When do you do your WC/ maintenance and what's your levels.

[Aquattro]

I have been doing 50% twice per month. Might cut that in half this year.

Ca 430
alk ~9ish
Mg - never cared

PO4 - aim for 0ppm, 0.02ppm is acceptable.
NO3, aim for 0, apparently nothing in my tank cares if it is closer to 50ppm