Tested pool first time, strange CYA reading

Welcome!!

I hope you transposed the numbers and your pH is 7.2

Yes, your CYA test is showing very high CYA. This is not uncommon for a pool that someone takes over and the previous owner fed it a diet of 3" tabs all the time.


100 is the limit of the CYA test, so you have to do a diluted test. While the full instructions are in the Pool School, here is the short version. Mix 50% pool water with 50% tap water. Use this mixed sample as your test water. If still at a 100 you will need to dilute more. The problem is that when doing a diluted test not only do you multiply the rage of the test you multiply the error rate of the test, so results are a ballpark - not an absolute. Here is a great chart by JamesW to explain dilution rates and what you multiply the results by to get an approximation of your CYA level.

Pool water......Tap or distilled water.........Multiply result by

....1...................1................................2
....1...................2................................3
....1...................4................................5

The pool guy coming by weekly is why the CYA is high. Time to take over for yourself.



ow much Pool School have you read? Start with these: