high PH readings in reef tank

[Webo]

I've had a reef tank for over two years now and it has been going great. I recently noticed over the past two days that my PH reading has been creeping higher. I've generally had readings between 8.2 and 8.3 pretty consistently over the life of the tank. The past two days I've noticed PH readings of 8.35 to over 8.4. I was wondering if anyone knew the reason for this. My Alk readings have been about 12 and the Calcium has been around 430 to 440 consistently. Also, my nitrates have been between 1 to 5. I also do weekly water changes.

I thought if the Alkalinity was high, then PH generally went down. Any thoughts?

thanks.

 

[reefman]

i found high alk can lead to low ca. but if your ca is 440,then its fine. ph 8.4 is fine also. if everything is doing good, i would not worry.

good ca/alk/ph relations read up

 

[James983]

If your using a PH monitor either recalibrate the probe or check PH with test kit to be certain the PH monitor is correct. I had the same problem and the PH monitor's probe was shot.