I have no idea Frog, we have been using pucks for about 10 years now in the same water. it's definately time to drain but as stated in my earlier post i'd like to wait another 6 months at least before doing so. unless I can find a cost effective answer to repairing the fiberglass liner.

for now I'll get the chlorine levels up to 20 or so will that cause any problems when people swim in it? I'm sure the kids will want to swim this weekend for sure. I guess the beach is another alternative but the traffic will be terrible.

If you mean 3:1 then I agree, since it is in the more accurate region of the test, and since the 1:1 mixture must have measured 105 (105X2 is 210)on the test vial. But they are both close and very high. Course the 3:1 is also more diluted, so there is some error there...but then again the 1:1 used less water, so the ratio has more potential error....

It's not 128 then. 128ppm CYA is doable in a year/season of pucks if it's long enough. Years of use with the same water... I'd go with the higher number personally. You have obviously backwashed and refilled some over the years so it's not going to be a sum total equation, but it'll be higher than 128 for almost sure.

It is said that it's safe to swim up to shock level for your CYA level. So, 20ppm should be fine if you go with the 220ppm value. I don't know how you'll enjoy shocking should you need to, at 220 it's an enormous amount of chlorine that will be needed. I don't think there is a CYA chart that shows chlorine levels for that high of a number however the pool calculator shows it at 17 minimum, 25 high target, shock is 45... Ouch!

Can you do a partial drain right now? 30% maybe?

Hold on...maybe I am missing something.

So the measurement gave 110 ppm in the vial, so the "real" pool water is 220?

So the numbers we are comparing are 128 and 220? That is a long way off...hmmm....

20 ppm is going to take quite a lot of bleach, but it is still below shock level for 128, so it is plenty safe.

You might want to consider having a reverse osmosis treatment done instead of draining and refilling. Here is a company that is in southern California.

http://www.savewatersd.com/

Linen yes we are comparing 128 and 220 between the 1:1 and 3:1 tests that why i was confused about the multiplier if you ha said tht a 3:1 ratio uses a 7x multiplier then the results wouls make sense

James Thanks for the link I'll look into that to see what it costs and how the process works. it's definately an option

asnother question how long do you think i will take for an algae breakout ifI just kepy the FC levels at 4 - 5? reason im asking is that I have been off the pucks for three weeks and havebeen maintaining a 4-5 FC level using bleach and the water looks pristine.

thanks

It can't be predicted. We use values that are known to disinfect and prevent algae blooms. If you choose not to use those levels, there's no real information we can provide you about how it'll go because we don't let our pools fall that low.

I had an algae bloom about two weeks ago. I'd let my pool fall below minimum once, a week prior. I can assure you everything was great till the day it went bad. And then it went bad fast. I lost 7ppm in about 16 hours. My pool was at 0 by 6pm that day. I NEVER loose more than 4ppm even with sun and swimmers. I had to shock my pool for the first time since switching to BBB (2 seasons now).

I maintain my pool religiously. I use the recommended levels taught here. When I didn't do that, I had a bloom. I dunno, it's hard to say when/if you'll have a bloom but chances are that you will eventually. 4-5ppm is lower than I'd ever maintain my pool at, my CYA is 40.

Understood. Im just trying to justify the drain to the wife lol. She doesnt understand chemistry and says it looks great I am dreading the amount of chlorine I'll have to use to maintain a level of 20 sO I'll try and maintain the current level and see what happens

That is a lot of chlorine to maintain lugging jugs of bleach/liquid chlorine. You could pile the empty jugs up in front of the door or someplace so she can see it easily
You will get sick of it, and I would guess you will eventually have to deal with algae. At that point you will end up doing a drain and refill, meanwhile you have spent a lot more than needed on bleach. Having to prove the the wife, you need it, will cost you more money than doing the drain now. Is your water expensive?

By the way when measuring CYA at 100+ there is a +/-30 ppm accuracy. At 90 and below there is a +/-15 ppm accuracy. This may account for the difference in measurement. I think I am believing that lower CYA value more, if you are pretty sure your parts were equal in that method...

yes Linen, in both methods the parts were equal and I agree that I will eventually have to drain it. I just received an answer on how to repair the fiberglass liner so I figure I will be draining it soon as the repairs wont be that expensive. are there any concerns with draining it through the main drain and backwashing the water out onto the grass? I'm not sure how much the water is but i'm sure its cheaper than the cost of all the bleack I'd be using to maintain the FC levels.

Sounds like a good plan.
I backwash onto my lawn and it has not caused any problems.

Just a note. I'd use the waste setting if you have one instead of the backwash setting, to drain the pool. If you don't have one I'd think about removing the internals so nothing will get trapped inside the filter. Maybe an unnecessary step but just a precaution.

question regarding the backwash i have a 2" opening at the valve. If I were to buy an adapter to convert it to a garden hose outlet and drain it through there would it cause any problems to the system due to pressure issues? I was thinking of using a garden hose with a sprinkler on the end to water the yard and spread the water out over a bigger area

A sprinkler would be too much flow restriciton on a pool pump. Your pressure would get very high, flow rate get very low, and backwashing would not work properly because of the low flow rate. Perhaps eight sprinklers plumbed in parallel?

I'll head to the hardware store and see if there is a 2 inch sprinkler worst case I can make my own by drilling some holes in a PVC pipe I guess