Actually, denitrifying bacteria do raise pH by increasing alkalinity. In nitrification, for every 1 mg of ammonia oxidized 7-8 mg alkalinity (as CaCO3) is removed from the water. In denitrication the opposite happens but not to the same extent. But I don't think that's the reason J jaws7777 tap pH is lower than his tank pH.J. H. said:He probably has coral or shills or bones some sort of buffer in there. Or maybe the fancy denitrator bacteria raise the ph instead of lowering it.
My water is similar. It exits the tap around 8.6 and settles around 7.45 after aging.Hendre said:I have very soft water so why the high PH I'm not sure ... Mine comes in 9.0 and settles at 7.5, on that note I need an ageing barrel
The pH of water will rise or fall after aging/aerating in a cup, bucket or aging tank for ~24 hours. This is because CO2 levels differ between water underground or in distribution pipes and between water at the surface. Water with excess CO2 will exit the tap at a lower pH and rise to higher pH after ~24 hours aging/aerating for ~24 hours. Water with relative lack of CO2 will exit the tap at a higher pH and fall to a lower pH after aging/aerating for ~24 hours.
This is separate from what happens in a tank. In a tank, changes in pH are due to alkalinity, typically KH. Acids from driftwood, leaves, nitrification, etc. erode KH; pH falls. Coral, aragonite, limestone, bicarbonate increase KH; pH falls.
Do you know you KH Hendre ?