No, if you do water changes, say 50% weekly, the PO4 can never exceed
2x the weekly dosing.

If you don't do regular weekly water changes, then....well, of course
things build up.

If the tank is 5-10ppm of NO3, then howe can you have more PO4?

I suspect bad test kits, don't fret, it's a very common problem and
misconception that test kits are accurate, with NO3 and PO4 being the
worst of the them.

5ppm will not throw off the charts too much, tap water might have some
non bicaronate alkalinity the reads on your test kit.

KH is defined as carbonate alkalinity.

All test kits sold for the hobby are total alkalinity.
Generally they are correct, but often, depending on the tap, they can
be way off.

Many folks simply/progressively slowly add more CO2 each day till they
see fish stess and back off a tad.

I'm sure you can add more based on what you have said.
You can still use the charts also, just add the gas to the tap water
and see what combo you have and then measure the tank's KH.

Adjust for the difference, which is relative.

Say the tap KH is 5, say the tank is 8.
Adjust the pH based on 5, not 8.

This might work for you.
If not, try the slowly adding more method.
Make sure you have some slight surface movement.


regards,
Tom Barr


www.BarrReport.com