almost giving up on the hobby

[Amadod2]

I have a 75g the rowaphos is changed monthly and I use about two full table spoons. I been only checking phosphates as that's the problem I been having. The tap water test for phosphates with the Hanna checker was .25ppm. What I'm trying to do is get my top off water and water change water to 0ppm. Because as of now I'm just adding phosphates into the tank