Another low ph question

[USMA36]

Longish story. I just upgraded from a 90 that was met in my living room. My house is a newer home this sealed up pretty tight. I ran a co2 scrubber on the tank to keep ph between 8 and 8.3. Now the new tank is a 220 gallon. It’s located in my basement. I use a lifereef skimmer with a Maxspect jump 10k pump which advertises 3100gph. I have also hooked up the Co2 scrubber to the skimmer. Even with the pump running 100% I can’t get pH above 7.88. Range 7.69 -7.88. I would think the scrubber would just exhaust the media but it’s not or atleast not changing color. I have changed it out with media from a new sealed bag just in case I had a bad batch but there was jo change. The co2 scrubber is drawing in humid air from the skimmer cup as well. Is the skimmer too small? I can’t see that being the issue. Pump too small? Again 3000gph should be plenty. Tank location in basement and co2. Sing heavier than air collecting down there? How can I raise pH. Open windows arent an option especially in winter. Flow is 3 MP40s on reef crest max 80% they are about halfway up the glass on both ends. I use a Vectra L2 on 50% as a return pump. I can’t really crank it any higher as the sump becomes too noisy. My alk is steady around 7.8. Not much coral right now. Will be adding a bunch shortly.

 

[shwareefer]

I assume you are measuring PH digitally. Have you compared against other measuring devices or kits?

 

[USMA36]

Yes. Apex probe brand new and calibrated. Same reading with old probe.

 

[arking_mark]

Your shimmer probably can't compete with the rest of the tank aeration.

I recommend kalkwasser drip and a refugium.

Once the tank matures and has lots of photosynthetic organisms, you'll have a nice bump during the day. Refugium will give you a nice bump at night.

Other options are a house air exchanger.

To get my skimmer to compete with my tank I had to super-size the skimmer ~3x recommend.