See the issue with your last paragraph is that you are looking at it as a method for the full alk dosing which it has not been suggested to be used as. It is being used by Chris as a partner to kalk and calcium reactor. Therefore it is 1 part of a multi part system. You keep speaking as if it's a 1 or the other. If anything he is using it to offset the ph suppression of the calcium reactor, and kalk increases the ph even higher or vs versa. Let's say he runs a ph of 8.25 with the calcium reactor and kalkwasser. And the little bit of potassium hydroxide he's dosing pushes it up to 8.32. At that ph he experienced brighter colors and increased growth vs without it. In his farm both would be highly beneficial right.
No, I’m not saying it is all or nothing and made that perfectly clear.
This is a bad idea for most ordinary reef tanks. No amount of “ let’s just see what peoples experiences are” can fix a bad idea. It would have been a disaster in my tank.
One last time. To get a pH boost as you claim, of pH 8.25 to 8.32, even for a brief instant, requires about 0.15 dKH (0.053 meq/L) of alk added via hydroxide (I have measured and published the pH effect of hydroxide). If you want that effect to last for hours or all day, it takes far more.
But even if we assume he only wants that pH effect for the shortest possible time by instantaneous dosing once a day, that will add 0.053 milliequivalents of potassium per L or 2.1 ppm of potassium each day.
In year, that pushes potassium up from 400 ppm to 1155 ppm, assuming no water changes or consumption.
That neither sounds appropriate nor desirable. Might it be exactly what some sort of extreme high potassium demand aquarium happens to need in potassium? Maybe by some freak coincidence it is. Perhaps in a coral farm where no foods are given, just inorganic supplements, it is needed. In a normal reef tank, potassium demand is usually lower.
But there is NO rationale to make any sort of hypotheses that the corals will respond differently than if that same pH and potassium level (whatever the goal number is) is attained with ordinary alk additives and, if needed, potassium supplements.
Both sodium hydroxide and potassium chloride are available as inexpensive food grade additives from
Amazon.
There’s no need to invoke the complications of dosing potassium hydroxide and tying the two together in a way that makes controlling both more challenging.
To all readers, I’ll say this:
Boost pH? Sure, give it a try.
Maintain potassium at natural levels or boost it to higher levels as some have experimented with? sure, give that a try,
But do not expect to substantially boost pH and not get elevated potassium in most reef tanks if you use potassium hydroxide.
And most importantly, DO NOT expect that dosing potassium hydroxide will give any coral effects that are different than are obtained through any other means of attaining the same pH and potassium levels.
My aquarium maintained natural potassium levels with no potassium dosing, and maintained higher pH (8.35 to 8.5) using only calcium hydroxide. Of course some tanks need more alk and calcium, and one needs to decide how to supplement it. There are many suitable choices.
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