Low alk on new tank
- Thread starter Mr31415
- Start date
That's definitely not good for PH but according to this article from RHF, CO2 is meaningless to alkalinity:
"the total alkalinity of a sample CANNOT be changed by adding or subtracting CO2. Unfortunately, there is an article available on line, which claims otherwise, and encourages people to “lower alkalinity” by adding CO2 in the form of seltzer water. This is simply incorrect."
Chemistry and the Aquarium: What is Alkalinity?
According to the article acid can reduce alkalinity, but that apparently doesn't work with carbonic acid. I don't really know, I'm just the messenger.
"for every proton that leaves the carbonic acid and reduces alkalinity, a new bicarbonate or carbonate ion is formed that adds to alkalinity, and the net change in total alkalinity is exactly zero. The pH will change, and the speciation of the things contributing to alkalinity will change, but not the total alkalinity."
Way over my head and I had 4 semesters of Chem in high school and 2 in college. But, that was a long time ago.
Mr31415
Active member
From where? Outside? House is sealed…
Yes, to the outside. Something I have been procrastinating doing
That is the belief of some. The article I posted says the opposite. I'm personally on the fence.
Either way it would be beneficial to your tank to get the CO2 down. If you can add an airline to your skimmer intake that reaches outside somehow that would be the most cost effective (I do this but it's a basement tank and I simply drilled a hole for the hose to reach outside air). Another option is a CO2 scrubber attached to your skimmer intake. This I suspect would deplete very fast with your measured CO2 levels and long term would be expensive. Another less expensive option is dosing Kalkwasser on a regular schedule to maintain a more or less target PH. @griss does this. Of course combinations of the above are also fine.
All of these methods are for low PH mitigation but if the belief is this affects alkalinity then they should also benefit it. Of these methods, kalkwasser does add alkalinity FWIW.
Mr31415
Active member
After a small test I just completed I am inclined to believe the article. I mixed 20gal Red Sea salt to 35 PSU. Measured 8.2 dKH. I kept the mixing pump on for 24 hours and day later I measured 8.2. I then increased the surface agitation drastically for another day. Alk is at 8.2dKH. Same house… same CO2
