That's odd. Did you have the same issue/ever try running the scrubber without recirculating? I've had a CO2 scrubber on my tank since last August, and just started recirculating it in February to make the soda lime last longer. Haven't noticed any issues.
you can overdose and it will cause that also if you don't have enough mag it can also cause it, just mentioning in case you have investigated those ideas yet.
I did a bit of googling and turns out high PH, high temps and differences in Calc and Mag can cause calcium carbonate to precipitate out of the water. Seems the recirculator worked too well (plus maybe some other factors)
First, you need some CO2. Yes you will have problems if you strip essentially all of it out. Second, you shouldn’t be chasing numbers! (Should be #1) I have my sps tank in the basement and just by pulling skimmer air from outside I can maintain a ph of 8.3 to a low of 8.2 at night. My tank is over 8 years old. All I do is regular water changes and pull air from outside. Before pulling air from outside my ph was 7.9 - 7.8
Then the only other 2 culprits I can think of is the form of calcium additive or moisture recycling thru your scrubber. It's best to use a container as a moisturizer separator on recirculating setups that way it doesn't carry a concentrated solution back into the tank. Also check your pipes and pump, I believe Chris Meckley had a similar situation years ago with a specific calcium additive. But it's probably been 10+ years since I remember hearing about it.
Don't worry about it. Ya don't need it until you're growing wall to wall SPS. Juice is NOT worth the squeeze. Coming from a 8 year old experienced SPS keeper.
