Problem with sodium hydroxide is the increase of sodium having to be delt with in large consumption systems. Calcium reactors and kalkwasser have the benefit of not raising salinity but Calcium reactors have the ph suppression and additional cost of being large enough to keep up. Kalk having evaporation level ceiling. The miniscule amount he doses of the potassium hydroxide may not increase the potassium level above what his system consumes. I know in the latest video I saw he was in on melves reef channel, he said he does weekly icp test. If potassium overdose was a problem I'd assume he would see it occurring via icp test?
I really need to respond strongly here. No offense intended to you, but IMO is is a serious mistake to dose potassium hydroxide to boost pH long term, and I do not want anyone going away from this thread without at least hearing me say that, even if they still want to try it. It is a seriously flawed method that risks rapidly escalating potassium, and there are far better methods that do not risk that concern..
I really do not understand how potassium ever got fingered for this use, unless the "inventor" was just unaware of better options (sodium hydroxide).
Yes, calcium hydroxide is almost balanced and is a good choice that I used for 20 years.
Sodium hydroxide used with a DIY Balling type two part is also balanced and is also a very good choice. Way, way better than potassium. Even without the Balling part C, it is better than potassium.
Potassium hydroxide at levels sufficient to significantly move the pH needle IS NOT EVER appropriate long term, and there's no way to make it OK (IMO). I do not believe coral uptake can match the amount needed. And if you dose much less, you get a pH effect too small to be useful.
Why do you suppose NO commercial reef alk supplements are potassium bicarbonate or potassium carbonate? Same exact problem that everyone already understands. But somehow if we go to hydroxide as the alk additive, potassium becomes OK? Not.
let's look:
Let's suppose we add 1 dKH per day for a year. That's 0.36 meq/L per day or 130 milliequivalents per L per year.
If we add that as NaOH or KOH, then we must be adding 130 meq/L per year
How much Na+ (mw = 23 mg/milliequivalent) and K+ (mw = 39 mg/milliequivalent) is that?
130 meq/L is
Na+ ---> 23 x 130 = 2,990 mg/L
K+ ---> 39 x 130 = 5,070 mg/L
So potassium has risen from 400 mg/l to 5,470 mg/L
a 1,468% increase.
Sodium has risen from 10,800 to 13,790 mg/L
a 26% increase
Thus, the rise in potassium is HUGE and the rise in sodium is not. Of course, both are impacted and reduced similarly by salinity corrections and water changes, but the overall effect is that the potassium rise can still be very large (because more mass is added and the starting concentration is far lower) and the sodium rise is not.
