how to lower if I need to? alkalinity of 170

[CarlD]

While Steve is right in explaining what T/A does, the levels that are recommended here are pretty simple:

If you have a gunite/concrete/tile pool: 80-125ppm
If you have a heater or SWG, generally the same, but the metal composition of both can affect the numbers. Still, 80-125 is safe.
HOWEVER, if you have a vinyl pool, without a heater or SWG, you can safely go as high as 180ppm without worry. That's a ballpark number of course. You are pushing your luck at 200ppm, especially if that reading is taken at a lower pH.

While T/A is a "stabilizer" for pH, it DOES go up and down as pH moves. T/A doesn't prevent pH movement, it just makes it harder to happen. It keeps pH from pogo-ing up and down.

So if you are at the suggested upper limit with a pH of, say, 7.1, then, if your pH rises to, say 7.8, your T/A will probably go well over the max, opening the potential for problems.

This is why 100ppm is such a good target--there's lee-way either way. For a vinyl pool, you have a far vaster range.

I repeat: a reading of 170ppm in a vinyl pool without a heater or SWG is FINE and can be left as is with no impact.

[river-wear]

Okay, I found this thread trying to find an answer for my situation and still feel a little lost. Please help. I have Ben's kit and got the following results:

FC- 3
CC- 0.5
pH- 7.5
Alk- 190
Cal- 140
Cya- 35-40 (I'd guess 37)

I have a heater and a SWG so I'm worried about the high Alkalinity. I just filled the pool about 2 weeks ago after a major remodel. It's concrete with a fiberglass lining. My Autopilot manual says the TA should not exceed 150.

I saw the other posting referring to a procedure to be followed carefully, but haven't found that procedure just yet.

[Watermom]

Here is a link to the directions for lowering alk.

http://www.poolforum.com/pf2/showthread.php?t=191