Village Idiot
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My tap water pH is about 8.2. The water coming out of my new RO/DI unit has a pH of 6.0. Is this normal -- I thought it would be about 7.0? When I add the salt mixture, will the pH come back up to 8.2 or so?
RO/DI pH?
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andsoitgoes
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RO should be 7.0, that's the entire point of it that it stabilizes the water...
what PH test are you usign?
what PH test are you usign?
Actually don't worry about the pH. With ultrapure water the pH changes if you give it a threatening look. It has zip buffering capacity and even exposure to the air changes the pH (usually lowers it). Also, unless you are using laboratory grade pH meters, electrodes and special techniques, it is impossible to measure it accurately. Be assured it will adjust itself when mixed with salt or added to the tank as top off.
Village Idiot
New member
I'm using my FW API test kit. I was doing a water change in my FW tank and thought I'd try out my new RO/DI...pH of 6 didn't look good, so I added 4 drops of my pH up, retested, and the pH went over 8 again. I decided I wasn't putting this in my FW tank and went with good 'ol tap water. Glad to hear the salt will buffer it out.
Egads, even if the RO/DI tested at pH 12 it would be far better than tap! :eek1:
The pure water absorbs carbon dioxide from the air. That lowers the pH. Don't worry or try to adjust it (as you found out). It is fine. Any pH adjustments should be done the next day and only to the tank water if the pH indicates low or high values.
The pure water absorbs carbon dioxide from the air. That lowers the pH. Don't worry or try to adjust it (as you found out). It is fine. Any pH adjustments should be done the next day and only to the tank water if the pH indicates low or high values.
Baking soda, mix a teaspoon per gallon a day ahead of time and the pH should be around 7.9-8.3 when you do the dip the next day.
Baking soda takes some time to equilibrate also you want gas exchange in the RO/DI water so that the final pH is at least 7.9. If the pH is lower after about 4 hours you can add another teaspoonful. the good part about baking soda is that it will not increase pH to over 8.3.
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