Chlorine Lock ?

[mjsboone]

It will be a week before we are able to get the more extensive testing kit. My question now is, do we keep adding the bleach every night and for how long? Would this be the routine from this point forward or at some point do you just add the bleach on a maintainance schedule? The water is clearing nicely, but we see slight algea by the ladder and a little in the shaded corner of the pool.

[CarlD]

Just keep doing what you are doing. WM and PD know best. I'm surprised there isn't a WalMart near you with the HTH 6-way drop test kit. That's the best thing short of the Taylor K-2006.

WaterMom uses bleach in her pool. I use Liquid Chlorine in mine. Same thing, but there is ONE store that sells LC in 5 gallon carboys that turns it over so fast their stuff tests out at 14% though they nominally sell it as 12.5%. What's the difference between that and 8.25% chlorine bleach? Only in the amount of chlorine added to your pool.

If your pool was 10,000 gallons, one jug (121 ounces) of 8.25% bleach will add 7.8ppm of chlorine. But if you add 1 gallon of 12.5% LC, it will add 12.5ppm of chlorine. (you need twice as much of each to get the same addition of chlorine in a 20,000 gallon pool). That's the only difference between bleach and LC.

As for bleaching your liner, you need to really raise your chlorine level very high before you do that--and EVERY kind of chlorine can do it regardless of the source.
Generally, if you "shock" your pool to the recommended level based on your stabilizer (aka CYA) level, you have NO fear of bleaching your liner. However, over the years, the sun WILL fade it anyway. Personally, it's not a big concern of mine as long as it's not weakened. But that's me.

[mjsboone]

Just found out that Ace Hardware carries HTH 6-way drop test kit. I've been everywhere today looking for ANY test kit and ended up at the pool shop buying the very basic kit to get by. I fail to understand why the stores in South Carolina, where the pool season begins in April and ends in October, do not stock pool supplies once you hit July. It is slim picking! Off to Ace Hardware tomorow. Continued thanks to all for the advice!

[PoolDoc]

Nobody wants to carry expensive inventory all winter.

Keep up with the bleach till you have test results from the K2006. The 6-way will help -- you can test stabilizer -- but in your particular situation, accurate measurement of FC vs CC is needed, and only the K2006 will give you that.

But, the 6-way is compatible and useful, so don't regret having both. Do post CYA results from the 6-way -- watch the Taylor video for the K2006 CYA test; it's almost the same as the 6-way.

[Watermom]

Adding two jugs this evening should have added just under 7ppm. You report only 1.5-3ppm only an hour after testing which means your chlorine is being eaten up pretty quickly. If it were my pool, and especially since there is algae, I'd add more tonight and probably more than 2 jug doses. Ben, do you not agree with this?

[mjsboone]

Well, this morning brings zip zero chlorine. I want to say that I could see a tinge of yellow in the test bottle, but not enough to register on the lowest level of the vial. Since I don't have the fancy test kit, I used the test strip to check stabilizer and it indicated it was in the "ok" range. My stockpile of bleach is now gone so off to the store again. The water is clear, thank goodness. Nothing worse than looking out your windows and seeing a cloudy pool or green pool for that matter. Now I do realize that I need a better kit, but will not have that for a while. What will actually resolve this chlorine lock and what kind of time frames am I looking at? Thanks everyone.

[BigDave]

I haven't heard of the hth 6-way drops kit anywhere but wall mart; it's not on ACE's website.

The test strips for CYA are useless - they just don't work. No one here can advise you regarding your pool without accurate measurements. I'm sorry.

The only thing you can really do without a K-2006 is keep dumping bleach in the pool and hope it stays clear - maybe take OTO reading and dose bleach multiple times a day.

Please remember: chlorine lock doesn't exist - it's just something you were told by someone afraid to say "I don't know".

[PoolDoc]

Well, this morning brings zip zero chlorine. I want to say that I could see a tinge of yellow in the test bottle, but not enough to register on the lowest level of the vial.

Overnight chlorine loss almost certainly indicates that there is something in the water that the chlorine is oxidizing. The only solution to this is to chlorinate till it's gone OR to drain and refill. (Remember, most inground pools cannot be drained safely without special precautions). You can do the bucket demand test to see how much chlorine it's likely to require: http://pool9.net/bucket-demand/

Unfortunately, we can't tell you WHAT is in the water. We'd know a little more, if you had the K2006. I can tell you that your problem originated in one of two ways: EITHER, it's something the pool store has been selling you -- and yes, stores sell MANY worse-than-useless products -- OR it's partially degraded stabilizer (cyanuric acid), resulting from a period of biofilm (bacterial slime) activity in your pool.