Free Chlorine?

[brewski]

I have owned my hot tub now for just over two months and I must say it has been more fun than I ever imagined. My wife and I enjoy sitting out in the evening especially when the stars are out and find it a great way to relax after stressful days at our jobs.

I do have one question for all the spa experts howevr. We regularly test our spa 2 times a week with the spa test strips that were provided to us and almost always the test strip indicates that our "Free Chlorine" level is on the low side. I'm not sure what is meant by "free chlorine" and I'm aalso not sure as to the best way to bring the chlorine level up to an acceptable level. We have added the "shock" treatment that was given to us with the start up chemical set but I wonder if we shouldn't be doing something else?

I'd appreciate any help you all can offer in this regards.

Happy tubbing!!!

Brewski

[HotTubMan]

When measuring Chlorine levels, one can test total chlorine/combined chlorine and free cl.

Total or combined measures how much cl is "used up" but still present in the spa. This by-product of organics and cl is know as a chloramine. Free chlorine is cl that is availible to work.

By shocking, you seperate the organics from the cl. The organics leave the spa through oxidizartion (aka shock) in the form of a nitrogen gas. This is why you need to leave the cover off when you shock.

[Perk1]

Damn Brewski, I thought you were giving away 'Free' chlorine....I got all excited....LOL....

[windsurfdog]

When measuring Chlorine levels, one can test total chlorine/combined chlorine and free cl.

Total or combined measures how much cl is "used up" but still present in the spa. This by-product of organics and cl is know as a chloramine. Free chlorine is cl that is availible to work.

By shocking, you seperate the organics from the cl. The organics leave the spa through oxidizartion (aka shock) in the form of a nitrogen gas. This is why you need to leave the cover off when you shock.

HTM,
Just a point of clarification.....
As I read your post, it reads to me that you are saying combined chlorine and total chlorine readings are one and the same.  Do not chlorine readings follow the following equation?
free chlorine + combined chlorine = total chlorine
My apologies ahead of time if I just read your post wrong.

[brewski]

So how long should I leave the cover off when I shock?

[windsurfdog]

So how long should I leave the cover off when I shock?

I normally leave mine uncovered for at least 30 minutes after a dichlor shock....