Zeo and diatoms

[freezetyle]

sponge power is mainly silicates. SP would essentially be fuelling your diatoms.

how long have you been dosing Zeostart? if you have been at ulns for a while you may be over dosing and the film that you are seeing might be excess bacteria.

you could cut the SP for a few weeks while everything settles out and your diatoms disappear. or revisit the amount of ZStart your adding