Backyard Aquaponics
A place to discuss aquaponics

The guy I was talking to today in Chiang Mai said that the water here is very high in Phosphorus.
This is especially true with well water and river water.
A kind of brown scum forms around taps, toilets etc. etc. (my house water is well water, not considered suitable for drinking)

Is it toxic to fish? If so, more so to specific species? (Google didn't help here)
Can it be off gassed before topping up? (Google didn't help here either)

I'm thinking I may have finally found an answer to my dying Catfish.

Too higher concentrations could be a problem... it would certainly promote continual algael growth... and probably mess with your pH accordingly...

Mess with pH? Up or down? My top-up is always high, 8+
Should I put top up in a tank and bubble it for 24 hours before adding to the system?
Phosphorus is something that is rarely talked about with fish, at least from what I can find.
I can't test for it, so I am going on hearsay from "just some guy I met"
He didn't try to sell me a phosphor reducing product though, so I guess he may have been being straight