CYA drain planned . . .

[pikeman]

My CYA level was measured about three times recently at 150ppm. I use a Rainbow test kit to measure FC, TA, CC, and PH, but don't have the reagent for CYA. I've been depending on the two pool stores where I buy my DE, Muriatic Acid, and Trichlor tabs. I don't entirely trust either of them, but to their credit heir numbers and mine are pretty close. To their credit, nether has tried to sell me "snakeoil" products.
The last set of numbers were:
FC 4.0
TC 4.0
CC 0
pH 7.6
hardness 170ppm
Alk 70ppm
Total dissolved solids 500ppm

Based on this I need to drain more than half my water. I've been waiting for some cooler, overcast weather and even rain, to keep the plaster from getting dried out. However, the person at one of the store told me I also need to pressure wash the pool. This is an additional complication because now this task is not feasible as an overnight activity.

I have read the articles on how CYA harms plaster and intend to accomplish this as soon as I get my pump fixed. (That's another story) So what is the deal on pressure washing? I'll drain the whole pool if it will save me this task. I am not looking forward to getting into the remaining water to accomplish this.
Thanks;
Pete

 

[JasonLion]

Unless there is some additional factor you haven't mentioned, there is no reason to pressure wash the pool. High CYA levels do cause problems, but they don't damage plaster or require pressure washing.

 

[spishex]

I think the plaster damage you're talking about was at very high levels, above 300ppm. What did they say pressure washing would accomplish?

 

[pikeman]

What did they say pressure washing would accomplish?

This young woman seemed to think there would be some sort of coating of CYA on the plaster. I don't see anything different about the plaster now than before the CYA overload, but thought it worthwhile to ask someone who would _really know_ as opposed to someone repeating information learned in a training class.

One of the things that really frustrates me is that I've never met a pool store employee who actually has cared for a pool!

I am really glad to know this because I wasn't looking forward to that task. As it stands, I am planning to begin draining as soon as it's dark and will be refilled ASAP. It's only going to be about 9K gallons to get the CYA load back where it ought to be.
Thanks for the advice.
Pete