PH suddenly at 7.0

[cjrudy]

Normally I check my PH every day or too , but I probably haven't checked it in 4-5 days and all of a sudden it's at 7.0 when its normally its 8.2-8.4I run Kalk on a normal basis in my ato and have made no changes recently. The only real changes in the past 4-5 days is that we have shut our windows but a 1.2-1.4 drop is a lotI have checked with both a test kit and hand held monitor and strangely enough the corals look fine currently have nice PE on my SPS
And Alk is at 9.0

[BigAl07]

I'd suggest opening a window and monitor to see what happens. With tighter and tighter energy codes going into effect around the nation we're making our homes more and more "Air tight" which isn't the most ideal situation in regards to air exchange and "Indoor Air Quality".

Are you currently "Heating" the home as well?

[cjrudy]

Too cold to keep the windows open an we have had the fireplace on and the heat on briefly but I didn't have this problem last fall/winter

[yankieman]

im not sure but that sounds like a huge drop to me and id suspect faulty testing if the corals seem fine especially with the alk at 9
,, jmho

[jjmoneyman]

I'm also surprised your coral aren't upset with the sudden drop in Ph.

[reefer gladness]

I suspect the CO2 released from the fireplace in a non-ventilated environment may be the culprit here, the CO2 will reduce pH.
I'd do a couple 25% waterchanges over a couple days, test your freshly mixed water too.

There's also something I ran across called 'old tank syndrome' that's too lengthy to explain and I didn't fully grasp it either but worth googling maybe. I do suspect the fireplace/heater was the culprit though.

[cjrudy]

Tested again this morning with the PH meter after recalibrating and it still read 7.0Retested with a kit and it showed 8.2. Whew!!!I think what happen last night is in my panic I only added 4 drops instead if 5 with the API kit. Definitely something wrong with my handheld , maybe a bad sensor ?

[BigAl07]

Whew! Good catch.

Could be a bad sensor I'd email the manufacturer and see what they offer for advice.

[cjrudy]

I bought it used from a fellow reefer , probably out if warranty, it's an HM, I'll probably just get a new sensor

[ReachTheSky]

Calcium Carbonate (rocks, sand, coral) would start to melt with a pH that low. Sudden pH swings are more often caused by probe issues than actual tank related ones.

[cjrudy]

I just ordered a replacement probe for $25

[jjmoneyman]

good call!

[yankieman]

I just ordered a replacement probe for $25

Glad you figured it out ,,,,,,,

[steved13]

+1