tank a few years back I ran UV and carbon media almost its whole life it almost always had some cyano. Maybe there is a pattern.

So I guess there is only one thing to do. I will shut off my UV and remove carbon media and report back in a couple weeks. Please tag me if I forget

Looking forward to hearing of your results @Moe K ! I can't believe how pristine my sand bed looks. My rocks have some red on them but that is dissipating too. I always have nitrates - between 10 and 20 now. Rarely do I get them below 15 to be honest, nor do I try. When I do my 50% water changes I might get them down to 5-10 but never 0 not with my dirty large fish.

I am planning to replace the bulb in the next 3-4 weeks and turn the UV back on as I plan to add some fish and don't generally QT.

 

[Siegfried]

I'm going through cleaning up a major cyano outbreak. I'm convinced it started right after I did major cleaning (probably too much sand substrate disturbance and glass cleaning at once), which followed by a major cloudy water outbreak for several days. I read, this can be cleaned by using a UV light, which I enabled (unbeknownst or for the lack of better experience and knowledge) for 3 days non-stop on. After 3 days the tank looked completely clean, but a few days after this, a major cyano outbreak took hold. From studying, this is obviously due to eradicating "bad" + "good" bacteria. Following completely divided Internet forum communities on how to deal with this, I chose to treat this with Chemiclean, because of the weeks longs established deep red and purple mats, covering most of the substrate and completely blanketing the rocks. 48 hours later, I see some red/purple colors being replaced with white, mostly on top of the rocks, but the sand substrate shows no difference at all.

This is a very basic (beginner's) 40 gallon breeder salt water aquarium tank with a pair of clownfish, a few chromis and a corral banded shrimp, and a snail.

My question is, again, after studying what appears to be a very divided set of internet opinions on how to deal with Cyanobacteria outbreak:

Should I treat a second dose, since not much difference after 48hours (again, major outbreak, all rocks covered in slime mats, sand bed with 50+ patches of pink and red, can't siphon anything because it drops right back to bed) or should I avoid a second dose, and switch strategy: I have amphipod container and copepods, as well as fresh phytoplankton on the way.


Thanks so much for avoiding general responses. I probably already read 50 times over, reef2reef posts, multiple other sources, but I am not finding a general consensus. It seems most experienced reef folks are either calling Chemiclean a reef husbandry failure, or newbie tactic, whatever it is, I want to learn and have a more scientific understanding here, not political opinions.


I would kindly ask, if you post a generic comment or general reply about his issue, to include references, that I can study. I don't want a "I have always done this for 25 years and that worked for me" solution, I'm looking for scientifically oriented responses that will help me get a better understanding of some of the most experienced opinions of how to deal with Cyanobacteria, caused by a complete "reset or reboot as described in these forms" because of the UV sterilizer that was probably overused in running 24/7 for many days.

Thank you!

 

[Randy Holmes-Farley Verified Community Expert]

Welcome to reef2Reef!

I'm not sure there is as much incorrect info about cyano as there are just different approaches, all of which may work in some circumstances. But there is clearly some small amount of misinformation relating to nutrient levels.

My recommendations for dealing with cyano are to reduce organics (and not dose them), manual removal of the cyano (better than killing them with antibiotics) and higher flow.

The rationale is that cyanobacteria are bacteria that can thrive on organics, including dead bacteria (the UV) and dead cyanobacteria (chemiclean). Manual removal removes the organics in their bodies.

Antibiotics clearly work, but it can also come back.

 

[Randy Holmes-Farley Verified Community Expert]

Bottoming out of bioavailable N (ammonia, nitrate, urea) with a cyano problem may not be desirable because cyano is one of the few reef organisms that can get N from the air (N2).

 

[Siegfried]

Thanks so much for your feedback Randy. My Amphipods and Copepods arrived today, I'm going to research if I can keep these in the container they came in for a few more days, and if that is the case, I may try another dose of chemiclean as well as try to manually remove more cyano. Siphoning does not work at all so I'll try to brush or turkey baste what I can off the rocks.

 

[DannyGT]

Interesting. I bought a drop-in UV for my 40G tank to tackle a very cloudy bacterial bloom. There was a tiny patch of what I believe to be cyano on a rock at the back. The UV worked wonders and made the water crystal clear. After I removed it, the bloom reappeared a few weeks later. I put the UV back in, and within 2 days, the water was crystal clear again.

However, I performed a water change and did a very light surface cleaning of the sand bed. Since then, I've kept the UV running 24/7. While the water remains crystal clear, the cyano seems to be spreading. Could this be a coincidence? Parameters are all in line...fish, etc are all healthy. I only feed once in the morning, and its enough for them all to eat and leave very very little leftover. Have a decently large CUC too.

Are there any livestock known to keep it at bay?