Should I raise my cya?

[PoolDoc]

Keep in mind that bleach at Sams or Walmart is likely to be fresher, and cooler, than bleach at a pool store. Take a look at their tank -- if its black poly, in the Arizona sun, it's VERY unlikely that it arrives at your pool at the rated strength.

Another test is to 'take the temperature' of the bleach just after buying it. If it's above 90 degrees, it may be 4% bleach.

But the best test -- if you have a K2006 -- is to dose the pool with equal doses of the various bleaches, in the late PM and test the pool FC level just before, and an hour after, dosing.

[dubbedout]

Yeah, I understand that most of the bleach/LC is trucked in and loses some strength. Most stores keep their supply indoors at least, except for one store I ran into that keeps it sitting outside in the "shade". Unfortunately, that store is the only place that sells 12.5% and you return the empty bottles and get new ones.

I'll have to try that testing though, I've just been trying to cut down on all the waste with all the bottles and boxes which is why I switched to LC.

[PoolDoc]

Let us know what you find.

(If you get really curious, I can tell you how to directly test bleach % -- but you'll either have to buy some accurate pipettes or a bleach kit.)

[Tom.B]

DANG!!! Just saw this and I had no idea bleach looses its strength! Just went to Wal-Mart over the weekend and about 14 gallons. Now have 17 in the pool shed. So much for BBB saving me money :-( (in jest... kinda) Its only been out there a few days. Can I bring them inside and "save" them? Can I test the strength? Been a cool week so far, but the last batch has been in there for a while. The shed is wood and probably not been in the 90's, however, I can't confirm that.

I was so trying to keep from going for bleach weekly and hoped to go monthly. Bummer.

[Watermom]

Go ahead and bring them in. I buy 8-10 jugs at a time and keep them in my cool basement.

Here are a couple of ways to test the strength of bleach.

The first one was from AnnaK (one of our support team members who is no longer active on the forum.)
* add 10 ml LC to 1 L water, mix,
* add 10 ml of the mix to 1 L water, mix
* test using the 25 ml procedure multiplying the # of drops by 0.2.

------------------------------------------------------------------------------------------------------------------

Here is how CarlD (another one of mods) tests his liquid chlorine:

Put ten liters of tap water ( That's 5 soda-bottles full) in a 5 gallon bucket.

Test that water for chlorine using the FAS-DPD test to get a chlorine baseline (you may have some).

Then I take a 1 ml eyedropper full of the LC or bleach I'm testing and put it in the bucket and mix it up.

(1 ml in 10 liters of water is the same as putting 1 gallon of LC in a 10,000 gallon pool -- it's 1/10,000th. )

I then measure the bucket with the FAS-DPD test just like pool water. Of course, subtract any chlorine you measured in the tap water.

I use a glass eyedropper so it will hold up. Pharmacies sell them.

[amillionpets]

I just read through all of this because I was wanting to know the answer to the initial question as well. Maybe it was in the thread and I missed it? So, should I raise my CYA to keep the FC from dropping so quickly? It seems I am adding a lot more bleach this Summer than last. My CYA is 40. If I raise it to 60 will that help stabilize the FC level a little longer?

[Watermom]

Why don't you try raising it to 50 first before deciding to go to 60. You can always add more CYA but can't remove it. You may find that 50 works better. If not, easy enough to add more.

[PoolDoc]

The best info we have at the moment is that -- generally speaking -- if you run your chlorine at 10% of your CYA level, you will lose about the same chlorine, regardless of levels. Put another way: you'll lose about the same amount of chlorine daily if you maintain FC=3 if your CYA=30, as you will with FC=8 and CYA=80.

However, there is some unconfirmed information that suggests that you will lose less at very high FC/CYA levels (FC=15; CYA=150). But even if that info is correct, the improvement is not huge.

[amillionpets]

Ah! Thank you both very much! That is very interesting, Pool Doc, as I did not know that. So! I guess it's just a bleach adding Summer. That's okay, though, because the water is sparkling clear! Now, if I can just keep the birds from pooping around the rim...............

[PoolDoc]

Now, if I can just keep the birds from pooping around the rim...............

You could try this: