Chlorine eating through liner ?

[sbelgrave]

Hey guys,

So we've been using BBB for a number of years now and it's been great. However, we have a vinyl liner out of ground pool and the new liner was just installed like 2 years ago. Today, i'm seeing what i'm sure is a leak right at the bottom of the pool (sand run off) where i usually put the chrorine (chlorox) in right at the base of the return. Considering no one has been the in pool at all recently the only logical conclusion I can come to (assuming there is a indeed a leak) is that this is a direct result of pouring in the chlorox too fast and maybe extra amount of chlorine touch the bottom of the pool and eat away at the liner? anyone agree/disagree with this. Any other possibilities. At 6:00pm tonight i measured the drops of water i could see where the sand runoff is and it's about 86 drops per minute. Also, in the case where people do this (have their liners eaten away by chlorine) at the base of the return...is it actually worse than a specific hole in the liner because the damage is so spread out. Can people patch these things well or is it likely to be a money pit vs. getting a new liner. ugh. help. Thanks

Scott

 

[Donldson]

I don't know if it's possible, but a couple pertinent questions are what is your CYA, your pH, and what FC do you maintain? Do you also pour muriatic acid there as well? And finally, I hope a stupid question here but I hate to make assumptions, is your pump running when you add chlorine?

 

[sbelgrave]

haha (the pool pump on assumption ). Totally good questions and thanks for asking them. Yes, the pool pump is on when i pour it in but as for the level, lemme go check on them now. I can't promise that they'll be optimal as I haven't checked them a good while since the pool has been clear and the kids haven't really gone in but if it's indeed somehow a factor, i'm all ears and willing to find out. Be back soon.

Scott

 

[sbelgrave]

Yikes. Ok. so here's the levels. (We're currently shocking it today (got back from long vacation this past week) so i can't remember if that makes the readings all over the place or not)

PH. 8.0+
AK : 70
CYA : 10 (the hose slipped off the return earlier this week and drained the pool a lot so , since then been filling with new water so i'm sure the cya's been diluted obviously)
CH : 13ppm (currently shocking it, which is pretty much the reason i even noticed the leak in the first place since it's right where i go to pour it in)

From your post earlier you also asked if i used Muriatic Acid i believe. No, we don't.

So lets say these readings above our correct.
1) Would they be able to harm my pool in any way or allow the chlorine to eat away at it faster or something. Not sure if that's where you were going with your questions.
2) And again, if anyone else is reading this, is trying to patch a liner that has been eaten away by chlorine a crazy idea, is it harder to do since the overall area is larger than specific tear or hole ? Thanks again everyone.

Thanks,

Scott

 

[Bama Rambler]

The chance of it being the chlorine eating the liner is pretty nil. Even if you poured it right onto the liner without the pump running it would take many many years for it to eat through the liner, and I'm not sure it ever would.

As for patching it. That shouldn't be a problem. You can patch some pretty big spots. Whatever caused it.

 

[y_not]

You said you're currently SLAMing your pool, so it should be @ shock levels. However you don't list your CL levels.
It's almost impossible to SLAM a pool /w such low CYA, the sun just eats it up much too fast.
I presume you have a sock containing enough CYA to bring you up to 30-50ppm, hanging by your return? Better to be on the safe side and bring it up to 30ppm, since:
A. You have to shock, so less CL use.
B. You don't want to overshoot it, as anything less than 20ppm on the TF100 CYA tube is just a guess. You don't know where you are.
Remember, CYA is easy in, drain to get out.

When testing CYA, make sure you do it outdoors, in the daylight, with your back to the sun & the test tube @ waist level. Don't even bother doing it indoors, you'll get a false reading. Typically very low. Its accuracy is about +/- 15ppm to begin with.

As for the use of MA, it's used to bring down pH as it naturally rises up. What then are you using to lower your pH when it goes up? Dry Acid? Or are you not checking & correcting your pH?
Keep in mind that pH readings when FC is above 10ppm are false and unreliable. You shouldn't test for pH /w FC that high when @ shock levels, if you do, ignore it.

Your TA seems fine to me. However, your CH, how did you arrive @ 13ppm?
TA is read in multiples of 10, the lowest number above zero that you can get is 10ppm, the next step up is 20ppm.
Please read the extended test kit directions, specifically the TA section here: extended-test-kit-directions-t25081.html#p206395

How deep is the pool @ the return jet that your pour bleach in front of?

Lastly, we need to know your pool stats....
Please fill out your signature with this information, as well as your location info in your profile as instructed in the 1st link in pool school. This way we can better assist you based on your climate and equipment.

 

[y_not]

The chance of it being the chlorine eating the liner is pretty nil. Even if you poured it right onto the liner without the pump running it would take many many years for it to eat through the liner, and I'm not sure it ever would.

As for patching it. That shouldn't be a problem. You can patch some pretty big spots. Whatever caused it.

I'll add to that with this.
You should see a "bleached" spot, or discoloration at the suspect location if this were the case.
Do you? Can you provide photos?

Also, I would get down there asap, find the hole & patch it. Losing water messes up your chemistry & costs you money. Both in re-agents from testing it more than necessary, chemicals and not to mention time & energy. Plus, the more your sand bed erodes, the more costly, time consuming and frustrating it is going to be to fix it.

