HELP. After months of Trouble Free Pool using liquid chlorine, suddenly NO CHLORINE in pool no matter what I do.

[k.alexander]

Please help me out. First year pool owner. I switched to Trouble Free Pool way of doing things earlier in the summer. Everything has been going great. I've been adding 10% liquid chlorine every day or two and the pool has looked great and my numbers were all good as well.

Suddenly about a week/week and a half ago, when I measure the FAC and TAC, it would show me 0-0.5 for each. No matter how much liquid chlorine I would add to the pool, if I check the water in a few hours, or if I add in the evening and check again in the morning, I'm back to 0-0.5 FAC and TAC. I went through a ton of liquid chlorine bottles all of a sudden, and nothing. Thought that maybe the liquid chlorine I had had gone bad/expired (although it had recent manufacturer dates), so I bought new liquid chlorine (the stuff from Walmart) in fact bought it from three different stores, with again different and very recent manufacturer dates. Again, no change. I put the chlorine in the pool, and if I measure right away (after a few minutes, as I did once -- there is chlorine in the pool), but I come back a few hours later and it's gone. I then went to Leslie's and bought their 5 Gal Jug of 12.5% liquid chlorine, and again, same result.

I even cleaned my filter again last Friday, admittedly the pressure was up and it needed a backwash, but I opened the whole thing and cleaned it with a hose. Then re-added DE. Everything is relatively fine, although I have been fighting some mild yellow algae (just brushing the walls and floor of pool every day or so for the last week when this all started -- obviously with effectively 0 chlorine in the pool).

I had the water tested at Leslie's just yesterday, numbers:
FAC: 0 (this matches my own testing)
TAC: 0 (this matches my own testing)
CH: 300
CYA: 60 (this matches my own testing)
TA: 90
pH: 7.0 (I measure it at roughly 7.2)
Copper: 0
Iron: 0
Total Dissolved Solids: 1100
Phosphates: 0

Can someone tell me what is going on, because I'm about to switch back to tabs and powder shock.
Thanks in advance.

 

[mguzzy]

I take it you don't have an SWG, because that is a good CYA level if you have a SWG. Otherwise you are running high. See here: FC/CYA Levels. Pucks (depending on the type) will make your CYA higher and your FC less effective. Usually sudden unexplained FC loss is an indication of the start of a algae bloom. The best way to test that is a Overnight Chlorine Loss Test

If you are getting a lot of rain this year, you can lower your CYA level through that water dilution.. otherwise you should do a partial drain and refill to get your CYA down.

Where in Philly are you? just curious

 

[Bama Rambler]

Test the pool water and add enough bleach to get it to SLAM level for 60 ppm CYA (24ppm FC) and then wait 15 minutes and test the FC again. Report back what you find.

 

[Mr Bruce]

I'd add and test a lot sooner than every couple of hours at first. Like every 10-15 minutes. And add enough to get to SLAM, not just one bottle or whatever.

 

[k.alexander]

Yes, correct, I do not have an SWG. I would perform the Overnight Chlorine Loss Test, but first I've gotta get my chlorine above 3ppm and I can't seem to do that. Do I just dump a ton and ton of liquid chlorine in there to get to 3ppm or more? Any suggestions? Thanks.

PS: Lived in Center City for the last fifteen years, recently moved to Montgomery County but still close to the city.

 

[Mr Bruce]

Use the pool calculator to see how much bleach will get you to 24. You never "just dump" a bunch of anything in your pool

 

[k.alexander]

Test the pool water and add enough bleach to get it to SLAM level for 60 ppm CYA (24ppm FC) and then wait 15 minutes and test the FC again. Report back what you find.

I'd add and test a lot sooner than every couple of hours at first. Like every 10-15 minutes. And add enough to get to SLAM, not just one bottle or whatever.

Ok, will follow your advice. Thank you. Will add a ton of chlorine and test every 10-15min. What am I looking for at that point?

 

[Bama Rambler]

Just do it once and report back. You're looking to see if the FC immediately goes to zero or if it takes a little while.

 

[Donldson]

Be sure to also test your CC.

And stay out of Leslie's. Nothing good comes from taking your water there.

EDIT: Oh, what you are looking for is to see just how quickly your FC is being consumed. If it's being consumed insanely quickly then the CC test outcome will help direct us towards a likely culprit.

 

[mguzzy]

Yess,.. the chem gurus have chimed in... they know more about SLAMS and FC loss on non SWG pools than I ever will.

My Dad was from Philly, my aunt still lives in the city.. I've spent a lot to time there as a kid. Ya, just can't get a decent cheesesteak west of the Schuylkill my dad used to say, and pretzels were never the same since the Federal burned down.

 

[JoeSelf]

Use PoolMath to see how much chlorine to get to slam level.

 

[thefloatqueen]

I use Di-chlor instead of liquid bleach (chlorine). If my levels are low, that stuff brings it back up FAST lol

Edit: this has nothing to do with SLAM. It’s just what I use daily instead of liquid bleach.

