auto water change

I working on an auto water change system. My track record of doing water changes about every 1-3yrs and dosing haphazardly every 3-6mo for no particular reason is coming to a close. I simply have too many hard corals and I'd like to keep them growing. If you hate dosing and water changes do a...

I'm contemplating an auto water change mainly because I don't want to measure 2-part and my RO/DI is already geared for it with my barrel tender. I'm curious what people are using for this and how long it's been running and/or how hard it is on pumps, etc. Keep in mind I have a 300gal so the...