Can't get measurable CL with tabs and floating chlorinator

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G

goofiness

Bronze Supporter
LifeTime Supporter
Jul 3, 2011
87
Stockton, CA
Pool Size
21000
Surface
Plaster
Chlorine
Liquid Chlorine
Pool 22,500 gal, plaster, solar heat, temp 86. CYA: 100. pH 7.5. Typical CL levels: FC: 1.0, CC: 0.5. Last replaced about 1/2 pool water 2 years ago. We have well water, which is hard.

I used floater with 3"tabs for years, but gave up because the only way to find chlorine in the water was to take the sample from INSIDE the float. My neighbor uses a double chlorinator, which I went out and bought. Result after 24 hrs: FC: 0.5!
I am adding chlorine twice a day: liquid 10%, dichlor or Ca hypo just to maintain decent levels. I typically have FC 1ppm, CC 0.5 PPM. I have shocked with all kinds of powders, as well as Leslie's Fresh N' Clear. The water is crystal clear, there are a couple streaks of green on the tile grout near the skimmer inlet, but no slime and otherwise looks fine.

Help! This twice a day chlorinating is driving me nuts.
 
Re: Can't get measurable CL with tabs and floating chlorinat

Welcome to TFP!

Odds are, you have something in the water that is consuming your chlorine about as fast as you are able to add it. And those tabblets can't keep up witht he demand either.

Your CYA is at least 100 and this is too high. Do you realize that in order for you to have clean water, your FC needs to be a minimum of 7? You need to stop using tablets as they are adding more CYA that you don't need. You are also going to need to change out some water to get the CYA down to a manageable level, say, 30 to 50.

I would like to suggest that you begin reading Pool School. By doing so, you will begin to understand why your pool water is behaving the way that it is.
 
Re: Can't get measurable CL with tabs and floating chlorinat

Green is not good in a pool. At all.

Your high chlorine demand is probably due to organics. You need to get it high and keep it high because you have high CYA due to pucks. Like, 8 to 13 normally, and all the way up to 25 while shocking. And that doesn't mean up to 25 just once; that may mean adding every couple hours for a few days to keep it at 25 until the shock processis complete. I suggest you spend some time reading Pool School, especialy the how-to article about shocking,
 
Re: Can't get measurable CL with tabs and floating chlorinat

Thanks for the advice. The last time I totally drained the pool for new plaster and tile, I did not add any stabilizer. The CYA has gradually crept up from using diclor. I have used Ca hypo on an alternating basis, but find that it clouds up the water and leaves a residue for 2 days.
I believe that I need to replace some water to get the CYA down. After that, I do not know how to proceed. I see that the preferred method for chlorinating is liquid, but that is cumbersome and requires daily attention. I was hoping there was a more convenient way, but... I suppose the answer will be a SWG.
 
Re: Can't get measurable CL with tabs and floating chlorinat

I would take steps to lower your CYA (partial drain and refill) first. Then, once you have done that, post some test results for us to see that include FC, CC, CYA, pH, TA, and CH. We will guide you from there.
 
Re: Can't get measurable CL with tabs and floating chlorinat

Thanks again. In trying to remember the sequence, I believe I started alternating products last year to try to minimize the side effects of each one (CYA, calcium, cloudiness, etc.). I'll go ahead and drain maybe 1/3 of the water, which I hate to do because it wastes water and costs $$$. Perhaps the answer is to stop using any stabilized chlorine products. In California, we've got lots of water this year; some years we have barely enough, so this CYA is a big issue.
 
Re: Can't get measurable CL with tabs and floating chlorinat

You may want to look into RO water treatment. Costly, but saves the water, and the RO company will properly balance the pool when they are done.
 
Re: Can't get measurable CL with tabs and floating chlorinat

Yikes! One more query. If I the pool water is clear, and I have virtually no measurable CC (0.5 ppm), do I need to superchlorinate? If so, do I try to get a FC value based on "The Calculator", or just bring it up to 10 ppm?

Thanks, again.
 