Lastly, I have never seen anyone on here with a leaky liner as a result of bleach additions to the pool eating the liner. Acid, yes, not even that often though. Usually it all just bleaches the liner and that's that. Looks ugly, but doesn't leak.

 

[chem geek]

Do you add acid in the same spot? If so, it's more likely to be pooling of acid. Low pH is far worse to vinyl liners than chlorine. That's why we recommend lightly brushing the side and bottom of the pool where you add a concentrated chemical, most especially when adding acid, though it wouldn't hurt when adding chlorine if one tends to add it too quickly.

 

[sbelgrave]

Thanks to both of you for the responses. I really appreciate it.

@y_not. Lemme try and answer all of your questions here.

- Yeah, we're trying to get the CYA back up now (sock) as the sun's gonna kill it all quick otherwise.
- For lowering the PH I've used some stuff called 'PH Down' that I had from years ago. (i think i've used it like twice in 5 years as the PH has not been problematic before)
- The CH level was cuz i had halved the equation for measuring it in the Taylor Test Kit (instead of 1 drop equalizng .5ppm, i'd been filling the water to 5mL and then doing 1ppm for every 1 drop if that makes sense. And PLEASE correct me if that is not ok. I had just noticed that on the kit itself that it had in fact done the same thing by using two examples. Will totally change that if i'm wrong)
- As for TA, yeah, it's 70ppm, i think i wrote 'AK' for some reason. sorry.
- As for my signature, are you guys not seeing the stats at the bottom ? it should read something like, "westminster, md....16x32x4 oval , 10000 gallons, vinyl non-saltwater"....i see it on my screen here...but apologies if its not showing up for the rest of you.

Thank you again.

Scott

 

[woodyp]

Can we get you to edit your signature down to 5 lines or less per forum rules?

 

[sbelgrave]

@woodyp.

Sure thing. Done.

Scott

 

[chem geek]

Yes, when using a 5 ml sample size for the FAS-DPD chlorine test then 1 drop represents 1 ppm.

 

[y_not]

Yes, when using a 5 ml sample size for the FAS-DPD chlorine test then 1 drop represents 1 ppm.

He's doing this on the CH test. I thought you could only go down to a 10ml sample for very high CH. Which does sacrifice accuracy, but saves on re-agent and time. Which when it's into the region of, say... 500+ WHO CARES!! LOLs

Wouldn't you have to go up, way way up in sample size to get that kind of accuracy on the CH test? IE. 1ppm : drop.
Not to mention a whole BOATLOAD of re-agent!!

Thanks to both of you for the responses. I really appreciate it.

@y_not. Lemme try and answer all of your questions here.

- Yeah, we're trying to get the CYA back up now (sock) as the sun's gonna kill it all quick otherwise.

Good good, good show!

- For lowering the PH I've used some stuff called 'PH Down' that I had from years ago. (i think i've used it like twice in 5 years as the PH has not been problematic before)

Where does your pH like to hover? Where & how are you adding the dry acid to the pool? Sounds like you have eeextremely soft water.

- As for TA, yeah, it's 70ppm, i think i wrote 'AK' for some reason. sorry.

Silly TYPOS!!
Get ya' every time.

- As for my signature, are you guys not seeing the stats at the bottom ? it should read something like, "westminster, md....16x32x4 oval , 10000 gallons, vinyl non-saltwater"....i see it on my screen here...but apologies if its not showing up for the rest of you.

Aaahhh, I saw your sig at 1st, but then when I looked again I totally missed it. It just bleeeended into your post, what /w the HTML typical <> formatting symbols, as opposed to the PHP BBB forum SW's [] symbols. Those have caught me before as well, seeing as I know HTML... mostly.
Tip: You can gain an extra line for other stuff by putting your location in your profile.
User Control Panel>Profile>Edit Profile.

Thank you again.
Scott

Sure man, thank you!

EDIT: sbelgrave, I still don't know what your FC ppm level is, nor your CYA target. Please advise.... thanks.

 

[chem geek]

He's doing this on the CH test. I thought you could only go down to a 10ml sample for very high CH. Which does sacrifice accuracy, but saves on re-agent and time. Which when it's into the region of, say... 500+ WHO CARES!! LOLs

You are right that with the CH test the 25 ml sample is 1 drop = 10 ppm while the 10 ml sample is 1 drop = 25 ppm and a 5 ml sample would be 1 drop = 50 ppm.

 

[y_not]

You are right that with the CH test the 25 ml sample is 1 drop = 10 ppm while the 10 ml sample is 1 drop = 25 ppm and a 5 ml sample would be 1 drop = 50 ppm.

So his CH is actually 650ppm then, huh?

 

[chem geek]

Yes, if it was 13 drops in a 5 ml sample with the CH test, then it would be 650 ppm, but all the reagents would need to be scaled for a 5 ml sample size and that may not have been done so the test might not be that accurate. There's really no reason to use anything smaller than a 10 ml sample size for the CH test unless one expects CH to be up closer to 1000 ppm or something like that.