My PH jumps from 79.8 in the morning to 8.4 just before lights out but for most of the photoperiod it sits around 8.3

Mine drops to 8.1 overnight and then climbs to 8.4 during the day. I have checked my calibration numerous times and maintain a steady temperature.

I have read that having a fuge with lighting on in reverse of the display tank can stabilize the pH. On the other hand, my SPS, LPS and fish are very happy and healthy. I've come to ingore pH and concentrate on alkalinity.

The only thing worse than having a pH meter is having 2 pH meters. They will never agree and can drive you batty.

Oh god, I can't even imagine!!

Well I have been trying to justify spending the cash on a ghl dosing pump....I thought if the swing I am getting was out of the normal range I could use the dosing pump to slow drip in Randy's 2 recipe for dkh ( I have been dosing recipe 1 through a fast drip a la Snappy) which in theory should keep my ph more stable. I also run my fuge lights on a reverse cycle...not sure that has any impact at all.

Here you go. It is an interesting recent article by Dana Riddle who is an expert in these sorts of things. Scroll down to the PH in an aquarium part.
http://www.advancedaquarist.com/2009/6/aafeature#h7
Wayne

[quote]
Now that I have a GHL I notice the daily swings, never bothered measuring the swing before but now it's displayed on the controller.:lol:
That said I should have gotten one a long time ago, I like it.:mrgreen:

[quote=Snappy;431553] aw man...what did you have to go and say that for?:mrgreen:

Thanks Wayne...that was a great link!.....except it made me think my PH is a titch low now:lol: