What is this in the sand?

Cyano is more likely as I have never had any problem with diatoms in 30 years lol. They usually quickly dissapear. The fact you are using tap makes it even more likely. Cyano doesn't start forming bubbles until it matures.It could also be just a brown algae.Do you know your phosphate/nitrate levels?

 

I had my water levels tested last Saturday. Nitrates were normal and i do think phosphate was low...

 

I had my water levels tested last Saturday. Nitrates were normal and i do think phosphate was low...

 

Using tap water will more than likely cause you many algae problems in the future. The 2 best purchases I have made for my set up is the RODI unit and the ATO.

What are the numbers for nitrate and phosphate?

 

i don't remember exactly what the number were. but the nitrate was normal. the phosphate was low I will get them tested again tomorrow on my way home from work.