Ph Of My Tap Water Has Dropped By Quite A Lot!

[214jay]

Hello.  My PH of my tapwater has always been consistently 8.2.  A few days ago I changed 50% of the water in my main tank and noticed one shrimp going completely bonkers, swimming at warp speed everywhere! 
 
Today I changed my smaller shrimp tank and thought out of interest I would do a PH test.  The tank was a steady 8.2, I tested the tapwater and it is now between 7.2 and 7.6!!!  Upon checking the main tank sure enough the PH has dropped to around 7.8.
 
Is this normal and does this ever happen?  I thought the PH would remain stable out of the tap, I am feeling fortunate nothing has gone into PH shock.
 
I have no problem with a lower PH as it will be better for my fish and shrimp but should I now slowly do small 5-10% PWC everyday to bring the PH down and let the fish adapt rather than the weekly 40-50% WC?
 
Thanks for any advice!

 

[fm1978]

Are you dosing CO2 in that tank?

 

[DevotedToDiscus]

At which point did you check it? If you check it just after you take it from you tap it will contain dissolved Co2, which will give it a lower reading. After some hours these gases will be released an the pH will rise. It can typically be a difference of 1 degree. To test this, take a glass of your tap water, test a sample, and then leave that glass for 24 hours and test it again. This way you can note the difference and get a true reading.
 
I there is a significant difference in the readings, then the safe answer is to simply age your water before changing it. You can speed up the process of driving the gasses out if you run an air pump and air stone in the aging water to agitate it, and get the gasses out quicker.
 
Hope that makes sense. 

 

[214jay]

Nope, it does have live plants but no CO2. 
 
All tanks and tapwater have always remained 8.2.

 
At which point did you check it? If you check it just after you take it from you tap it will contain dissolved Co2, which will give it a lower reading. After some hours these gases will be released an the pH will rise. It can typically be a difference of 1 degree. To test this, take a glass of your tap water, test a sample, and then leave that glass for 24 hours and test it again. This way you can note the difference and get a true reading.

 
This drop in PH from the tapwater only seems to have happened over the last week, prior it was a steady 8.2 and was the same in both tanks - I test for PH fairly regularly.  I have just tested some drinking water that has been left out a couple of days, reading the same 7.2 to 7.6. 

 

[fm1978]

It must be what DTD suggests then.
 
Either let your water sit for a while before adding as suggests by DTD, or just just add much more slowly next time.

 

[214jay]

 
It must be what DTD suggests then.
 
Either let your water sit for a while before adding as suggests by DTD, or just just add much more slowly next time.

 
As mentioned above, the tapwater, regardless of leaving out for 24 hours or straight out of the tap is now 7.2 to 7.6.  Prior to this it has always been 8.2, regardless of leaving for 24 hours or more.  Both tanks have always remained the same as the tapwater at 8.2 prior to around a week ago. I test all parameters of tapwater and tanks quite a lot (excessive compulsive side no doubt) so I know there is something quite different.
 
Is this normal for such a big change from my water supply?

 

[Sophie]

Ring your water company and find out 

 

[214jay]

 
Ring your water company and find out 

That would probably cost me more than my tank on their 0845 number! 
 
I have just rang my LFS (under 5 mins away from me) and they have notice a drop too....guess it just happens, not complaining though as I want a lower PH!!

 

[DevotedToDiscus]

Nope, it does have live plants but no CO2. 
 
All tanks and tapwater have always remained 8.2.

 
At which point did you check it? If you check it just after you take it from you tap it will contain dissolved Co2, which will give it a lower reading. After some hours these gases will be released an the pH will rise. It can typically be a difference of 1 degree. To test this, take a glass of your tap water, test a sample, and then leave that glass for 24 hours and test it again. This way you can note the difference and get a true reading.

 
This drop in PH from the tapwater only seems to have happened over the last week, prior it was a steady 8.2 and was the same in both tanks - I test for PH fairly regularly.  I have just tested some drinking water that has been left out a couple of days, reading the same 7.2 to 7.6. 

Sounds like the supply has changed then. The Tetras in you signature are actually going to prefer the lower pH to be honest, but naturally you need to be wary of pH potential pH shock during water changes. I would suggest smaller more frequent changes, as this will cause hardly any pH shift in your tanks, should your tap water fluctuate. 

 

[214jay]

Yes agreed, with having tetras its definitely a positive!  Shame I have to do such big water changes but water quality is rubbish here and nitrates are high out of the tap will stick to more lower % water changes and go from there.

 

[fm1978]

Very strange to have changed the supply, eh?
 
If it's good for your tank inhabitants then that's a bonus though!

 

[214jay]

It is rather odd, shame they couldn't remove some of the nitrates whilst they were there!

 

[EllieJellyEllie]

The "normal" people we know nothing of would call us weird for testing a glass of water for pH levels......

 

[Sophie]

The "normal" people we know nothing of would call us weird for testing a glass of water for pH levels......

 
I remember advising a customer at work to ring the water board and ask them about the water stats and they told me they were too embarrassed.
I've rung them to find out my stats and asked them how often they get calls from people about the water in regards to their fish tanks and they said weekly and more so it's definitely not unfamiliar to them

 

[214jay]

 
The "normal" people we know nothing of would call us weird for testing a glass of water for pH levels......

Ha ha, just another day for us!

 
I remember advising a customer at work to ring the water board and ask them about the water stats and they told me they were too embarrassed.
I've rung them to find out my stats and asked them how often they get calls from people about the water in regards to their fish tanks and they said weekly and more so it's definitely not unfamiliar to them

 

Its good advice, I have contacted the water board by other means and they are calling me back to discuss water quality!