So i tested my hot tub water last night. first with the basic OTO test and the colour had so slight yellow, seemed like none. so then i tested again with FAD/DPD test and added the R0870 powder and the colour did not change at all.
So prior to soaking i added 5 oz of 10.8 Liquid Chlorine. Left it for 30-45 min. figured the Chlorine should have been around 8.5ppm roughly.
My wife and i went in the hot tub for about 30 min. When we were done, i added 4 oz of liquid chlorine.
Tested about 1 hour later and it was over 20ppm. I stopped counting.
I thought you added roughly 2 oz per person per hour. so i added twice that so that it would be at a good level afterwards
I'm wondering if my R0870 powder is not good? some of it is a bit clumpy. But then again the OTO test also showed very little 1ppm or less.