How Much Po4 Actually?


Lifetime Member
Lifetime Member
Jun 3, 2013
The cup test sounds good. I just thought it a little suspicious that you kept getting the same value. The tests we use aren’t particularly accurate, so .3 may be a little closer to 0 than it suggests. Without calibrating it’s tough to tell.

FWIW, I’m currently dosing 5.7ppm per week in a tank I’m trying to figure out. I did a couple weeks front loading 13ppm with each of two 80% water changes per week and didn’t see any ill affects. I’m thinking you’re probably pretty close since you’re seeing the base level starting to rise at the end of the week. This is the same thing I’m working through now - establishing and keeping that base level while adjusting the other inputs.