Tropical Fish Forums

[tripwater]

I have read and read many posts and articles about cyanobacteria and I am doing my best to get rid of the outbreak that is in my tank.

My salinity 1.025 temp 78-79
pH 8.4
amm 0
nitrite 0
nitrates 15
phosphates .25

I am doing regular water changes using DI water, I am scrubbing off as I siphon, my phosphates are at an all time low, I took my lights to 9 hours a day they were 10-12. I don't know what to do or what I am doing wrong. I stopped supplementing as much about 2 weeks ago, got a skimmer about a month or so ago and even after all this, I have no idea what to do next. I have a normal compacts that are 2 X 65w 10k and 2 03 blue actinics 65w each.

I even cut back on feeding my fish to help with the phosphates (which have dropped ).

Any ideas? I am really tired of looking at this red crap all over my rocks and various coral.

Thanks

[tripwater]

oh and I also went out last week and bought 25 more blue legged hermits and 4 more snails to help out...

[FloridaBoy]

It's feeding off the nitrates.
Funny thing about that is, you are getting a false reading on your nitrate test, because the bacteria is consuming the nitrates. If you were to remove the cyano, your actual nitrates would be even higher. You need to find out where the nitrates are coming from, usually related to a stagnant substrate which has become a nutrient sink.

To my knowledge, snails won't eat cyano, crabs are not a silver bullet either. Water changes can help, however make sure you're not adding more dissolved organic compounds (DOC's) with these water changes, many cities have surprisingly high levels of nitrates and phosphates in the tap water. RO water helps, but some RO units will only remove 80 or 90 percent of the nitrates, please research.

This material can and should be removed with elbow grease and a siphon, it's not that hard to do, and may be required until you sort things out and lower those DOC's. A small diameter rigid tube attached to a siphon hose works very well. Make sure you are REMOVING the material not just redistributing and spreading it throughout the tank. If the cyano persists long term, you may need to look to competing macro algae in a refugium to help reduce the fuel these bacteria are using.
Try to avoid chemical/antibiotic treatments at all costs.

You're on the right track with reduction of feeding and when combined with nitrate/phosphate reduction, these silicate-based blooms usually grow out and crash in a few weeks. How long has the tank been set up?
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Keepin' marines happy for 25 years

[tripwater]

Thanks. The tank has been setup for about 2 years now. I have had this happen before but not this bad. I added a good bit more live rock and so it is hard to get to the substrate to stir it up. I usually let my gobies do that for me because my siphon won't reach in many places between the rock and glass.

Thing is I have about 3-4 inches of sand in my tank. I went with a thick substrate in the beginning for burrowers and to give more of a cushion and hold for my rocks. The gobies have moved things about a good bit but I wonder if it is the fact that I may have too much sand with nutrient build up?

[FloridaBoy]

Could be, in my opinion MOST long term marine system failures are due to substrate issues. 3-4 inches is in "no man's land," meaning it's not a thin bed and it's really not a deep sand bed either. Most marine aquariums fall into this category, and they can produce a surprising amount of DOC's. Once they become a nutrient sink no amount of water changes will help for very long. This is very common. I suggest you SLOWLY start reducing the depth of that substrate, siphon a little out every month with your regular water changes and discard. Be careful do not disturb a large area, do it a little at a time. Get it down to about 1/2 inch and see what happens. Many successful reef tank have minimal substrates or even bare bottoms.
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Keepin' marines happy for 25 years

[tripwater]

OK, will do. Thank you for your help and time

[Psyfalcon]

Cyano also like areas of low water movement. Upgrading your current, or redirecting powerheads towards the biggest offending areas can be effective at treating the symptoms while you're also working at reducing your nitrates.

When I had my FOWLR nano, I repositioned the powerheads regularly to take care of any problem areas. Even in my freshwater tanks, just moving rocks away from the glass can increase water movement, and reduce some cyano.
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