Daily diatom algae??

[Christopher311]

Im dealing with what I think is diatom algae. It's brown and covers the rocks and sometimes the sand. It brushes off very easily. What's weird is that every morning it's gone. With the lights off all night it goes away but within a couple hours of turning the lights on it comes back. I'm familiar with diatom algae showing up during a nitrogen cycle but my tank is about 4 months old.

I do weekly water changes and am running a protein skimmer. Water filters through active carbon and purigen. My numbers are all very low.

What's goin on here and how do I control it??

 

[jondamon]

Diatoms are usually caused by silicates.

Could there be silicates residing in your sand bed?

Is your source water for a PWC ROdi?


Jon

 

[Christopher311]

Water is RO/DI. I don't know if there are silicates in my sand bed?? It's aragonite sand and I stir/vacuum it often.

 

[jondamon]

The stirring of the sand could be the cause. There could be residual silicates trapped under the initial layer and by stirring it up is releasing them.

Im no salt water guy but I see 2 possible resolutions but they could be wrong so don't take it as fact but you could either not be so thorough when disturbing the sand or keep doing what your doing and eventually the silicates should get used up.


Jon

 

[Gregcoyote]

Some salt mixes I have found are pretty high in silicates, which IMO does cause diatom growth. It takes really low phosphate levels for diatoms not to grow, but I changed salt and uses a silicate absorber for a while and it went away years ago and only appeared when I stirred up the sand bed. But haven't seen any for years now.