How is ph only 7.3?

[JMurphy97]

I recently re-calibrated my ph probe. I left the probe into the solution for around 10 minutes each time to allow it to stabilize and make sure it wasn't going to keep swinging.

Today I look at the reef keeper and it's telling me that the ph is 7.3! Way too low. I never really had over 7.8 but it's never been this low. So I get the test kits out and find out how everything else is.

sg- 1.026
temp 78
cal was 405- I adjusted it to 430
mag 1,410
alk 9.6 dkh
ph 7.3

Recently I adjusted the mag from the 1,300-1,350 range to past 1,400 to fight some brown slime. Before doing this the alk was higher around 12 dkh. Since mag went up both the alk and ph came down.

I do have kalk in the topoff water and it evaporates pretty decently.

Water volume is about 50 gallons. I have a small amout of chaeto in the sump on a reverse light cycle from the main light. What should I do?

 

[FullBoreReefer]

I recently re-calibrated my ph probe. I left the probe into the solution for around 10 minutes each time to allow it to stabilize and make sure it wasn't going to keep swinging.

Today I look at the reef keeper and it's telling me that the ph is 7.3! Way too low. I never really had over 7.8 but it's never been this low. So I get the test kits out and find out how everything else is.

sg- 1.026
temp 78
cal was 405- I adjusted it to 430
mag 1,410
alk 9.6 dkh
ph 7.3

Recently I adjusted the mag from the 1,300-1,350 range to past 1,400 to fight some brown slime. Before doing this the alk was higher around 12 dkh. Since mag went up both the alk and ph came down.

I do have kalk in the topoff water and it evaporates pretty decently.

Water volume is about 50 gallons. I have a small amout of chaeto in the sump on a reverse light cycle from the main light. What should I do?

Maybe get some crushed coral substrate and place it in a filter sock/media bag and toss it in your sump.

Years ago, granted it was freshwater, but i used crushed coral to raise the ph without adding chemicals.

Hopefully this will work for you also...

 

[blanden.adam]

It's really not likely your pH is that low. The calcium carbonate on your rock would be dissolving and raising the pH back to 7.8. There's almost certainly a problem with the measurement.

 

[Recliner]

I'm assuming you used a test kit to confirm the 7.3 reading the probe was giving you. If it's from both the recently calibrated probe AND a test kit, I would assume that the 7.3 is accurate.

 

[downbeach]

How old is your probe? I'd try to recalibrate, if it's still giving that reading I'd be very suspicious of the probe.

 

[JMurphy97]

No other test kit. The probe is pushing two years give or take. Tomorrow I guess I'll take a sample to the lfs and have them test it. They use api kits I believe.

 

[blanden.adam]

yeah, 2 years is rather old for the cheap single junction electrodes we tend to abuse in our tanks.

 

[disc1]

No other test kit. The probe is pushing two years give or take. Tomorrow I guess I'll take a sample to the lfs and have them test it. They use api kits I believe.

That's an old probe. Either way, no matter what any test says, if you don't see rock and sand starting to dissolve then you can rest assured that pH measurement is not right.

 

[JMurphy97]

Well then a new ph probe will be on the things to do tomorrow. Lucky for me the lfs carries brs products. It is almost like going to brs to pick up supplies. Thanks guys I didn't think that was old for a probe. How about a temp probe. Should I look into a new one also?

 

[blanden.adam]

Not unless you are seeing problems.

 

[bertoni]

I wouldn't spring for a temperature probe, either, but I did get a decent glass thermometer from Cole-Parmer.

 

[disc1]

but I did get a decent glass thermometer from Cole-Parmer.

+1 A good general rule in any type of science is when you get a measurement that sounds unreasonable or odd, question the measurement first. More often than not you'll find the answer there.

You can calibrate those thermometers pretty easy. If you make a glass of crushed ice and water and let it sit for a few minutes, you'll get a good reliable 32F / 0C. If the thermometer goes high enough, a pot of boiling water will be 212F / 100C depending on where you live. Those in Denver and other "high" places might have to adjust for altitude.