> They took the test and said your alkalinity is 26 you
> need to add 50lb of alkalinity up. Since I had just
> tested my self I did not believe the results. Besides
> this being low the wanted me to bring it up to 125
> minimum. This is strange to me too as I have always
> been told 80-120 for my plaster pool. I questioned them
> and they stuck to their guns. After I left I noticed on
> the sheet they had something called Adjusted Alkalinity
> which is much lower than Alkalinity - I don't know where
> this adjusted value comes from but it was too late to
> ask. They use a system called "alex" by Bioguard.
I believe Adjusted Alkalinity refers to the idea that the
cyanuric acid stabilizer in the water tests as alkalinity,
but doesn't behave that way with respect to scaling or
corrosion. They make an adjustment to remove the "false"
part of the alkalinity.
This is a controversial interpretation, and in my experience
since 1979, it just doesn't work in practice. The
alkalinity test in my Taylor kit produces results which seem
to work fine without making any adjustment. In other words,
I keep the unadjusted TA within the 80-100 range, and over
the years have had no scaling or corrosion. Also, pH tends
to be stable in that range.
If I add the large amounts of sodium bicarbonate which would
be called for by the adjusted number, it just makes the pH
spike, and I end up having to add acid every day to bring it
back down. Then when the ph has stabilized, I measure TA
and find the unadjusted value to be 80-100. So in my
experience, the whole exercise just encourages sales of
bicarb, then acid, only to leave you right where you
If Alkalinity Up is really bicarb, as I suspect, then their
recommended addition of 50 lbs is just silly. That would be
40 lbs in my 18.6K gallon pool, which is 10 big boxes of Arm
& Hammer baking soda. If you really needed that, I think
you would already be experiencing severe corrosion problems.
The other reading from store #1 that seems out of line is
the CYA measurement. Even with Richard's warning about the
accuracy of these tests, I don't see how they could get a
CYA reading that is essentially double what the other stores
If I were in your shoes, I would not let store #1 measure my
water in the future. It appears that all of their errors
(if that's what they are) tend to produce larger sales of
chemicals to you. Of course, that could be incompetence.
Sure it could.