Dosing Pump failed, now what?

[JP SPS]

I set up a Bubble Magnus Dosing Pump about 5 weeks ago. Last weekend I tested my ca/alk and the Ca was at 512 and the Alk was down at 6.2. I tested the pump and found out that only 2 of the 3 pumps have been working. The Ca and Mg pumps were dosing fine, and the alk pump didn't work at all.

I have 3 corals that look bad. 2 branching montiporas that seem to be receeding from the base and 1 monti cap that has a dead spot and some browning on it.

What is the best way to remedy this? A large water change? Slowly doing alk to bring the number back up?

 

[bobkill]

It will be hard to raise alk with the calc that high, but I would bring the alk up slowly to at least 7.5 depending on type of tank. Water change would be fine but I would nt do a large one, don't jump ur alk from where it is to 8 or something like that . Alk swings CAN kill sps. I would just dose alk and not the other till you are back in line