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Thread: Trichlor Tablet in Skimmer of Hot Tub

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    Trichlor Tablet in Skimmer of Hot Tub

    I want to use the Bleach method in my pool but have to get the CYA level to 30 first. So I wanted to know if I could put a 3" Trichlor Tablet in my skimmer basket for one day and test and then add again until I get to 30. My TA is 110 and my PH is above 8.
    18 x 40 inground pool, 27,000 gallons Built in 2012. Vinyl with a SWG. SwimClear cartridge filter by Hayward C3030, Aqua Rite SWG T-Cell 15. Hayward SP2610X15.

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    Re: Trichlor Tablet in Skimmer of Hot Tub

    It will take too long just doing it this way if you are very far below 30. Much easier to purchase some and add it.
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    Re: Trichlor Tablet in Skimmer of Hot Tub

    Sorry. I meant my hot tub not my pool. My pool is closed . Any concerns doing this in my hot tub
    18 x 40 inground pool, 27,000 gallons Built in 2012. Vinyl with a SWG. SwimClear cartridge filter by Hayward C3030, Aqua Rite SWG T-Cell 15. Hayward SP2610X15.

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    Re: Trichlor Tablet in Skimmer of Hot Tub

    What is your Cya now?
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    Re: Trichlor Tablet in Skimmer of Hot Tub

    It is zero
    18 x 40 inground pool, 27,000 gallons Built in 2012. Vinyl with a SWG. SwimClear cartridge filter by Hayward C3030, Aqua Rite SWG T-Cell 15. Hayward SP2610X15.

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    Re: Trichlor Tablet in Skimmer of Hot Tub

    If you knew your circulation pump was running all the time then the Trichlor would be OK [EDIT] only if it's a small 1/2 ounce (1/4") tablet [END-EDIT], but usually in a spa it's not running all the time so would be a little risky given the acidity of Trichlor. Usually for a spa you use Dichlor initially to build up the CYA and then switch to bleach. See Using Chlorine in a Spa and note that you need to get your TA down to around 50 ppm and should also add 50 ppm Borates (usually from boric acid). Spas have a lot of aeration and tend to rise in pH so you need to have the TA be low and need the borates for additional buffering.
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    Re: Trichlor Tablet in Skimmer of Hot Tub

    Is this an in-ground spa or a portable, factory-built spa (i.e., HotSprings, Sundance, Jacuzzi, Cal Spa, etc.?)

    I ask because you list the pool as having a vinyl liner and I can't say I've ever seen an in-ground spa associated with a vinyl liner pool.

    If your tub is self-contained and covered all the time, it doesn't need CYA (no UV breakdown) and you definitely should not use Trichlor.

    If not a portable spa: disregard.

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    Re: Trichlor Tablet in Skimmer of Hot Tub

    Quote Originally Posted by HotTubTips
    If your tub is self-contained and covered all the time, it doesn't need CYA (no UV breakdown) and you definitely should not use Trichlor.
    Welcome to TFP!

    The above statement is incorrect because CYA is indeed needed both in a spa that is covered as well as for indoor pools, but the level of CYA need only be 30-40 ppm for the spa and 20-30 for indoor pools. The reason is that CYA not only protects chlorine from breakdown from the UV in sunlight, but also significantly moderates chlorine's strength (by an order of magnitude or more). If you do not have any CYA in the water, then the chlorine will be too strong and will oxidize swimsuits, skin and hair faster, will outgas faster and oxidize hot tub covers faster, will corrode metal faster, will produce disinfection by-products more quickly (and more nitrogen trichloride), etc.

    Normally for residential spas, dealers recommend Dichlor and that adds CYA to the water, but the problem is that if only Dichlor is used, then the CYA level builds up and the chlorine becomes less effective to the point that it is unable to oxidize bather waste quickly enough and the water turns dull/cloudy. Also, the risk of getting hot tub itch/rash/lung increases when the CYA level is high since the active chlorine level is then too low. This is why, for chlorine, we recommend the Dichlor-then-bleach method since that builds up the CYA level when you initially use Dichlor, but then you switch to using bleach after that (except for one day a month to make up for the slow oxidation of CYA by chlorine).

    It is true that Trichlor is risky to use because it is so acidic and in a spa it dissolves too quickly to be used as with a pool where it can slowly dissolve in a feeder. Also, I should note that it doesn't take much Trichlor to raise the FC in a spa -- a 1/4 ounce small (1/2") tablet would raise the FC by 4.9 ppm in 350 gallons while an 8 ounce large (3") tablet would be far too much and should definitely not be used. Thanks for reminding me to look again at what the OP wrote about the Trichlor he was going to use.
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
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    Re: Trichlor Tablet in Skimmer of Hot Tub

    Quote Originally Posted by jewing
    I want to use the Bleach method in my pool but have to get the CYA level to 30 first. So I wanted to know if I could put a 3" Trichlor Tablet in my skimmer basket for one day and test and then add again until I get to 30. My TA is 110 and my PH is above 8.
    I just saw you are talking about a 3" Trichlor tab -- that is WAY too much for a spa so you should not use it. If it were a small 1/4-ounce (1/2") tablet, that would be different.
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

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    Re: Trichlor Tablet in Skimmer of Hot Tub

    Ok. Sorry I didn't give more details about my Spa. It is a self contained fiberglass spa built by the manufacturer. I put one of the tablets in for about 12 hours last weekend and then took it out. So not a lot dissolved but it did raise my Chlorine extremely high.(Well over 30 I estimate). So big mistake. I did it before i got the answers to my question. again, big mistake. The good news is that my chlorine is back down to 3 and the rest of my water is balanced except my CYA is not registering yet on my Taylor K-2006. So i am now using the Dichlor and adding a little at a time and testing my CYA and Chlorine.

    My question is, with the little amount of the tablet I did use, should I worry about the acid impact and drain my spa and start over or do you think the little amount of time I had it in the skimmer was not enough to worry about. The tablet didn't lose more than 1/4 in while it was in there.
    18 x 40 inground pool, 27,000 gallons Built in 2012. Vinyl with a SWG. SwimClear cartridge filter by Hayward C3030, Aqua Rite SWG T-Cell 15. Hayward SP2610X15.

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    Re: Trichlor Tablet in Skimmer of Hot Tub

    Test your pH and if it's low then raise it. No need to drain the spa -- just balance the pH. Test the TA while you are at it and if it is also low, then you can use some pH Up (same as Arm & Hammer Super Washing Soda) to raise both, but if you are planning on using the Dichlor-then-bleach method then remember that you will only have the TA at around 50 ppm and will also add 50 ppm Borates.
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

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    Re: Trichlor Tablet in Skimmer of Hot Tub

    Is Lithium Hypo Chloride ok to use similar to liquid bleach?

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    Re: Trichlor Tablet in Skimmer of Hot Tub

    Yes, but it's VERY expensive. If you've already bought it and can't return it then it's a sunk cost so you might as well use it.
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

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