On Apr 26, 12:57*am, "Danny D." wrote:
On Sat, 20 Apr 2013 22:14:14 +0000 Danny D. wrote:

Assuming the Costco available percentage is reasonable, it seems
the way to go (at $2/pound); but was just wondering if SMS knew
the best place to buy about 100 pounds of 3 inch trichlor tablets.

I bought the Costco trichlor tablets but found out it's 85% effective.
I also found out that we only have two effective percents for trichlor.
1. There's 90% available chlorine
2. And then there's 85% available chlorine

Price for working free chlorine should determine which you choose,
since there isn't really any other difference (other than some are
wrapped individually which I would find to be a pain).

- Costco & Lowes = 85% available chlorine
- Leslies & Home Depot = 90% available chlorine

So, my rough draft table is the following (unconfirmed yet):
- Costco $80/40 pounds * 100/84.65 pounds = $2.36/pound FC
- Leslies $80/35 pounds * 100/90.0 pounds = $2.54/pound FC
- Home Depot $60/24 pounds * 100/90.0 pounds = $2.78/pound FC
- Lowes $60/24 pounds * 100/84.95 pounds = $2.94/pound FC

Interestingly, we find the HASA liquid chlorine, even at the web
sale price of buy-1-get-1-for-just-tax in that same cost range:
$21.62/8gal x 1gal/9.7pounds x 1/10.8% by wt avail Cl = $2.58/pound FC

You've confirmed what I figured out some time ago. A lot of
people use liquid chlorine because they think it's the cheapest
form. Kind of what you'd expect, right? It's just chlorine bleach,
not made into a slow release tablet, etc. But here in NJ I came
to the same conclusion. That Costco price is about the best you
can do for tablets. And here liquid chlorine 12% is about $18 for
5 gallons and you have to return the empty container. So, the
tablets are significantly less expensive than the liquid.




Of course, the solid trichlor increases the cyanuric acid in the
pool at about the rate of 1.73ppm/pound while the liquid chlorine pushes
up the pH necessitating a bit more acid ... so there are additional
considerations other than straight cost per free chlorine to consider.

Yes, that is a big difference and will drive the choice in some cases.
Where we partially drain pools each
year and where we have more rain, the potential build-up of CYA is
much less of a problem. I've never had it occur.