HDX 5 Way test kit and shocking

Jan 18, 2016
2
Glendale
I'm a little confused on when to shock my spa based on this kits instructions. It doesn't say that there is a certain CC ppm that should be used to indicate the need for a shock but rather a large difference between CC and FC is the indicator. Is this correct? I see posts saying that CC should never go over a certain amount. Right now I just shock when the chlorine smell gets too strong after heavy or prolonged use.
 
I'm a little confused on when to shock my spa based on this kits instructions. It doesn't say that there is a certain CC ppm that should be used to indicate the need for a shock but rather a large difference between CC and FC is the indicator. Is this correct? I see posts saying that CC should never go over a certain amount. Right now I just shock when the chlorine smell gets too strong after heavy or prolonged use.

OK, it is time for you to do some serious reading in Pool School and do some searches on maintenance of a Spa. You don't need to "shock". Anything over about .5 CC indicates you need more sanitizer and that you are getting into an area where you want to stay out of the spa, until the cooties in the water are killed. The "chlorine smell" is, most likely, not chlorine, it is chloramine. That is another topic to research, in this forum.
 
Your first stop here should be ABCs of Pool Water Chemistry

The next stop should be How do I use Chlorine in my Spa (or pool)?)

In general, pool or spa sanitation advice that comes with your spa owners manual or on 5-way test kits should be ignored. If you're going to use TFP methods, they must be your only source. Using recommendations from multiple sources on pool or spa maintenance will only lead to confusion, frustration and poor results.
 
Yes. Spa bather load is immensely different than pool bather loads in terms the amount of waste generated (sweat, saliva... other unmentionables) versus actual amount of hypochlorite available because of a very low water volume. It's like having 400 people in your 30,000 gallon pool at the same time with water temperatures in the 100s. This is why it's necessary to bring FC levels up to over normal pool maintenance levels after soaks. Usually after a soak, nearly all of the FC is consumed so there's actually an FC debt. It can be thought of as having a negative FC, where there is more bather waste than the current FC can handle and you must target a higher FC just to get things back to normal maintenance levels.

If 4 people soak in a tub for 1 hour, you're going to have FC debt, unless you started with shock levels of FC. Targeting a shock level FC will overcome that FC debt and leave your FC likely above the minimum FC once again.

If there were a lot of people in the spa for a long time. I'll dose the spa, then recheck after 15-30 minutes and dose again to bring it up to shock levels until it sticks to make sure things are taken care of.
 
Ewkearns...chill out man it will all be ok. Everyone else thanks for the good info. I understand shocking to break up chloramine but what I didn't understand was the way this kit had me testing for it. The manual made it sound like after you got your FC reading you let the test water sit around for a few minutes and then whatever the water corresponded to on the color testing chart at that point was the CC level. I found some good info on the kit elsewhere that stated "The difference between Free Chlorine reading ( water color after 2-3 seconds ) and the Total Chlorine reading ( water color after 1-2 minutes ) is the Combined Chlorine reading.". So basically the second reading is actually the total chlorine ( not the CC ) and the difference between the 2 readings is the CC count. This makes allot more sense with what I'm experiencing with the spa.
 
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