Another shock question

[alapool]

I have been running the Pool Frog system for the last 2 years and I have decided after reading thru this forum that I am going to try using the bleach method. Sounds like a pretty easy solution.

So as I understand it you add liquid bleach every 2 or 3 days depending on your chlorine level. I personally don't want my levels to be above 3 ppm. The question that I have is when do I shock the pool? And does "shock the pool" mean that you just add a lot more liquid bleach?

Thanks for any help!

And THANKS FOR THIS WEBSITE!!!

[JohnT]

You shock the pool when the combined chlorine gets above about 0.5ppm, and you do it by adding enough bleach to raise the chlorine to the desired level. That level depends on your pool construction and CYA level of your water.

[alapool]

Let's assume I have a CYA level of 30.

So does that mean that when the combined Cl level is at .5 ppm, then the FC level is usually below 1 ppm? and I need to add enough CL to raise the FC level back to 3 ppm?

[waterbear]

According to Ben's "Best Guess chart
http://www.poolforum.com/pf2/showthread.php?t=365
with a CYA level of 30 your min FC should be 3 ppm and your max 6ppm. This is the range you need to keep it at normally. If your CC is greater than .5 ppm you need to shock by raising you FC to 15 ppm.

You can have CC at any level of FC. It depends on whether there is enough 'reserve' of FC to 'burn off' the contaiminents in the water and break down the CC. If you have an outdoor pool without a SWG a CYA level of 30 ppm is a good choice.

Be aware that the pool frog is a silver/zinc system and had probably added metals to your water. You might want to read the section of the forum on metals
http://www.poolforum.com/pf2/forumdisplay.php?f=139

[duraleigh]

Let's assume I have a CYA level of 30.

So does that mean that when the combined Cl level is at .5 ppm, then the FC level is usually below 1 ppm? and I need to add enough CL to raise the FC level back to 3 ppm?

Hi,

You're on the right track, but off just a little.

1. If you are not willing to keep your Cl a little higher than 3ppm, you may have some problems. That's just not quite enough residual sanitizer to keep your pool sparkling. You'll need to keep it somewhere between 3-6ppm with a CYA of 30.

2. If your CC test indicates greater than .5, yes, you "shock" the pool by greatly increasing the Cl.....up to 15ppm (with a CYA of 30). That burns up all the bad stuff in your pool, eliminates any odor you may have had, and restores your pool to a healthy condition. You then let the Cl come back down to it's maintenance level of 3-6ppm.

Dave S.

[alapool]

Ok, so I have read a the threads on too much copper in pool. I'll take care of this in another thread.

What kind of effect should I expect with the FC between 3 and 6 ppm? Will it cause the liner life to go way down? Will it cause skin irritations? Will it cause hair to become "straw-like"? These are issues I want to avoid. And what level does my CYA need to be if I want to keep the FC down between 2 and 3 ppm?

Also, how long does it take for the FC levels to come back down to the normal levels after I shock? When is it safe to swim again?

Thanks a bunch for your answers!

[waterbear]

Will it cause hair to become "straw-like"?
Thanks a bunch for your answers!

Having held both Barber and Cosmetologist licenses in the state of Florida for 29 years and having taught both professions I can tell you that it is NOT chlorine (at normal and even shock levels) that causes hair to become "straw like' but exposure to the UV rays of the sun. (You can sit by your pool and never go in the water and it will happen just as fast) Also chlorine will NOT cause the hair to turn green. That is from copper and I have outlined a safe and effective way to deal with that problem in another post
http://www.poolforum.com/pf2/showthread.php?t=326

[JohnT]

What kind of effect should I expect with the FC between 3 and 6 ppm? Will it cause the liner life to go way down? Will it cause skin irritations? Will it cause hair to become "straw-like"? These are issues I want to avoid. And what level does my CYA need to be if I want to keep the FC down between 2 and 3 ppm?

Also, how long does it take for the FC levels to come back down to the normal levels after I shock? When is it safe to swim again?

You won't even know there is chlorine in the pool at 3-6 ppm IF you keep your combined chlorine under control, which is easy. As to CYA levels, search for "Ben's Best Guess" on here and you will find details.

How long the FC will stay up is totally dependent on the situation. Sunlight, water condition, CYA level, bather load, cover use etc.. You are usually good to go the next day, but you need to test. I only shock about once or twice a year while we are swimming, so I don't have much to go on.

[CarlD]

Alapool:
You've gotten good advice here. You cannot rely on 3ppm as a max--as has been said, 3ppm is the MINIMUM for a CYA level of 30ppm--and running an outdoor pool with less than 30ppm of CYA is an invitation to an algae bloom--because chlorine will disappear due to breakdown and UV rays--sometimes in as little as 15 minutes.

You are probably looking at the EPA's rec that you don't swim in water above 3ppm of chlorine....Yet the same agency recommends that you don't drink water above 4ppm of chlorine--so at 4ppm it's not safe to swim in but it's safe to drink? Bit of a disconnect here, isn't there?

The minimum and maximum safe levels of chlorine depend heavily on the CYA level. Above 10ppm you can get some fading of bathing suits, but that's about it. Swimming pool liners aren't in danger until you reach 15ppm--but that is ONLY for low CYA levels. Again, the CYA affects the chlorine's action.

Your CC should always be zero. However, realistically, using Ben's kit, it frequently has a presence of less than .5--but unless you use the 25ml test (vs the 10ml test) you cannot tell if it's .2 or .4 or .5ppm. This could be due to pollen, suntan lotion--any slight contaminant--and it's hard sometimes to get that last bit of CC gone--I generally run my FC between 4 and 8ppm and that darn "<.5" shows up. But if it's clearly .5 or greater, you need to shock to get it down.

[Lenny]

However, realistically, using Ben's kit, it frequently has a presence of less than .5--but unless you use the 25ml test (vs the 10ml test) you cannot tell if it's .2 or .4 or .5ppm.

Carl,

Are you just talking about using the same test kit and just changing the proportions? I don't think I saw that listed as an option in the instructions.

Lenny