Is the OTO test useless if I have high CYA levels?

[stratocaster1422]

CYA is currently in the 80 range. Using the charts here I am targeting FC levels of 9. Does this mean I can't use the OTO daily test as a gauge of levels? Do I now have to use the FAS-DPD test until CYA comes down and FC can be maintained inthe <5 range? I have been using test strips and as long as they are darker than 5 but slightly less than 10 I have been happy so as not to use up the powder quickly.

Can I "cut" the OTO test with my well tap water and multiply the results by 2? How accurate would I need to be on th half and half fill?

 

[Richard320]

Yes, you're stuck using the FAS-DPD tester. The OTO tester isn't all that exact to start with, and dilution makes it less so.

You can order refill powder and drops here: http://tftestkits.net/XL-Option-for-TF-100-p62.html

 

[Isaac-1]

I mostly agree with Richard here, but will say the OTO test does make for a quick easy sanity check of your ballpark chlorine level