At least in Germany there was no consensus that potassium supply is necessary or beneficial at all. I also had doubts that there may be any positiv effect of potassium supply.
Armin Glaser, who has written a book "Ratgeber Meerwasserchemie" (Guidebook Saltwater Chemistry), published the position that a little less is better than a little more since concentrations only slightly over the natural concentration of 400 ppm had negative effects to some test organisms like mysids while low concentrations down to 200 ppm had no negative short term effects.
My own first trials with potassium under the instructions of an advocat of potassium dosage went very bad and killed some corals and affected others very badly.
Only recently, after years without any water change in one system, potassium concentration had dropped to 300 ppm and I decided to increase it to the normal 400 ppm which showed some positive effects.
Since our salts are well supplied with potassium and it is easy to keep it at natural levels with normal regular water changes, I do not expect a positive effect of routine potassium dosing, rather a negative effect. I can only recommend a potassium supply for tanks with proven deficiency. For this we offer the products Tropic Marin Potassium and the K+ Pro test kit.
My tank consumes a fair amount of potassium. I have to dose it along side all for reef. I think my refugium is the largest sink of it. I'd rather have potassium than some of the trace metals which I found to have built up over time in my tank. I have gone through several gallons of all for reef without water changes on my 75 gallon tank, and some of the metals were elevated without any source of rust in the tank. I'd be glad to share my icp test with you if you are interested, especially given most people don't do near 0 water changes tanks and all for reef together as far as I am aware.