Hot Tub Question

[Robin N]

Drained and cleaned the hot tub. Can I go by the best guess chart for the amount of bleach? I used the calculator to figure out my gallons - looks like 735.

[waterbear]

If this is an indoor hot tub then you DO NOT want any CYA (stabilizer) in the water. If the hot tub has it's own filter and pump you might want to consider bromine instead of chlorine. If it share the pool water you don't have a choice but stabilizer is NOT good in a hot tub that is not exposed to the sun. If you decide to use chlorine and there is not CYA in the water then just keep the chlorine leves at about 4-6 ppm with bleach. I would try and find out more about the filtration and plumbing between the hot tub and the pool. Also, If this is an acrylic tub with molded seats the volume of water is going to be less than if it were a tub that had an even depth all over. What are the dimesions and shape. Most acrylic hot tubs are under 500 gallons and your typical 6 foot round is about 250-300 gallons!

[Robin N]

Waterbear,

Thanks - hot tub is indoors, so I'll skip the CYA. My husband is back in town so I can ask him about the pump and filter, but it appears to have it's own system, after looking at it. I measured 7' x 7' square - I measuered the depth from the seat at 22". I didn't measure the deepest part. It has a "double recliner" on one side, then 4 molded seats. Does the P234 work the same with the hot tub?

[waterbear]

Waterbear,

Thanks - hot tub is indoors, so I'll skip the CYA. My husband is back in town so I can ask him about the pump and filter, but it appears to have it's own system, after looking at it. I measured 7' x 7' square - I measuered the depth from the seat at 22". I didn't measure the deepest part. It has a "double recliner" on one side, then 4 molded seats. Does the P234 work the same with the hot tub?

I would guess that you have about 400 gallons, give or take. Bromine has some definite advantages in an indoor spa. You might want to consider it. You can use the PS234 with the spa and use it with either bromine or chlorine. If you decide to use bromine then just multiply the Total chlorine readings by 2.25 to get the bromine reading...also you will not have to test for free chlorine at all since bromamines are not an issue.

[DaveD]

I seem to remember there used a portion of this site for hot tubs though I can't find it anymore. My Dad just put in a hot tub and was asking similar questions. I've seen tubs foam with Bromine and I personally have never liked it's odor. My suggestion to him was going to be chlorine. Since the tub is usually covered and indoors, I thought the chlorine level could be run lower since it shouldn't vary as much as an outdoor pool. Thought 1-3PPM more than adequate.

Am I all wet? Does chlorine off gas too much with the temps? Out side of keeping the water slightly descaling or neutral on one of the scaling indices and pH in 7.6-7.8 range, what else would you need?

[waterbear]

To the best of my understanding the chlorine level still needs to be higher than that because of the elevated temperatures of the hot tub. You want to make sure that you do not use any form of stabilized chlorine (dichlor) in an indoor tub. Bleach is going to be your best chlorine source. 4-6 ppm should be fine. TA will be constantly decreasing because of the airation and pH will be rising. Start with the TA high....maybe about 180 ppm for an acrylic spa and keep the calcium in the neighborhood of around 100 ppm and there should not be any major scaling problems. Be sure to shock after each use and to drain and refill the tub about every 1-3 months depending on usage. The smaller water vs. bather load really makes this necessary.

[DaveD]

If you were running bromine - what level would you run? Keep pH in what range, 7.5-7.8? If there is an ozone generator, can you run lower levels of either bromine or chlorine since the ozone will do a majority of the work and the bromine or chlorine demand would be significantly lower - decreasing the chance of a major swing in bacteria levels or need for higher ppm levels?