PH Potassium hydroxide and TLF PH Balance Q

[Laurens]

I just watched the video's from ACI. I dont remember the exact quotes but the guy form ACI tells after raising his ph trough koh he had to add far less kh (calcium reactor) while having 30% + growth. He thinks the carbonic acid does things to the kh/carbonates (I think he also thought this happened to other ions like ca) that makes it react/participate so the kh drops. He also said caoh and koh doesnt add kh, part of his proof is his ca and kh are still balanced while adding koh. So he is wrong?

Adding hydroxide tends to raise pH, and that rise can increase both abiotic precipitation of calcium carbonate and coral calcification. Usually, one would not expect alk to actually decline, but it can. The drop may also be test error. The Hanna has a specification of +/- 0.4 dKH at 8 dKH.

 

[Randy Holmes-Farley Verified Community Expert]

I just watched the video's from ACI. I dont remember the exact quotes but the guy form ACI tells after raising his ph trough koh he had to add far less kh (calcium reactor) while having 30% + growth. He thinks the carbonic acid does things to the kh/carbonates (I think he also thought this happened to other ions like ca) that makes it react/participate so the kh drops. He also said caoh and koh doesnt add kh, part of his proof is his ca and kh are still balanced while adding koh. So he is wrong?

Of course he is wrong about hydroxide not adding alkalinity. Plenty of folks use that as the ONLY way to supplement alkalinity, including in my tank for 20 years. lol

The growth does not surprise me, and the reduced need for alk should not have surprised anyone since the KOH is adding alk. That addition obviously reduces the need for other alk supplements.

It takes longer to see calcium declines than it does to see alk declines when underdosing, and since many salt mixes have excess calcium, normal water changes might add as much calcium as is needed to balance the alk added.