Chlorine Levels do not make sense

[outdoor]

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.

 

[JoyfulNoise]

Any ozonator in the spa?

That much chlorine should have raised your FC by about 14ppm. So your measurement seems a little high. However, I doubt your R-0870 powder is bad. It can get clumpy if it is not stored properly or exposed to excess humidity. Typically, the OTO drops are not very accurate at all so even if they give a hint of yellow you could still have essentially 0 FC. The FAS-DPD test is telling you that the tub had 0 FC in it and I would believe that over the OTO drops any day of the week.

2 fl-oz of 10% is probably about right in terms of volume but remember that it is not a hard & fast rule. Everyone's tub acts a little differently and people vary in how much bather waste they produce (I know some people that actually shower BEFORE they get in the tub to keep the water as clean as possible). So you have to experiment a little with what amount of chlorine works best. And, if it wasn't clear from the article, chlorinating your spa manually with bleach is really a daily ritual as hot tubs can lose all of their chlorine in as much as a single day. So you need to usually test a lot in the beginning to get a feel for how the tub reacts to bleach.

I asked about the ozonator because, if the tub has one, they will cut down on the amount of bleach needed to oxidize bather waste.

 

[outdoor]

Any ozonator in the spa?

That much chlorine should have raised your FC by about 14ppm. So your measurement seems a little high. However, I doubt your R-0870 powder is bad. It can get clumpy if it is not stored properly or exposed to excess humidity. Typically, the OTO drops are not very accurate at all so even if they give a hint of yellow you could still have essentially 0 FC. The FAS-DPD test is telling you that the tub had 0 FC in it and I would believe that over the OTO drops any day of the week.

2 fl-oz of 10% is probably about right in terms of volume but remember that it is not a hard & fast rule. Everyone's tub acts a little differently and people vary in how much bather waste they produce (I know some people that actually shower BEFORE they get in the tub to keep the water as clean as possible). So you have to experiment a little with what amount of chlorine works best. And, if it wasn't clear from the article, chlorinating your spa manually with bleach is really a daily ritual as hot tubs can lose all of their chlorine in as much as a single day. So you need to usually test a lot in the beginning to get a feel for how the tub reacts to bleach.

I asked about the ozonator because, if the tub has one, they will cut down on the amount of bleach needed to oxidize bather waste.

No ozonator