Calcium Reactor Set-Up pH 9.54?
 

Ok, I am not new to a calcium reactor, been running one for years. So I'm more than familiar with it's workings.

So here's the issue... Just finished my upgrade to a 120, and with that I went with a new Vertex RX-C 6D Calcium Reactor. This is filled with Two Little Fishies Reborn Media. Also mixed in is ZeoMag per the describe ratio of 10-30% so I used 20%. The second & third de-gas chambers are 100% Reborn media.
Two new pH probes, one in sump, one in CaRx, both calibrated. Upon starting up the CaRx I noticed the pH in the reactor at 9.54. This was prior to turning on the Co2. I thought that was way to high, and maybe the pH probe was to blame. Tank is running 7.98. So I switched the two probes, but the issue did not follow the probes as the reading was within a few point after the switch. Switch them back, same readings. So I know this rules out a probe issue.
I can lower the pH in the reactor with Co2, but at a ridiculous bubble rate as in a constant stream.
If I turn the Co2 off and let it run, the pH return to the low 9's.

So what could be causing such a high pH inside the reactor, when the tank water that is suppling it is only 7.98? Maybe it needs a break in period? I've added the same media before to my running system, and I never saw a pH spike. There isn't any livestock in the tank, still in the holding tub for another week. And I know I don't need the CaRx yet, but I trying to be sure everything is working properly before I transfer fish and corals. I know the tank pH will raise once I put the skimmer in (it's in the holding tub now).

TIA

Only thing is the media. I would test a small sample in a cup of water to see which one is the culprit.

ZeoMag will increase the pH within your calcium reactor for 2-3 days.

Unfortunately all of the ZeoMag is in the reactor.

That's what I'm hoping. This is the first time using it.

I'll let it run a few days without Co2 to see if it settles in.

Thanks to both of you for the replies.