07-11-2019, 08:20 AM
Join Date: Apr 2005
Location: Brentwood, CA, USA
iTrader Positive Rating: 100%
| | Re: Phosphorus and Phosphates
As a general rule, you have to follow the instructions that come with a test kit, exactly as written, or you can't rely on the results of the testing. But, I have no experience with measuring phosphates, so I don't know the answer to your question.