After six days straight of water changes to normalize my salinity, these are my parameters. My phosphate just won't stay down. I have chemipure going in my filters. Should I start using phosphate-e? I'm not sure if anyone has any other ideas.

My 75 gallon is tempered glass. Is there a realistic way to add a sump in the cabinet below without drilling?

(Pic of my favorite zoa for tax)

As was recommended, I did a 20% water change yesterday. Finally have all new testing supplies (Hanna nitrate, phosphate, calcium and Salifert ph magnesium and alkalinity). My levels are still off. I can try testing again later, but I feel so defeated. My BTA looks awful and I'm terrified I'm going to lose it.

Any thoughts or suggestions?

Would someone be able to to give me some perameter advice? I am still waiting on my Hanna testers for calcium, nitrate and phosphate. I did use my new Salifert magnesium, PH and alkalinity tests, so I'm fairly sure they're accurate. I used API for nitrate and phosphate (I don't think it's at all accurate).

I have a 75 gallon reef tank with fish, inverts, a BTA, and zoas. I'm trying to get my levels stabilized and within the normal range. I did two large water changes last week that definitely helped, but stressed my tank out. I'm frustrated.