Opening With Chlorine, Shock Concentration

[rossmic]

I have a 22 X 44 pool that calculates out to 195,750 L volume. When I use the calculator, it shows I only need 9.8 L of bleach to get the 3 ppm suggested chlorine concentration. I'm just opening and want to shock the pool, what chlorine ppm should I go for when opening? When I went to the pool store last year and purchased their liquid concentration, they gave me 2 5 gal. containers.

[chrisexv6]

Depending on your CYA level, I believe you want to start high, probably 10-15ppm of chlorine as a startup "shock" level. I think thats based on a decent CYA value (i.e. 30). You have to adjust up if CYA is higher than that.
Also, might help to test for combined chlorine (CC) reading. If you have any CC above .5, you want use the CC level to calculate your "shock" level (I believe the suggested formula is roaming around the forums somewhere....search for "breakpoint").

I actually have my pool around 20 ppm right now. Been keeping it that way to make sure I get every last bit of algae that grew (we get lots of sun directly on the pool in the winter, combined with a mesh safety cover = decent amounts of algae no matter how early I open).

Keep that shock level for a couple days to make sure everything dies. Brush the floor and walls if you can, and vacuum to waste a couple times. After keeping the level, and if the CC reading is back down, let the FC level lower naturally, and then maintain your 1-3ppm.

-Chris

[brent.roberts]

Why do you want to shock ??

I would suggest you start the pump/filter and after a few hours then run the standard tests, then according to what you see, decide if you need to shock.

If there is no algae, and your CC is less than 0.5 PPM there is no reason to shock that I know of.