Suddey PH dropped for unknown reason

[Tou]

Hi Reefers
I need some help, my tank is 2 year old and been very stable. But for some reason my PH dropped very suddenly from 8.2-7.6 within few hours last night. I manual dose alkalinity right away and it went back up to 8.2 within 2 hours. Then this afternoon a sudden dropped again, back to 7.6 again.
I also do a API PH test and it seems to be at 7.6
Can anyone tell me what's going on? I did add anything new for the last month or so. It was very stable at 8.2ish.
Thank you all, all comments are appreciated.

 

[Pistondog]

Opening and closing any windows?

 

[chadfish]

Bad sensor?

 

[Tou]

I thought it was bad sensor but also checked with API PH test, confirm is that low.
Window is always opened and have a tube from skimmer air vent to outside window

 

[Pistondog]

Bad sensor?

Op confirmed 7.6 with a 2nd test method

 

[Pistondog]

Carbon dose vinegar?

 

[((FORDTECH))]

Hi Reefers
I need some help, my tank is 2 year old and been very stable. But for some reason my PH dropped very suddenly from 8.2-7.6 within few hours last night. I manual dose alkalinity right away and it went back up to 8.2 within 2 hours. Then this afternoon a sudden dropped again, back to 7.6 again.
I also do a API PH test and it seems to be at 7.6
Can anyone tell me what's going on? I did add anything new for the last month or so. It was very stable at 8.2ish.
Thank you all, all comments are appreciated.

I notice same drop the day before. Question is what are you doing at this time? Did you feed a large amount ?

 

[Tou]

.

 

[Tou]

I been using bio pellet for over half an year and never had any problems.
I didn't know feeding can lead to low PH. But my feeding is the same as my normal routine.

 

[((FORDTECH))]

I been using bio pellet for over half an year and never had any problems.
I didn't know feeding can lead to low PH. But my feeding is the same as my normal routine.

Show me a picture of same graph except for all and not 1 day please

 

[((FORDTECH))]

My ph drops hard every day when my doser goes off and doses ab+

 

[Tou]

I did feed AB+ today but not yesterday.

 

[((FORDTECH))]

I did feed AB+ today but not yesterday.

I was looking to see how many times thru week it happened. Looks like only the 2x. Did you dose the ab+ about 5 pm ?

 

[Tou]

I dose ab+ around 2pm today

 

[((FORDTECH))]

I dose ab+ around 2pm today

Hmm very strange then I’m not sure what else to check

 

[Randy Holmes-Farley]

Those two downward then upward spikes look like electrical or other interference to me. They do not look like real pH changes.

I would not do anything about it except keep monitoring.

 

[Suohhen]

What Randy said. The API tests are not very accurate so that is well within the error bands. Make sure the probe is clean, staying submerged in water (top off issues or one off events like feeding or water changes can vary sump water levels), and not in a stagnant area.

 

[Tou]

Ok cool, thanks guys I will try to clean it and see what happens.