Use trichlor in spa?

[PaulR]

Split by moderator from HERE. jblizzle

Would trichlor in a floater work instead of dichlor, for the initial chlorine/CYA addition? I have a bucket of trichlor pucks which I now realize is a lifetime supply for the pool. But since the spa water gets changed out periodically, maybe it's only a multi-year supply...
--paulr

 

[spishex]

Re: How do I use Chlorine in my Spa (or pool)?

Yes, you can use trichlor tabs in a floater. If they're 3" you might have to work on finding something that will let it dissolve slowly enough since 3" floaters are usually designed for pool use, but other than that it will be fine.

 

[chem geek]

Re: How do I use Chlorine in my Spa (or pool)?

Normally it is recommended to not use Trichlor pucks in a spa, but it's mostly due to the acidity issues and feeders that add too much too quickly, as sphishex points out. With the small volume of water in the spa, I'd be very careful about using the Trichlor. Watch your pH very carefully.

In a 350 gallon spa, one ounce weight of Trichlor (about 1/8th of a 3" tablet or a single 1/2" tablet) will lower the pH from 7.5 to around 7.15 (with TA 100) while increasing FC by almost 20 ppm and CYA by almost 12 ppm.

Richard

 

[PaulR]

Re: How do I use Chlorine in my Spa (or pool)?

Well, 20ppm FC would be (ahem) shocking.
I guess I do have a lifetime supply of trichlor, regardless.
Thanks,
--paulr

Feb 8 added:
P.S. For grins I tried putting 1/4 of a partly used puck in my floater. The pH drop
and Cl increase meant I took it out after about 1.5 days. After another couple days,
the spa's natural tendency to increase pH (aeration) and drop Cl (usage) meant I
could put the floater back in (this time remembering to close most of the little slits).
I assume CYA is now at some reasonable point.
The spa needs daily checking anyhow, so it's really no extra trouble. The Cl and
pH fluctuations are within reason, just need to "rest" the floater as needed.