I'm seeing my name bantered about, so I guess I should comment!... But lando and MsBeanCtr already stole my advice - replace your DI
resin. If you're showing any amount of phoshpates coming out of your RO
unit, then the DI
resin isn't doing it's job. Even if the RO
membrane wasn't doing a single thing, the DI
resin should at least give you pure water... for a while. Also, when DI
resin is depleted it can actually leach contaminants back into the water. So in theory, you could have worse water coming out than going in.
So the easiest thing is to replace the DI
resin. The phosphates should go away and your TDS
readings should be 0.0ppm. If within a short time the phosphates reappear and your TDS
goes up, that implies that the RO
membrane isn't doing it's job and your DI
resin is doing all the work - at that point you should probably replace the RO
And I agree... looks like cyano
, not diatoms. Nice lookin' Open Brain, though!