Calcium reactor ph problem

[Millimylilly]

My calcium reactor ph spikes every day even though the solenoid is set for 7.18-7.2. What might cause the reactor to rise in ph? The recirculating pump and feed pump are always on

 

[ReeferBud]

That is way too narrow a range to be controlling to.

I would set it to a range of 0.2 between the upper and lower set points, not 0.02.

Also, your pH seems too high. What kind of media are you using? The most typical range seems to be around 6.6 - 6.8