use of liquid chlorine in AG vinyl lined pool

[CarlD]

Pool store guys will make up all KINDS of crazy reasons why you shouldn't use bleach but spend a fortune on THEIR chlorine (even Liquid Chlorine 6% which is....bleach). Obviously, it's all about the money.

[Darkside]

i brought home 4 big jugs ( 1.42 gal ) of walmart brand bleach, 4 lbs of borax, and 4 lbs of baking soda. i poured 1.42 gal of bleach in last night and showed around 1.5 FC this morning. i tested today after work and show 0 FC...

ran a set of test's and heres what i got. watermom is correct i have a taylor K2005.

FC 0
TC 1
CC 0
PH under 70 ( appears to be a shade under ) base demand test was 6 drops.
ALK 70
CYA doesnt even go over 100 before the black dot disappears. the level is around half way between the bottom of the tube and 100. i tested CYA a few days back and it was around 70-80 and i have not drained off any water, or added stabilizer ( we have been getting rain ). i did the test twice today just to make sure i didnt mess it up the first time.

my pool is 18ft round AG with a vinyl liner. approx 7,500 gallons. pump is ( i think ) 1.5 HP on low, and 2 HP on high. filter is a waterway proclean 125 sq ft.

my pool is currently blue, but very cloudy since i just killed off a bunch of algae.... my filter is only 1 year old but im wondering if i need a new one?

[Watermom]

TC = FC + CC. Always. With a CYA of 70-80, you need to be shocking up to 20ppm. Adding 4 big jugs would have added 45ppm! Way too much! So, what is really happening in your pool is that you have so much chlorine, that you are probably bleaching out the DPD test and it appears that you have none!

Don't add anymore chlorine at this point. Use a dilution test to see if you can get a better reading. More about that here: Testing Without a Good Kit

Your pH test will be inaccurate with high chlorine. But, typically with high chlorine, you get a falsely high pH. So, I'm going to suggest going ahead and adding a half a box of Borax slowly to the skimmer while the pump is running.

You do not need a new filter, but your pump is WAY oversized for your small pool. We see this a lot. When a pump is too big, it forces stuff through the sand bed without filter it out well. Thus, it can take a long time to clear a pool.

Repost with the dilution test results. Also, if you can, order that K-1515 add-on kit I mentioned above.

[Darkside]

i had a CYA of 70-80 a few days ago, but today i dont even reach 100 before the black dot goes away. i didnt add all 4 jugs of bleach last night, just 1 jug. i will try the dilution test tomorrow after work. my pool doesnt have a strong chlorine odor at this time, actually very little chlorine odor. i will order the K-1515 tonight. my filter doesnt use sand its just a plain old cartridge filter. i was talking with my wife and the filter is actually two years old... oops. i never had a cloudy water problem before, so im going to order a new filter tonight just to rule that out. ill keep my current filter as a back up.

thanks for the help!

[Watermom]

Then, your CYA is over 100. Try the dilution test on this one, too, to try and see if you can't get a little closer reading. Dilution isn't super accurate, but better than nothing.
Why is your CYA climbing? Have you added some recently and if so, when and how much? Or are you using a stabilized form of chlorine such as trichlor tabs or dichlor shock powder?

Glad to hear you didn't add all that chlorine at once!

[Darkside]

i was able to do the chlorine dilution test and the color was a very light pink color. i used 1 part tap water and 1 part pool water and 5 drops each of R-001 and R-002.

Then, your CYA is over 100. Try the dilution test on this one, too, to try and see if you can't get a little closer reading. Dilution isn't super accurate, but better than nothing.
Why is your CYA climbing? Have you added some recently and if so, when and how much? Or are you using a stabilized form of chlorine such as trichlor tabs or dichlor shock powder?

Glad to hear you didn't add all that chlorine at once!

i was using both trichlor tabs and dichlor shock but have stopped using them. i will try the dillution CYA test and post back. i will need to get more R-0013 since i only have one bottle left.

i just ordered the K-1515 and a new filter, thanks again for the help!

[BigDave]

I'm concerned that you have no chlorine in your pool and you're in another algae fight. I'm sorry to disagree with you watermom.

If you read this before leaving work, please pick up a cheap OTO/pH test kit on your way home. It wil definitively tell you if you have lots or no chlorine; OTO doesn't bleach out. If your wall mart has the HTH 6-way kit (check availability), get that, it will supplement your K-2006 and give you an OTO kit as well.

If you have no FC, you need to get to shock level (25ppm+) and keep it there until you have less tham 1ppm loss of FC overnight and 0.5ppm or less CC.
Two big jugs (1.42gal) of 6% bleach should get you near 25ppm.