Diatoms? Dinos?

[CookieRdReef]

What do I have here? I have had some brown algae on the sand bed which now looks stringy and is on some rock work too. Tank is 7 mths old. I recently had some high PO4- .15ppm and NO3 25ppm. Prob high silicates from RODI not working for 2 water changes but now back to normal. Thanks for the help!

 

[SteveEreef]

The first picture looks purple to me - Cyanobacteria

 

[vetteguy53081]

+1 cyano

Siphon up gravel and check Phosphate level.
Are you using Tap water ?

Also_ ChemiClean is a very good and safe product to erradicate this

 

[CookieRdReef]

Thanks! I will try the chemiclean. Using RODI water and RODI unit is giving me 0tds now.

 

[SifuMemphis]

Try to increase your flow also.

Ideal range for Nitrate is 10-20 and phosphate 0.03-0.08