Calcium Reactor advice


I want to purchase a calcium reactor for my tank. I've always had trouble with this tank keeping my calcium levels up and haven't had much purple coraline growth. My last tank which was smaller I had too much growth. This tank is three years old 125 DT, 35 refugium, 35 sump, octo 200 ( with a new pump in case you read my recent thread about the sicce pump suc..!), 3 175 watt halides aand 4 96 watt accents. mag 9.5 return pumps, ATO top off system, and all water is RO/DI. I have used purple up, liquid calcium, part A&B and have a 5 gallon drip doser that I drip kalkwasser. I need recommendations on good brands. I know I'll need ;
CO2 device and solenoid, pump, cacium reactor, bubble counter and should get a PH probe. Everyone with advice please repl !!!!!!