PM RFCa4 reactor
 

does these calcium reactor comes with any ph probe ? trying to decide on a ca reactor, vertex rx6, pm rfca4 or go with a geo 618? need to be at least rated for 225g

Only the larger model PM Ca Reactor comes with a pH probe holder (unless the newer ones are different, I've owned older models of both) but if you have the tools it only costs about $5 to add one yourself.

Just have a look at this DIY article.
http://www.reefkeeping.com/issues/2009-03/diy/index.php

It did not say in PM webpage that RFCa6 comes with probe holder

The 4 doesnt come with a holder for sure

Take another look http://www.precisionmarine.com/html/rfca6_2.html there is one pictured in the lid of the reactor.

can u only fill half the reactor chamber with 8lb media instead of 15lbs in the rfca6 with half the chamber empty if the tank its not high demand? will that also effect the ph?

I've been using a reactor for 3 years and I honestly dont know how to answer that. I guess its because I'm a carpenter and not a chemist.

However here is an article that might help you answer it yourself.
http://www.reefkeeping.com/issues/20...ture/index.php