Originally Posted by Gregcoyote
zero might not be zero. As I mentioned it is really hard to see those smaller readings with a color check test kit. Something is generating the Cyano
and phosphate can be one of the causes.
I just bought a RODI
And did a huge 50% water change to see how much of a difference the RO
water makes .
I'm thinking the Phos was coming in with the water I was using .
I did test nitrates in the water I was using a couple months ago .
The water tested at 10ppm before it even entered the tank .