Dirty Sand

[chuckdaddy154]

Hey guys,
I have a 90 gallon tank stocked with 5 fish,90lbs of rock, a sump with a protein skimmer. Just did a water test and show zero ammonia, zero nitrates, zero nitrites, zero phosphates, 8.4ph. The problem is algae all over the floor of my tank which won't go away.
I do a weekly water change with RO/DI, as well as auto top off with RO/DI.

Any advice on how to get rid of this algae? I attached a picture of what it looks like.

Thanks!


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[BigRedsReefs10]

Cyano, either excess nutrients in the system or low flow zones where detritus settles. Reduce your feedings and siphon as much as you can with your wc's.

 

[chuckdaddy154]

I clean it all up after every water change, but it comes right back. Do you think adding a 3rd powerhead would help?

 

[BigRedsReefs10]

It might

 

[buxndux]

I'd try the third power head. What's your gph rating as of now?