Tropical Fish Forums

[mr.elcajon]

So besides my already existing problem of ammonia and nitrites and nitrates. http://www.aquahobby.com/board/viewforum.php?f=8. now my tank has this red growth on the sand and some on the rocks. My LFS said it was a cyno bacteria or somethin. I think thats what he said. I'm lookin it up as I type, just need some more info on it

[FloridaBoy]

It's feeding off the nitrates and/or phosphates in your water.
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 even 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 a great deal, 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.

With reduction of feeding and when combined with nitrate/phosphate reduction, these silicate-based blooms usually grow out and crash in a few weeks.

Like I mentioned before on the other thread, it sounds like something is fundamentally out of order with your filtration, what is your system turnover rate? ... (second time I have asked that question) also is your skimmer producing dark goo in the cup on a daily basis? If not, you may need to clean and adjust until you get results. If your substrate is over 1/2 inch deep I would start slowly reducing it using a siphon---this can be in combination with water changes, the substrate is likely the source of your problem.
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Keepin' marines happy for 25 years

[mr.elcajon]

Thank you very much. I agree. I think the sand is the source of my problems. its too late tonight, but I'm going to take out prob more than half of the sand. my turnover rate is about 550 gph. and I do have a nasty dark green sludgy, gross stuff in my skimmer. but I'm workin on getting a top off system. it should help my protien skimmer run at the correct levels all the time.

[FloridaBoy]

A few more points for you:

1. That turnover rate may be too low for a reef tank, many reef aquarists prefer at least 10X tank volume per hour (rates of 15X--20X are common). You need to get yourself a gallon jug and follow the directions at this link below to calculate your rate. Over a period of a year pumps and filters can get clogged and slow down a lot, so you might not be moving as much water as you think. Generally speaking, water in healthy reef tanks is briskly MOVING, not stagnating---you want detritus and uneaten food to stay in suspension until it is skimmed off and removed, not settling down into your live rock and rotting in your substrate. Remember, many pumps lose a LOT of flow with head pressure, and I suspect you are going to need to add some strategically placed pumps behind your rocks and increase your turnover rate to help this system start "breathing" again. Read these links:
http://saltaquarium.about.com/cs/beginnerscorner/a/aa081399.htm
http://www.aquariumguys.com/aquarium-circulation-article.html

2. Do not stir or disturb the entire sand bed at one time! I would reduce it slowly over several weeks, just a little at a time from no more than 1/3 of the tank at once. Make sure you are REMOVING sand with a siphon and not simply stirring it up.
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Keepin' marines happy for 25 years

[MarkLehr]

Agreed.

I also have found that increasing alkalinity helps in the fight against cyno. I generally suggest raising your alkalinity to 14DKH during these outbreaks.

Why you ask? I can't offer an explanation other than to say I have found it to be effective. I suspect the increased alkalinity encourages coraline growth, which makes it difficult for the cyno to spread.