Need to raise dKH

[AdeptMrSniffles]

I've been using Tropic Marin Bio Actif salt mix for water changes for the past 2 months, 15% weekly. I test the levels in the bucket when I mix and they come out to: Cal 440, dKH 8, Mag 1440, and pH 8.2 @ 1.026 SG. However, I'll test my water the next day and my dKH is at 5.1!! but the others are right on. I've been adding Brightwells alkalinity increaser every night, about 20-25ml, but it's barely raising it. Any ideas on how to raise it up? I have 1 SPS, a green stylo, that's larger than a softball. Also, my Frogspawn has been splitting heads like crazy. I'm assuming these guys are sucking it up pretty hard core. Should I consider a DIY kalkwasser?

 

[Smitty]

I used to use purple up...not only does it raise calcium to promote coralline algae, but it also raises your alkalinity too, and it's hard to overdose with it.