I've been battling a GHA outbreak, and I think I'm winning. With the weekly water changes I have been stirring up the sand real well to get all the crap out. When I'm done with the water change and everything settles I get this light grey dusting over the sand. over the next few days it will slowly turn dark brown and look nasty.
I use nothing but 0TDS RODI
water and I have 0 nitrates when I test with the API master kit. What can I do to stop this from happening? I have one Koralia nano 240 ph in a 29g biocube (soon to be 125g).