Does all of your top off come through the kalk reactor?
Interesting that you you attribute 0.1 increase in pH to kalk. I guess I would have expected more. This is really valuable information.
It seems like oversizing the skimmer really has helped with CO2 exchange.
Would you mind pulling data from your controller logs to get a % time skimmer on with CO2, % time skimmer on with room air, % time skimmer off?
I know you mentioned earlier in the thread that you're less interested in the skimmer for filtration and more interested in it for pH control. I think this is the right idea. I have run many tanks (even large tanks!) with no skimmer. That being said, do you still get some skimmate production with this setup?
Thanks for taking the time to post this thread. It's incredibly useful. I feel like many CO2 scrubber threads are from people who have seen only marginal increases in pH and have not been successful in setting up in a way that manages both pH and moderates scrubber media consumption.
I'll try to pull the skimmer scrubbing info. However, my estimate is that it's on 4-12hrs a day depending on home CO2 levels. Usually around 8hrs.
You can actually calculate pH impact of kalkwasser drip and you made me want to figure it's actual impact.
Per @Randy Holmes-Farley :
"In my experiments, adding 0.5 meq/L (1.4 dKH) of hydroxide (equivalent to 1.25% of the tank volume of saturated limewater) boosted the pH of new IO salt mix (alk about 11 dKH) by about 0.66 pH"
I'm adding about .8dKH and .8% by volume. So I'm guessing I should be getting about .42 increase in pH per day or 0.017 per hour. Anecdotally, I believe my average pH is about a 0.1 higher. Looking back at some old notes just dosing Kalkwasser appears it may have a slightly higher boost to the tank like 0.12.
I guess I could turn off my skimmer for a couple of days and see where things settle to. Then similarly stop the Kalkwasser for a couple days and see that as well.
I can say, when my skimmer was off line for a day or so,, my pH dropped to a low of 8.12 from a normal low of 8.24.
So it could be that I'm getting something around 0.12ph boost from both Kalkwasser and CO2 scrubbing skimmer.
My tank prior to pH boosting was usually between 7.9 and 8.0. Adding ~0.24 gets me close to where I am now. The reverse lighting refugium boosts a little as well....so maybe those # are close enough.
I attribute the low boost from others who implement CO2 scrubbers is due to it not adequately out competing the other sources in their tank...i.e. their power heads and such are doing a good job aerating their tank with high CO2 air.