Hey running a 40G rdwc system using cultured solutions for nutes. Curious if anyone else ever has any white foam on top of there water ever. No smell. Just foam and maybe a little brownish residue on sides of buckets above water line. Not a new system but was bleached and cleaned before this run. Did notice on last run also now that I think about it. Any one have any ideas or ever have this. Thansk in advance.