I've had a 27' AG pool for 7 years. I have followed advice on Pool Forum for about 5 years. However I am more confused about pH and Alkalinity than ever.

For the past 7 years, I have tried to keep my alkalinity around 70 - 100. I have to periodically add some baking soda, but have been able to maintain it within reason. I typically have had to adjust my pH once a week or so as it gets higher each addition of bleach.

Last year I got too busy at work and accidentally let my alkalinity drop to 40. At the same time I noticed that I was not having to adjust my pH as often. So I did some bench tests with my water and it showed that the lower the alkalinity the LESS pH swing. This is exactly opposite what I have always thought to be true.

This spring I replaced my liner. I refilled my pool and decided I would try running with out adding any baking soda. My source water is very soft and has very little natural alkalinity or calcium. I added CYA to about 25, added bleach to maintain 3 to 6 ppm. After all the CYA dissolved (~3 days), my final pH was about 7.4.

I add about 3/4 gallon of bleach each night to maintin my chlorine levels. My pH is still at 7.4 after a month!

From a chemical standpoint, not having to worry about alkalinity yet having very stable pH is wonderful. My water is as clear as ever.

My questions are,

1) Is something going on with my water that makes it different than most others since running higher alkalinity is normal for most people?

2) Does running with low alkalinity cause me any problems such as increased rates of corrosion?

I appreciate your insight.

Jim