CYA Levels

[hooeld]

Last Friday I tested my water, and the CYA was very high, off the scale of my tester(WalMart).. I drained 1/2 the water (abt 13000 gal Gunite pool). Refilled, and took some water the the pool place Sat. Here is their numbers.
TC 5
FC 5
CC 0
PH 7.6
ALK 135
CYA 110


So I drained another 1/2 the pool, and used the last of my CYA test,

My numbers
TC .2
FC .2
PH 7.8
Alk 110
CYA 80

I added some Clorine, and got the TC to 6, and it has stayed there for about 24 hrs..

My first question, is shouldn't 2 drains of 1/2 bring the CYA down more than that? I also assume I need to get that down, then take care of the ALK/PH by Airation??

Thanks
Les
That does not seem to me that the

[mas985]

The Walmart CYA test only goes to 100 so how do you really know it was 110? Point is that it could have been at 160 ppm and with a 1/2 refill went to 80.

[larry2338]

Remember that the CYA test is somewhat subjective. If you take a sample in tomorrow, they may well read the result as 50 or 60 ppm. Or, even if you do the test, you may find it differs somewhat from what you read the last time.

[hooeld]

The 110 was tested at the pool supply place.. My test was 80 after a partial drain.. I'll have it tested tomorrow, and see where it is..

Thanks

[mas985]

The 110 was tested at the pool supply place.. My test was 80 after a partial drain.. I'll have it tested tomorrow, and see where it is..

Thanks

A pool store test is no guarantee. My pool store tests my CYA above 100 while my Taylor kit says 55. You are probably better off with your own test.