Here's my generic advice for such scenarios:
1. Stop all efforts to boost pH.
2. Stop dosing alk for a bit and let it decline.
3. Reduce pH by switching to a low pH alk mix like sodium bicarbonate, or a calcium organic such as Tropic Marin All for Reef.
4. Ensure magnesium is normal to high.
5. Keep organics and phosphate on the high side.
After a few days of not dosing alk, restart slowly, adding additives to a very high flow area so it mixes in fast.
Sorry to bring up an old thread, but I just found this.
My sandbed is like a rock, and has been for around six months. Back in April or May, my Dosetronic decided it would be a good idea to nuke my tank with Alk and Mg. It was something like 1.7L of Alk in one day and 700mL of Mg. I don't use the DT anymore.
Lately I've been having a great deal of trouble keeping my Alk up. It seems the more I add, the lower it goes. My kalk reactor has also been running non-stop for days while my pH is in the 7.8 range.
Based on what I'm reading here, it sounds like I've been experiencing precipitation for months and just didn't know it.
If I understand correctly, the solution will be to turn off the kalk and alk dosing. My Mg is still quite high. I should also turn off the CO2 Scrubber, and to increase phosphates, turn off the algae scrubber.
If I do this, the phosphates will bind to the rocks and substrate, forming a barrier so that it can't absorb anymore pH or alk. Is that right?
Should I dose a bit of NeoPhos to help it along.
