cyanuric acid test

[david cyprus]

Hi,
i have done a tsst and the reading is well above 100 ppm, this is a pool with filter socks not a sand filter, i have been told i will need to drain half the pool water and refill to solve this problem .we are in cyprus and have very servere water shortages is there another way around this, i look forward to your reply

regards Dave

[chem geek]

You can maintain a Free Chlorine (FC) level that is around 7.5% of the CYA level. You'll need to more accurately determine the CYA level so dilute the sample with tap water and re-measure and then multiply by your dilution rate (so 50/50 dilution, you multiply by 2).

Another alternative that does not require the higher FC level is to use a supplemental algaecide such as PolyQuat 60 or a phosphate remover (though that can get expensive, depending on the initial phosphate level). If you use the PolyQuat 60 algaecide, you have to use it weekly without skipping a dose.

If it ever rains, you can use them to overflow the pool to help dilute it.

To stop the CYA from continuing to increase, you need to use unstabilized chlorine such as chlorinating liquid or 6% unscented bleach. If you continue to use Trichor pucks/tabs or Dichlor granules/powder, then the CYA will continue to increase. For every 10 ppm FC added by Trichlor, it also adds 6 ppm to CYA. For every 10 ppm FC added by Dichlor, it also adds 9 ppm to CYA. Calcium Hypochlorite (Cal-Hypo) does not increase CYA, but does increase Calcium Hardness (CH). For every 10 ppm FC added by Cal-Hypo, it also increases CH by 7 ppm.

Richard