Interesting Source of Excess Phosphorus..API Posting...does not appear for 24 hours!


Prolific Poster
Nov 27, 2011
Sarasota Florida
I just saw an article on the Facebook page for API. This is what they said

"Secret Source Of Phosphate In Your Tap/Mains Water!
Aquarists know that water can often contain chlorine and chloramine. But some water treatment facilities add phosphate-containing chemicals to the water. Why would they do that? These complex phosphate treatments prevent new corrosion, dissolve existing corrosion and provide a protective coating in metal pipes. Here at our US lab our tap water contains very little phosphate "out of the pipe." But in 24 hours the same water sample has a jump in measurable phosphate. It turns out our water supplier adds a phosphate treatment. This phosphate cannot be measured with aquarium-style test kits. After about 24 hours the phosphate complex breaks down and can be measured with a test kit. Under the right conditions an excess of phosphate can trigger an algae bloom. If your aquarium gets an algae bloom after each water change it may be caused by the extra phosphate."

I've always wondered why mine has none and is lower but then after a few days it spikes. Now I suspect this is what my local water treatment facility is doing. Hmm. How annoying. The problem is I'm not sure it's really all that good of a quality of phosphorus as I'm currently adding it to my tanks and the plants are doing better. It still registers high....but no major algae issues are occurring now that I've reduced my hours of lighting to 8 per day. Anyway, I thought it would be useful to spread this news only because some of you may need to test after 24 hours to see if this happens.