Question about PH and well water

[HotTunaCartel]

EDIT: little update, contacted usgs and they transferred me to usgs New York Water Science Center.  Waiting for a call back to see if they have an answer to why the ph has changed out of the tap

 

I usually don't test our well water as I know offhand the PH is 7.8 and nitrites/nitrates are 0 out of the tap (well water).  

So I started using the waterboxes video on monitoring PH drop while using co2 to get the optimal range. I'm using a co2 generator with citric acid and baking soda.  

As per the instructions I took a ph reading this morning before the lights came on and saw 6.6 - 6.8, which I figure is ok considering its a blackwater tank.  Just for the hell of it I decided to check the ph out of the tap and saw it was the same reading.  

Over the summer, the last time I checked out of the tap it was 7.8. 

So this is weird now as the ph in the well water is changing drastically.  We did have massive rains this year, just had another 5.5in late last week.  

Could minerals have washed out due to all of the rain.  I believe our aquifer feeds in from the Delaware river and we haven't had flood stages reached for probably the last 10+ years.  

 

Edited November 2, 2021 by HotTunaCartel

[KaitieG]

That's a really good question--I had something similar happen to our well water with nitrates, not PH.  We'd had about 5ppm nitrates and then in the spring it jumped up to 30.  I guess off hand I'd say that yes, well water can change from time to time and ground water issues like rain and snow melt seem to have something to do with that, but that's just been my sample size of one observation 🙂 

[HotTunaCartel]

On 11/2/2021 at 12:16 PM, KaitieG said:

That's a really good question--I had something similar happen to our well water with nitrates, not PH.  We'd had about 5ppm nitrates and then in the spring it jumped up to 30.  I guess off hand I'd say that yes, well water can change from time to time and ground water issues like rain and snow melt seem to have something to do with that, but that's just been my sample size of one observation 🙂 

That is one thing that hasn't changed in our water but yea really weird.  When we moved out here 16 years ago it was like OMG this water is fantastic, no chlorine etc.  I guess this may be the tradeoff lol.   Kinda worried if I should shut off my co2 for the time being as I really don't want to drop the ph below 6 and its currently 6.4 -6.6 

Going to take a few more ph measurements in the tank today and will shut the co2 off it starts to get too low.  

[Mmiller2001]

I wouldn't worry about how or if, but would monitor your source water KH. The reason a pH is a certain value is mostly related to a certain value of KH. 

I would grab a sample of your tank water and set it out for 48 hours and use that measurement as your degassed pH.

Edited November 2, 2021 by Mmiller2001

[KaitieG]

Our water has such high Kh that I'm pretty sure the PH wouldn't change no matter how much rain water got added!  Mmiller's suggestion is a good one!

[HotTunaCartel]

On 11/2/2021 at 12:38 PM, Mmiller2001 said:

I wouldn't worry about how or if, but would monitor your source water KH. The reason a pH is a certain value is mostly related to a certain value of KH. 

I would grab a sample of your tank water and set it out for 48 hours and use that measurement as your degassed pH.

Thanks for the reply.  Will do the sample test.  

I did measure the kh out of the tap, appears to be around 3.5 

[HotTunaCartel]

Update:  Took ph readings every two hours.  I probably got fairly close to 6 at lights out (around 7:30pm) 

I did hear back from USGS, and send them some info on my well.  Waiting to hear back 

 

[gardenman]

As a general rule with wells, deeper wells are more stable than shallow wells. You can often find water as shallow as ten feet or so, but that shallow water tends to be highly variable in quality.

Older wells would often use iron/steel casings (nowadays everything is PVC) and groundwater could/would eat away the casing and then pour into a deeper water well and you'd end up with the same water you'd have gotten with a shallow well. That was a common issue here in South Jersey until the switch was made to PVC casings. A homeowner would pay a lot of money for a deep well (300' or deeper) and tap into great water. After a few years though they'd notice the water would change. An inspection of the then steel casing would show that it had developed leaks and the groundwater was now flooding their deep well. 

If you've got a shallow well, you'll see wild fluctuations in water quality. A neighbor liming or fertilizing their lawn can affect your water pretty dramatically. Heavy rains or snow can affect your water. Shallow wells are prone to wild fluctuations. If you have a deep well and are seeing fluctuations, then it's possible you've got a casing failure that's letting shallow groundwater pour into your deep well.

[HotTunaCartel]

On 11/3/2021 at 9:21 AM, gardenman said:

As a general rule with wells, deeper wells are more stable than shallow wells. You can often find water as shallow as ten feet or so, but that shallow water tends to be highly variable in quality.

Older wells would often use iron/steel casings (nowadays everything is PVC) and groundwater could/would eat away the casing and then pour into a deeper water well and you'd end up with the same water you'd have gotten with a shallow well. That was a common issue here in South Jersey until the switch was made to PVC casings. A homeowner would pay a lot of money for a deep well (300' or deeper) and tap into great water. After a few years though they'd notice the water would change. An inspection of the then steel casing would show that it had developed leaks and the groundwater was now flooding their deep well. 

If you've got a shallow well, you'll see wild fluctuations in water quality. A neighbor liming or fertilizing their lawn can affect your water pretty dramatically. Heavy rains or snow can affect your water. Shallow wells are prone to wild fluctuations. If you have a deep well and are seeing fluctuations, then it's possible you've got a casing failure that's letting shallow groundwater pour into your deep well.

Excellent explanation and thank you so much for taking the time to respond.  

I think our well is 60 feet, meanwhile my brother who lives 30 miles a way has a well over 600ft deep.   I can see how things that neighbors do in the surrounding area could affect the parameters of the ground water.  I do know my one neighbor made a comment a few months ago about supposed cholera in his water and was going to "shock" the well.  I didn't think about it now because it seemed like such a strange thing to say.  

The water science center did get back to me and provided me with his phone number so I'll be calling today.  

[HotTunaCartel]

Update:   

Had a great hour long conversation for the guy from the USGS.  As @gardenman had also explained, there are numerous reasons why the ph can change rapidly in shallow wells.  One of the things he told me as well was that even the intensity of sunlight day to day can change the ph.  The one question he kept going back to due to the amount of rain and flooding that has been happening this year is if rain could have got into the well head.  Our well head is hermetical capped and we live on the side of a mountain so I don't think that would be it.  Another interesting thing he said hes seen is swings of day to day between 6 and 8 ph just due to weather.  

So all in all, I think I just have to be careful and monitor my co2 levels until I get a good understanding of how the ph changes while I do water changes.