Brown-Yellow Filth on Sand

[FriscoTX]

I did a pwc yesterday and vacuumed the sand bed to get rid of this brownish yellow stuff growing on my sand. Can anyone tell me what it is and how to get rid of it long term?

Ammonia 0
Nitrite 0
Nitrate 0
Phosphate .3
PH 8.3
SG 1.025
Calcium 440

 

[ezy33]

Lighting?

 

[melosu58]

Is it dusty or slimey?

 

[FriscoTX]

It looks more dusty than slimy - i'll try to get a picture up later this eve

 

[roka64]

How old are your lights? What kind of clean up crew do you have?

 

[FriscoTX]

EDIT: lights 2 pwc 24watt, 1 actinic, 1 10k - it's a 2 month old bio cube
clean up crew is 4-5 hermits and 4-5 snails, i can't remember since I bought it as a "clean-up crew" from the lfs

 

[roka64]

It sounds like diatoms, but a pic would help.

 

[melosu58]

It sounds like diatoms

This would be my guess also.

 

[loyalrogue]

Well now that the veterans have agreed, I'll be bold and say that it sure sounds like brown and golden diatoms to me too.

What kind of sand did you use to start your tank?
Diatoms like silicates.
If there's a source of silicates in your tank (sometimes from sand, water, or salt) you'll have to remove it.
Other than that you can starve it just like other types of algae or cyano.
Reduce your lighting period, and reduce the excess nutrients in your tank.

 

[FriscoTX]

Here's a picture - Do I have any excess nutrients? Unless you count po4 which is still on the low end, I would think my nutrients are good. Is 48 watts and a 10.5 hour daytime schedule too much light? Also I have the outflow pointed up to maximise surface movement, should I have the outflow directed at the reef itself? That could create more flow down at the base - just a thought.

 

[Dr.Nate]

More flow in those areas where it is accumulating will definately help, but I believe the real issue is the P04. You should ideally have not "low" P04, it should be 0. The best way to get there is to do multiple PWC's with Ro/Di water.

The reason that I say this is because if you're testing "low" for P04, these diatoms could be consuming what is there and in actuality your reading could be much higher. Also, a more accurate po4 test would be beneficial that gives you a specific reading (I use salifert)

HTH

 

[roka64]

I definitely agree, you want to shoot for 0 on phosphates. More water flow to those areas will help also.