+/- 1/4 of the chamber should be a good start. How often do you want to refill it and how safe is it plumbed into your system is the rest of the question.
From experience, the first time you do a water change and forget to shut off the ATO you will wish you had less in there than more. If refilling it isnt a big deal, I'd say go less.
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.