Two Part or Reactors?

[True Blue]

I am trying to figure out where the thin line is between dosing two part and buying a Calcium and/or Kalk reactor.
What do you think the maximum water volume should be to dose two part?
Am I right to assume that putting a reactor on a >40 gal. tank would do more harm than good by rapidly raising your PH and by asking for a overdose?
Thanks in advance for the help...

 

[blennymower]

Not an expert here but, it depends on the demand. I have a 75 gallon with a couple of sps frags and others. So im only dosing every three days or more, so in my case not even dosing kalk with the ATO would work. If you have high demand ATO kalk and a reactor would be good.