 

[Donldson]

I use Di-chlor instead of liquid bleach (chlorine). If my levels are low, that stuff brings it back up FAST lol

You are aware that dichlor adds virtually as much CYA as it does chlorine, yes? For someone with a CYA of 60 aiming for 24 FC that would also raise the CYA up 22 ppm. That's hardly putting OP in a better position. Not to mention the advice is just wrong anyway: chlorine is chlorine and once dissolved in to the water no source raises it faster than any other.

EDIT: Wait, you use dichlor for daily chlorination? That's a terrible idea. Might as well use trichlor tablets, your CYA won't skyrocket quite as quickly...

 

[thefloatqueen]

You are aware that dichlor adds virtually as much CYA as it does chlorine, yes? For someone with a CYA of 60 aiming for 24 FC that would also raise the CYA up 22 ppm. That's hardly putting OP in a better position. Not to mention the advice is just wrong anyway: chlorine is chlorine and once dissolved in to the water no source raises it faster than any other.

I’m going off prior experience but the bleach I used was 6%. I am aware both are chlorine lol. I mentioned Dichlor because at the end of his post, he contemplated switching back to powder and/or tabs. Only reason I mentioned it. ??‍

 

[k.alexander]

Ok gang, update. Added the correct amount of liquid chlorine just now to get me up to 24ppm. Turned the pump on to help circulate. Took measurements about 20 min later (this is just about 10 min ago).
FAC: ~19
CC: 0-0.5

It’s about 10:30pm here. What should I do next? Keep taking measurements every half hour or so for the next few hours? Then see what the measurements are in the early morning? What am I looking for? Am I basically doing the Overnight Chlorine Loss Test at this point?

Thanks!

 

[frogabog]

20 minutes =5ppm FC loss?

I can't see any reason to do an OCLT at that point. Plus it's after dark anyway, you clearly lost over 1ppm "overnight" even if overnight hasn't happened yet. You need to SLAM. That means, testing and adding chlorine to get back to 24ppm as often as you can.

 

[k.alexander]

Ok, so update.
So last night I added enough liq chlorine to get to 24ppm.
20 min later I was down 5ppm of FC, down to 19ppm.
1hr-1hr and 15min after the initial chlorination I was down another 5ppm, now down to 14ppm.
At that point I added enough liq chlorine to get me back to 24ppm -- this is about 11:30pm last night.
7am this morning, did a test which showed: FC 11.5, CC: 0-0.5; TC: 11.5
I then added more liq chlorine but I only had enough left to get me up to about 17ppm.

My questions are as follows:
SLAM Process says, keep doing SLAM until: 1) Clean Water, 2) Pass the OCLT, 3) CC is less than 0.5. I have clean water (criteria 1), and my CC is and has been less than 0.5 (criteria 3). I am clearly not meeting criteria 2 as I continue to drop significant amounts of chlorine, be it overnight or whenever. So, do I continue with SLAM until I Pass the OCLT (criteria 2)? Why is that important? And really what I want to know is why am I losing so much chlorine overnight, so quickly? How much, if any chlorine should I be loosing overnight when everything is fine? How much chlorine should I be loosing during the day in the summer? And lastly, how much liquid chlorine are you guys adding on a daily basis when everything else is ok?

Really appreciate the help from everyone. Thanks again!

 

[mknauss]

So, do I continue with SLAM until I Pass the OCLT (criteria 2)?

Yes

Why is that important?

Less than 1 ppm FC loss overnight shows there are no organics in the pool the chlorine is reacting with.

And really what I want to know is why am I losing so much chlorine overnight, so quickly?

There are organics somewhere in the pool water system.

How much, if any chlorine should I be loosing overnight when everything is fine?

Less than 1 ppm FC

How much chlorine should I be loosing during the day in the summer?

Typically 2-4 ppm FC during the day.

And lastly, how much liquid chlorine are you guys adding on a daily basis when everything else is ok?

2-4 ppm FC

 

[k.alexander]

THANK YOU! AND AGAIN THANK YOU! So few people will take the time and answer every question asked, directly. Thank you!
One follow up comment and question that I neglected to mention above. I brushed the pool last night and this morning. Couldn't see much last night, but this morning, first the pool looked clean in that there weren't collections of dead algae, you know the stuff that looks like little piles of sand anywhere in the pool; and second, when I was brushing this morning, there was very minimal algae that I could see coming off the walls. So does that mean that I don't so much have algae problem but rather some other organics/contaminants in the water and that's what I'm trying to get rid of with the SLAM process?

 

[mguzzy]

And lastly, how much liquid chlorine are you guys adding on a daily basis when everything else is ok?

So.. your probably looking for an answer in terms of volume.. (this many cups, 1/2 a gallon, etc)... well we'all talk in terms of ppm because we don't know how big your pool is. (Well I suppose we do in your signature, but we are all a lazy lot, and we'll let you do the calculation)., So use the PoolMath app to calculate how much CL to add for you volume of pool.