what is on my sand

[egon]

could someone please help with what may be growing on my sand. it is a brown mat like substance with a few redder patches dispersed throughout it as you can see in the picture. the tank has been in its current setup for about 1 and a half months. the tank is 90 gallons and has 180-lbs of live rock with a 5 inch deep DSB. for water i have used only distilled water, as i am waiting for my ro/di unit to arrive.

water conditions are
ammonia 0
nitrite 0
nitrate 0-5
phosphate 0.1
ca 450
alk 11dkh

 

[egon]

also can anyone tell me why the picture showed up 4 times...still trying to learn what i am doing

 

[fishfreek]

Well the first is where you linked the thumbnail from a photo you uploaded to the gallery. The other three is where you tried to attach the photo to the post. There is a slight bug in our attachment feature that cant be resolved till a new version of our forum is released.

I would venture a guess that its either cyano or diatoms. The redish color has me going toward cyano. Does it cover stuff in sheets? What kind of water flow to you ahve in that area?

 

[Guest]

Looks like diatoms to me. Ive had no problem with it since getting my new Palani tang. He eats it and the sand, also eats cyano 8O

 

[pecan2phat]

I constantly had this problem for years. (Cyano that is) My tank was a heavily loaded FO tank and the NO3 & PO4 was not high either. 10-15ppm for NO3 and .02 ppm for PO4.
Well, I decided to purchase a RO-DI unit back in 12/03 and have performed 15 to 20% water changes bi-weekly and my cyano has been gone for about a month now. I'm a true believer of RO-DI makeup water now.