Dirty Sand-- say what?!

Look what's been forming on the top of my sand recently... say the last 4 weeks or so. They are fine brown dots... over time... it looks like hair grows on it. I have been stirring the sand recently and then sucking it up about an hour later with a 5 to 10 gallon water change; however, the problem keeps coming back!!!

Tank Information:
72 gallon (18 months running)
nitrates, nitrites, ammonia (0)
temp. 78
salinity 1.025
mag 1400ish
cal 400ish
dkh 8-10 (stupid color strips)
I have 4 maxijet 1200's on a wavemaker at different levels for flow
I run a 1/4hp chiller
I do weekly 5 gallon water changes...
I have a cleanup crew with shrimp, hermies and snails...
My fish are listed in my signature area...

I am getting really frustrated... I like a clean look at the bottom...
This never happened before... Do you think it's time to change out the sand?????? Any help-- SUPER KARMA!

Thanks,
Ryan

 

Looks like a diatom bloom to me... have you used tap water for water changes or anything? Change your photo cycle? Add anything with silicates?

 

I've used the same RODI water from the water mill down the road for the whole time... can't be that...
Not sure what silicates are... I filter feed, use frozen and flake foods... at times pieces of raw shrimp...
What in the world are diatoms? Yikes... sounds bad... can it be controlled??

 

Most phosphate removers also remove silicates. Run a phosban reactor to remove the silicates and phosphates and they'll go away.

You need to put some meat on that yellow tang. It's starving. Make sure you have nori on an algae clip daily.

 

I swear I feed that yellow tang daily... it's just the blue hippo is a beast... and attacks that clip more so (I assume) than the yellow tang... I'll keep an eye out.
Where do you put the phosban reactor? I have no room in my sump whatsever with the skimmer and pump for chiller ...
Is this a costly fix?
Is this the result over overfeeding... or just in the water chemistry?

PS I do have chaeto in the sump... that wouldn't cause it... would it?

 

phosphate reactor - Google Product Search

Every time you feed your fish, you're adding phosphorus. MOST of them time, you're also feeding Silicates. Diatoms need phosphorus, silica, and light. That's why the best way to deal with these is to clean the sand (turn over the top layer) and start controlling phosphorus and silica.

 

Cool... thanks for your help!
I would love other people's thoughts and suggestions too!

 

yeah i agree with him. i turned off my light for a few days and that helped too when i had a diatom bloom.

 

I get that whenever i add live rock have u added recently????

 

I have a small diatom bloom from adding 40 gallons more capacity to my system. Nothing else has changed. I put my sump in the basement and a couple days later diatom bloom.
--------Just to have some input here.