Rising Ph

[Mark Thompson]

Tapwater generally contains Carbon Dioxide which is why you usually see all the small bubbles clinging to the side of your tank after adding it.

As the Acidic CO2 gas is released from the water then this has the knock on effect of raising the PH of the water (making it more Alkaline).

For this reason I believe that tap water will measure a lower PH when it comes from the tap than after it has been standing for a while.

I have used PH Down on my tapwater to reduce it but with no fish in the tank. I think if you have fish in the tank you have to be very very gradual when adding PH balancers as the sudden change can kill your fish.

I believe that the difference from one PH value to another (ie PH7 - PH8) is a 10-fold increase in alkalinity so if for example you are bringing your PH from 8.8 to say 6.8 then you are effectively increasing the acidity by 20 times.

Correct me if anything I say is wrong here I am regurgitating information I have read from books.

 

[Egmel]

I believe that the difference from one PH value to another (ie PH7 - PH8) is a 10-fold increase in alkalinity so if for example you are bringing your PH from 8.8 to say 6.8 then you are effectively increasing the acidity by 20 times.

Almost right, but 6.8 to 8.8 is 100 times different, the scale is effectively logarithmic from what I understand. So if 6 is 10 times more acidic than 7 and 8 is 10 times more alkali than 7 then 8 is 100 times more alkali than 6!

It looks like I need to do a water change this evening anyway, my Bf decided that each of our 1" plecs needed 1/2 an algae wafer, so now the bottom of our tank is strewn with uneaten, disintegrated algae wafer I'm filtering a bucket of water as I type (and cooking dinner, what a multi tasker!) I'll test the pH and use that for the water change if it looks ok