Correct, a mini split doesn't exchange interior air with exterior air. The interior air passes across the fins in the head unit and pushes it back into the room.
What do you believe that filtering your sealed room air thru a carbon filter is going to do to benefit your plants?
Again, I understand your sentiments. But a co2 level of 1200ppm isn't a natural environment and in a natural environment (outdoors) cannabis plants daily have light intensity and co2 level swings.
And I feel that there are other aspects of the requirements for photosynthesis that you might want...
While I understand that sentiment, I think you might want to actually determine if co2 is your limiting factor.
But hey, at this point you've got the expensive parts (controller and powered co2 regulator) out of the way.
On your APC8200 set your "Set Center" to 900ppm and your "Set Zone" to 200ppm. That should turn your output control on at 800ppm and off at 1000ppm.
"Output power is on when the CO2 concentration is below Set Center+(1/2) Set zone, and off when CO2 concentration is over Set Center-(1/2) Set...
Just an update. I was able to get the 1000w shipped from a US warehouse direct from the manufacturer on Alibaba for $345 plus tax.
It arrived 5 days after ordering (2/17-2/22) and even had the same Amazon product label as the one from Amazon.
I’ll add another vote for Blue Lab Guardian. Keep a look out on Amazon Warehouse (used), I grabbed my Connect for right at $200 and have had zero issues.