Lost my return pump for 12 hours now PH is low?

[Saltine]

Return pump died Saturday night around 10PM. I went ahead and through a power head in my sump to keep the water moving, a bubbler in my fuge (in the sump), and a heater in the display. I bumped my gyre from it's typical 50% overnight to 70% to increase surface agitation/oxygenation.

Ordered a pump from Amazon at 11pm, and it was at my doorstep at 11am. My apex was setting off low PH alarms (7.5) but I thought it could be the water just not moving enough down in the sump and I checked the probe it appeared to not be as submerged as usual but the tip was under the water.

I also use kalk in my ATO (which dumped about 1g of water in) the rest I just topped off with fresh. I also use CO2 absorbent through my skimmer, so I swapped that out this morning.

I'll post a pic of my PH graph from APEX, it's still low ever since the pump died. Alk is in my normal range of 9.0.

I run a mixed reef with several SPS pieces/mini colonies so I'm concerned they are going to get upset if my PH was really 7.5, but I can't believe it would really drop that match just for 12 hours with no return pump? I've had my skimmer off that long before and it's never dropped that much.

Thoughts? Anything I should do?

Salt

 

[Saltine]

 

[Ashish Patel]

Your tank PH dropped because lack of oxygen and your refugium going on idle for so long. Install the new pump and let the water stabilize naturally.