or you could just make sure that your reservoir is the correct temperature (68-72), the ph is correct, and give it a few days like you did before and it will go away.

Also, if you are using an airstone, be sure you clean all the shit out of it during EVERY reservoir change (this might help, I had to ditch my airstone and just use a small pump to keep the water circulating but the foam thing hasn't happened since).
TMusic Reviewed by TMusic on . HELP i have a white foam buildup on top of the water in my DWC Res..??? Ok i have a white foam buildup on top of my res water....there isnt too much of it but its on my roots now..and i dont know what it is....It happened a time before and went away in a few days...so idk what it is??? i am using GH 3 part nuts. and water from a local spring with a PPM of 220...someone have any suggestions or ideas?? Rating: 5