What is this yellow stuff growing on my live rock?

[colonelgreen92]

not sure what this is. It bloomed after a big water change. The tank has been up 8+ weeks and this came out over the weekend. The rock was curing for 13 weeks, started with a 2 week cycle of bleach solution then 11 weeks with just salt water changing the water weekly. Please help.

 

[dwest]

That some yellow stuff! I’m guessing diatoms if it blows off easily and possibly chrysophytes if it’s more globular. Either way I wouldn’t worry now as the tank is maturing.