How do I convert from chlorine tablets to bleach?

[reneep]

I have a 10,000 gallon fiberglass pool. I have an out of town friend who has been using bleach only in a 15,000 gallon above ground vinyl pool with great success and not much cost. I have asked around locally but can't seem to find anyone using bleach and of course the pool places all tell you not to do it. Any information, links to web sites on topic etc... much appreciated.

[Watermom]

Go to the sister site to this forum www.poolsolutions.com and read. Also, read through old posts on this forum. How do you convert? You simply quit using the tabs and start using bleach. Post some current water testing results from a drops based kit and let us look at them. Then we can help you get going from there. Welcome to the forum.

[Bleach=Chlorine?]

Read www.poolsolutions.com and also search this forum for the BBB Method. This consists of Bleach (Cl), Borax (PH+), and Baking Soda (TA +). The math is real easy with bleach - 5.25% bleach will raise the Cl level 5.25ppm per 10,000 gallons of water. There are two tools out there, Ben's Buest Guess CYA chart which helps adjust the cl level per stabilizer level and Mike's BleachCalc program that provides the conversions and dosages. Also, if you get a good set of testing #s for your pool members can start providing guidance. Thanks

[cleancloths]

Why convert? Why not use both!

I have found that using both is the easiest way to maintain the pool. Trichlor adss chlorine, CYA and lowers the pH. Bleach adds chlorine, and raises the pH. If you use both you tend not to have any need to adjust pH as they tend to balance each other out. If pH starts dropping use more bleach, if pH starts going up use more trichlor.

As for the CYA I find it also stays fairly constant using this method as you loose CYA over time from things like backwashing, splashing, etc... and also gain CYA-free water from rain dillution.

Don't mix trichlor and bleach together. I use trichlor in a feeder on the pump discharge and then manual add bleach as needed into the deep end of the pool.

[reneep]

OK, here are the numbers from the local pool company test this morning.
Ph = 7.4
Total Alkalinity = 88
Calcium hardness = 160
CYA = 172
Total disolved solids = 450
Free Chlorine = 7.8
Total Chlorine = 10.4

I know I need to let the chlorine drop. We are expecting lots of sun so that should take care of itself.

[CarlD]

OK, here are the numbers from the local pool company test this morning.
Ph = 7.4
Total Alkalinity = 88
Calcium hardness = 160
CYA = 172
Total disolved solids = 450
Free Chlorine = 7.8
Total Chlorine = 10.4

I know I need to let the chlorine drop. We are expecting lots of sun so that should take care of itself.

Seriously, SERIOUSLY WRONG assumptions!

Wow! If that CYA is right you should NEVER let your FC go BELOW 8ppm, and probably not below 10ppm. It's binding up so much chlorine that you need to run much higher levels just to keep your pool sanitary.

But since your FC=7.8 and your TC = 10.4, that means your CC is 2.6ppm. That means you are fighting something and need to shock your pool RIGHT NOW! With a CYA of 172, the shock level you need to go to is 25ppm of free chlorine. You need to keep it there until Total Chlorine is no more than Free Chlorine, which will mean that Combined Chloramines (CC) is 0.

You are on the brink of an algae bloom. Once you get that under control, you have two choices.
1) Run a high CYA/High Chlorine pool. That's not a big deal but you need a FAS-DPD test kit to test the chlorine at the higher levels and you need to stay on top of it. You are done using chlorine tablets and powders--they are what put you in this fix because they have been dumping CYA into the water. Use bleach or liquid chlorine.

2) lower CYA to reasonable levels. There are only 2 ways to do this, but the better is to drain most of your pool and refill. If you drain 1/2 and refill, your CYA will still be 85--very, very high. If you drain 3/4 of the water, the CYA will be about 45--at the high end of the normal range of 30-50ppm. Then again, you are done with tabs and powders and need to use only bleach or "liquid chlorine" to chlorinate.

Have another pool store confirm those numbers. The CYA and CC are SO high that I'm hoping, beyond hope, that it is a bad reading. But probably not.

[reneep]

Seriously, SERIOUSLY WRONG assumptions!

Wow! If that CYA is right you should NEVER let your FC go BELOW 8ppm, and probably not below 10ppm. It's binding up so much chlorine that you need to run much higher levels just to keep your pool sanitary.

But since your FC=7.8 and your TC = 10.4, that means your CC is 2.6ppm. That means you are fighting something and need to shock your pool RIGHT NOW! With a CYA of 172, the shock level you need to go to is 25ppm of free chlorine. You need to keep it there until Total Chlorine is no more than Free Chlorine, which will mean that Combined Chloramines (CC) is 0.

You are on the brink of an algae bloom. Once you get that under control, you have two choices.
1) Run a high CYA/High Chlorine pool. That's not a big deal but you need a FAS-DPD test kit to test the chlorine at the higher levels and you need to stay on top of it. You are done using chlorine tablets and powders--they are what put you in this fix because they have been dumping CYA into the water. Use bleach or liquid chlorine.

2) lower CYA to reasonable levels. There are only 2 ways to do this, but the better is to drain most of your pool and refill. If you drain 1/2 and refill, your CYA will still be 85--very, very high. If you drain 3/4 of the water, the CYA will be about 45--at the high end of the normal range of 30-50ppm. Then again, you are done with tabs and powders and need to use only bleach or "liquid chlorine" to chlorinate.

Have another pool store confirm those numbers. The CYA and CC are SO high that I'm hoping, beyond hope, that it is a bad reading. But probably not.
Wow is right. I had no idea it was in that condition. It looks great. Obviously I would prefer not to drain the pool. What happens if take about 12 inches out and refill then just let it sit and monitor? How long will it take for the CYA level to drop? Am I correct in that by using the tablets and having the chlorinte high I was also adding to the CYA level?

[aylad]

The CYA level is going to drop as you drain water from the pool, so immediately after you refill you should see what difference you're going to. And yes, by using the tabs, you were increasing the CYA level, at a fairly fast rate.

Janet

[MarkC]

If you only drain a foot and refill that won't make much of a difference to the CYA and you will have to repeat the process many times which is not very effective. I would bite the bullet and drain at least 3/4 of the pool. Make sure your water table is not high as you said you have a glass pool. 7,500 gallons should not cost you that much money. Like the above posters said use bleach from now on.

[aquarium]

Why convert? Why not use both!

I have found that using both is the easiest way to maintain the pool. Trichlor adss chlorine, CYA and lowers the pH. Bleach adds chlorine, and raises the pH. If you use both you tend not to have any need to adjust pH as they tend to balance each other out. If pH starts dropping use more bleach, if pH starts going up use more trichlor.

This makes a lot of sense. I just drained and refilled our pool and used bleach to get the chlorine up right away, and now using the tablets in the chlorinator for maintenance level. I plan on using the bleach for fast needs, like after a pool party and a backwash, and the chlorinator, well, to be lazy the other time. :p

[Watermom]

Just keep an eye on your cya level. Those tabs are convenient, but they are the very thing that gets people in trouble with too high of a cya reading before you know it.