blackish algae film on sand???

[incubusboy87]

tank specs:
37 gallon reef (toadstool, xenias, green star polyps)
15 gallon sump 3/4 is refugium with chat. growing
ammonia: zip
nitrite: zip
ph: 8.2
phosphate: tested zero at my work
nitrate: little bit over zero
lighting: probably problem, actinics 12, white 10 hours

hey everyone ive had my tank up for about 2 months now. Ive been battling algae which i understand is part of in immature tank. Ive recently got a clean up crew and all i mean all algae is gone except for this black film on the sand and now spreading to the rocks. Its a solid piece if you try and pick it up, and you can somewhat see through it. What kind of algae is this? or is it some type of bacteria? its spreading so need to figure out how to treat it. My boss gave me e.m. tablets to treat the tank and says it should make it clear up. Im guessing its some bacteria due to the fact my algae blenny, crabs, or snails arent touching it. So suggestions on what it is and how to treat is what im looking for!

thanks!!!!

 

[OrionGirl]

Sounds like a varsion of cyano--manually remove as much as you can, and then see about adding some cleaners that will dig through the sand.

 

[incubusboy87]

ya yesterday i removed all i could actually get my hands on. This morning its back to the same extent it was yesterday. Over night it just regrew. Cyno's just a bacteria of some sort isnt it? So if i get something to turn over the sand it should solve my problem? I have probably 12 nassarious snails in there, there little ones though. probably quarter inch in size. But it seems like they avoid the spots where i have it. The use to burrow in the front were all this stuff is, and now they stay in the back on the tank and burrow back there. My serpent star doesnt really move accross the sand either. What would you suggest for critters to turn over the sand since this is what you think will fix this. Also what creates cyno? not enough skimming or something, or is it just a freak accurance?

 

[reefrash]

Try getting a little more circulation to the areas where the cyano first appears. Do this after removing the cyano as per O.G.'s suggestion. See what happens, I've noticed it seems to be in the chain of events after diatoms, you get cyano, and if your water quality is good just make the sandbed a very unhappy place to be a cyano bacterium.(run on sentence from h%ll right there).