On Thursday, May 29, 2014 1:36:40 AM UTC-4, Danny D. wrote:
Tekkie® wrote, on Wed, 28 May 2014 19:27:16 -0400:
I'll be over for my yearly dip.
It's almost ready for your annual dip!
So far, it has taken three weeks (elapsed time) to almost fill
the pool from the well water because the well just couldn't put
out more than about a thousand or two thousand gallons without
running dry.
https://c2.staticflickr.com/4/3721/1...804dcb1c_b.jpg
I've snaked all the bottom drains, popups, and side vents:
https://c1.staticflickr.com/3/2922/1...63173085_b.jpg
One huge technical problem I just solved today was how to
dissolve 12 pounds of professional cyanuric acid powder in
one sitting!
https://c2.staticflickr.com/4/3717/1...d6f33721_b.jpg
As you may know, CYA has a low solubility in water (2g/l@25ºC).
That means only 1/10th of a pound can dissolve in my 5g bucket:
https://c2.staticflickr.com/6/5517/1...f36835bd_b.jpg
After making a few mistakes, I realized is that this professional
powder cannot be applied wet, as the retail granules are!
It must be applied dry!
Otherwise it cakes instantly!
https://c2.staticflickr.com/6/5159/1...2b59f88c_b.jpg
I finally figured out how to keep the cyanuric acid powder in
a suspension, so that it can be poured into the pool like milk!
https://c1.staticflickr.com/3/2901/1...c71a9dd0_b.jpg
The result is a dispersing "cloud" of water-separated particles:
https://c2.staticflickr.com/4/3799/1...6f8fb243_b.jpg
But, it took a few experiments where all I got was caked CYA on
the floor of the pool before I figured out the physical chemistry
of a substance that turns into instant cement with water!
https://c1.staticflickr.com/3/2898/1...2c16a580_b.jpg
Apparently the cyanuric acid is slow to dissolve because of the
amount of energy it takes for water to dislodge a CYA molecule
from its crystal structure (analogous to an activation energy for
chemical reactions).
https://c1.staticflickr.com/3/2911/1...b14c9b48_b.jpg
The rate of dissolving has a far greater dependence on the
surface area of the granules and on the circulation of
water around them. Finely crushed CYA dissolves more quickly
than the retail granules, though it is so light that it can't
readily break the surface tension of water and ends up floating
on the surface when I apply it by shaking it out of a dry net:
https://c2.staticflickr.com/6/5113/1...9d55434f_b.jpg
So, I learned a lot about how the pros apply cyanuric acid
powder (which, I might add, isn't easy to buy because it's not
apparently sold to the general public):
https://c2.staticflickr.com/4/3754/1...f9945a46_b.jpg
Most folks use the regular CYA, not powder, put it in a nylon
stocking or old tee shirt and toss it in the skimmer. It still takes
a long time, week+ to dissolve. Another theory is just add it to
the skimmer, let it wind up in the filter and the water will supposedly
dissolve it there as long as you're not backwashing anything soon.
I've never done it that way, because I figure after it goes into the
filter, it could be soon covered up by some other debris and might
not dissolve. But folks who do it that way have measured in the pool
and according to them it works.
Actually, it's not much of a problem here in the northeast. Between
pumping out rainwater, backwashing, winterizing, etc about the right
amount of wate gets taken out so that using trichlor the cya stays in
the right range and you typically don't have to add any, unless you're
draining/refilling like you did.