Unexpected High Use of Liquid Chlorine Bleach!!

[1critter]

I just started posting and really paying attention to the balance of my water about a week ago in hopes of better water quality, but I have used alot of liquid chlorine bleach in the past 5 days!! As of today (the 5th day) I have used six 182oz bottles of 6% Clorox and I need to find out if this is normal. I have been running a few 3" Trichlor pucks as well just to keep from getting to 0 FC levels.

It's starting to get a bit frustrating since I have spent roughly $16 on bleach in only 5 days, at this point it will run me roughly $64 a month just in Chlorine.....seemed cheaper when I was running pucks and weekly shocks last year.

For my own water tests I do not have the TFT yet but rely on a pool store purchased kit that will only measure up to 5 for FC. If I'm not keeping my FC at the suggested level for my stabilizer will that cause higher chlorine usage?

I will post my pool numbers below to give you an idea of what the pool has been doing but let me say that the pool looks absolutley fabulous with crystal clear waters and no visibale algea but I'm stumped with the high usage of Chlorine. Thanks for any help y'all can provide :-D


April 29th (pool store test)
FC: 2.0ppm
TC: 2.0ppm
CC: 0.0ppm
PH: 7.0
CH: 325ppm
TA: 75ppm
CYA: 80ppm

May 1st after about a 1/3 water change (pool store test)
FC: 0.2ppm
TC: 0.2ppm
CC: 0.0ppm
PH: 7.6
CH: 250ppm
TA: 100ppm
CYA: 60ppm

May 6th (my test figures)
FC: 2ppm
TC: 2ppm
CC: 0ppm
PH: 7.5 - 7.6
CH: not tested
TA: 90ppm
CYA: 50 - 60ppm
Overnight FC Loss: .5 - 1ppm

 

[JohnT]

If you'll notice at the Chlorine CYA Chart
, you are running very low chlorine levels for your CYA level. Although you are only losing 0.5-1.0ppm overnight, that's around half your total chlorine level, which tells me something is using your chlorine. Try operating in the 5-7ppm recommended in the chart. You might also want to go to shock level to kill off anything that might have gotten established while your chlorine has been low.

 

[257WbyMag]

If you haven't kept records before, it may be a good idea to start doing it when it comes to your pool test numbers. I started doing it when I first began caring for my pool and you can learn quite a bit about your pool's tendencies to use chlorine and varying changes in acid demand, etc. Oftentimes, you can identify problems from subtle changes in water balance and correct something early before it becomes a big problem. Relying on previous year numbers, I discovered about a month ago that I was using way more FC than I had in the previous April and this made me suspicious. I did an overnight FC loss test and realized that I had to shock. Had I not had those records, I probably would have kept feeding my pool's FC and not thought a second thing about it.

I would do what John says and do an overnight FC loss test to see where things come out.

 

[1critter]

Thanks for the tips guys.....I gues until I am able to get a test kit that measure FC in the higher ppm ranges it will be a guessing game since my current "at home" test kit only goes to 5ppm.
Is there anyway for me to pool my FC to shock level without really having a way to measure it?

 

[257WbyMag]

Without being able to measure it with a proper test, you can never know where you truly stand. The FAS-DPD chlorine test is the only test that will allow you to know your FC and CC at levels above 5 ppm. You can purchase a TF test kit with this test in it. See the TF Test Kits link in my signature line.

 

[1critter]

I've been planning on getting the TF test kit that you talk about but I need to wait just a bit to budget it in. In the mean time instead of dumping a bunch of chlorine in to shock which I'm assuming at my current level would be quite a bit of chlorine wouldn't it be cheaper for me to by a couple bags of granulated shock instead?

 

[PaulR]

In general, bleach works out to be cheapest, but you can figure out the relative prices for your own pool.
The pool calculator tells me in your pool, 1 lb of 65% cal-hypo raises FC by about 4; one 182-oz jug of 6% bleach raises FC about 4.5. Which of those is cheaper? (you need to work out what kind of granulated chlorine you have available near you; it varies.) Then remember that granulated always adds something you might or might not want (cal-hypo adds to CH; dichlor adds to CYA).
--paulr

 

[1critter]

In general, bleach works out to be cheapest, but you can figure out the relative prices for your own pool.
The pool calculator tells me in your pool, 1 lb of 65% cal-hypo raises FC by about 4; one 182-oz jug of 6% bleach raises FC about 4.5. Which of those is cheaper? (you need to work out what kind of granulated chlorine you have available near you; it varies.) Then remember that granulated always adds something you might or might not want (cal-hypo adds to CH; dichlor adds to CYA).
--paulr

Hmmmm.....Thanks for the insight Paul, I'll look into it

 

[anonapersona]

And if you use Cal-Hypo, it comes in different strengths and gets much much cheaper in the larger sizes. It keeps well and so it is OK to buy a 50# or 100# buckets. It will add to CH, slowly, but is very nice for shocking since you can add it so quickly and no jugs to deal with. I just got 100# of 73% for about $180 before tax at Warehouse Pool Supply, so that is $1.80/lb. Compare that to $2.54/ 182 oz bleach at Walmart (IF it is in stock!) and the different can buy you a full TFP100 test kit.

 

[JasonLion]

That is a really good price on cal-hypo!

100 lbs of cal-hypo will also raise the CH level of a 20,000 gallon pool by 300, which may or may not be something you want to have happen.