Richard Sexton wrote:

Just had an idea. I'll check against my dehumidifier water.


Not relally a good idea, dust, which is mostly skin cells,
gets in there and goes through the nitrogen cycled and becomes
nitrate.

Distilled water from a store is your best bet.

Damn, you're right. The dehumidified water contains absurd amounts.
Checked against two test kits: over 20ppm!!

Rain water gives 4.5ppm with my Hanna and 1ppm with Salifert.

Yes, I'll get some distilled.

Nikki