Phosphate in Fritz RPM

[Betta2]

I tested my marine tank for phosphate using an API Reef Master Test Kit and found a concentration of 0.50 ppm. Curious as to why it was so high, I prepared a gallon of saltwater from Fritz Aquatics Reef Pro Mix and found a concentration of 0.25-0.50 ppm. I tested the RO water from which it was prepared and found a phosphate concentration of 0 ppm.

Please comment.

 

[blaxsun]

Get a better phosphate test kit.

 

[polyppal]

The salt won't be the source, PO4 generally comes from organic decay (fish/coral food, poop). Prob a false read.

 

[polyppal]

Get a better phosphate test kit.