What is this?

[rushopkins]

Weird brown stuff growing in one spot. Pics attached.

 

[KeithFrancis]

Diatoms! Or brown algae...how old is your tank? Diatoms are feeding on nutrients in side the tank such as silicates etc..try reducing your light each day as well as cut back on feeding.
may want to increase water circulation and add a power head as well.

 

[rushopkins]

Diatoms! Or brown algae...how old is your tank? Diatoms are feeding on nutrients in side the tank such as silicates etc..try reducing your light each day as well as cut back on feeding. may want to increase water circulation and add a power head as well.

5 months old

 

[rushopkins]

Diatoms! Or brown algae...how old is your tank? Diatoms are feeding on nutrients in side the tank such as silicates etc..try reducing your light each day as well as cut back on feeding. may want to increase water circulation and add a power head as well.

I don't have any fish in the tank so I only feed the cleaner shrimp every other day a few marine pellets and run the light 5 hours. I have two power heads for water circulation.

 

[KeithFrancis]

I used a compound silicate remover I bought from my Lfs. Any nutrients diatoms will feed off of. Quite normal in a newer tank, be patient and it will die off to healthier, Coraline algae one would hope.

 

[rushopkins]

I used a compound silicate remover I bought from my Lfs. Any nutrients diatoms will feed off of. Quite normal in a newer tank, be patient and it will die off to healthier, Coraline algae one would hope.

I've been using tap water in the tank so I'm sure that was a big problem. My last water change I used premixed sea water so maybe I can get it right finally.

 

[KeithFrancis]

Let me know how you make out, every municipality has different levels of heavy metals. Where I live it's around 165 ppm
I've never used ro/di water, only tap water..all water parameters fine