Re: Can't get measurable CL with tabs and floating chlorinat

goofiness said:
Yikes! One more query. If I the pool water is clear, and I have virtually no measurable CC (0.5 ppm), do I need to superchlorinate? If so, do I try to get a FC value based on "The Calculator", or just bring it up to 10 ppm?

Thanks, again.
Click to expand...
Your first post said that your CYA is 100, but we know that most CYA tests can only test up to 100 and show any CYA level 100 and over as 100 :shock:
So, it could be 200 :shock: just don't know.

As Anonapersona mentioned RO, I also suggest you see if RO is available in your area.
Being on well water, the RO could be extra beneficial to you.

It sounds like your pool is too overstabilized for you to be able to maintain any safe level of chlorination. Sorry to sound negative, but I don't think that 'superchlorinating' or raising FC to 10 is going to do much.

You have, however, come to the right place to learn about your pool! Welcome to the forum :wave:
 

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Re: Can't get measurable CL with tabs and floating chlorinat

The CYA test I use is the one with the black dot in the bottom of the tube. Is has gone progressively up, so I guess I don't know for sure whether it is above or below 100. Last time I had it checked at Leslie's, perhaps a month ago, I believe they reported under 100.

But, I don't ever recall learning about the adverse impact of CYA on chlorination, other than at sites like this one. Neither the retailers or product literature ever advises that high CYA levels will make it difficult to use chlorine effectively. It only cautions that a level >150 indicates water change is needed.

This will be pretty dumb, but I thought RO in a household was to remove unpleasant stuff from small volumes of water for drinking and cooking. How does RO help with my CYA/chlorine issues in the pool? Thanks.
 
Re: Can't get measurable CL with tabs and floating chlorinat

goofiness said:
The CYA test I use is the one with the black dot in the bottom of the tube. Is has gone progressively up, so I guess I don't know for sure whether it is above or below 100. Last time I had it checked at Leslie's, perhaps a month ago, I believe they reported under 100.

But, I don't ever recall learning about the adverse impact of CYA on chlorination, other than at sites like this one. Neither the retailers or product literature ever advises that high CYA levels will make it difficult to use chlorine effectively. It only cautions that a level >150 indicates water change is needed.

This will be pretty dumb, but I thought RO in a household was to remove unpleasant stuff from small volumes of water for drinking and cooking. How does RO help with my CYA/chlorine issues in the pool? Thanks.
Click to expand...
This is a big trailer-mounted unit that sucks the water out of your pool, removes virtually everything, and returns essentially distilled water to the pool. No more high Calcium, no more CYA, no metals.
 
Re: Can't get measurable CL with tabs and floating chlorinat

Aha. Thanks again. We are in Stockton, and I've no idea if there are any operations like that for RO, but I will do some checking. I imagine it is quite expensive.

I put 3 gallons of 10% liquid chlorine in the pool. Two hrs. later: FC: 20, CC: 0.5. That should kill everything, and the level will probably drop below 5 in 24 hrs.

Any insights about SWC??? I just spent $2000 for a Pentair VS pump and Sun Touch controller, and thought I was done with large capital outlays for a while. But this chlorine business is out of control.
 
Re: Can't get measurable CL with tabs and floating chlorinat

Butterfly said:
goofiness said:
Yikes! One more query. If I the pool water is clear, and I have virtually no measurable CC (0.5 ppm), do I need to superchlorinate? If so, do I try to get a FC value based on "The Calculator", or just bring it up to 10 ppm?

Thanks, again.
Click to expand...
Your first post said that your CYA is 100, but we know that most CYA tests can only test up to 100 and show any CYA level 100 and over as 100 :shock:
So, it could be 200 :shock: just don't know.

As Anonapersona mentioned RO, I also suggest you see if RO is available in your area.
Being on well water, the RO could be extra beneficial to you.

It sounds like your pool is too overstabilized for you to be able to maintain any safe level of chlorination. Sorry to sound negative, but I don't think that 'superchlorinating' or raising FC to 10 is going to do much.

You have, however, come to the right place to learn about your pool! Welcome to the forum :wave:
Click to expand...

Here goes. After having trouble getting any chlorine level at all, with CYA>100, I did a partial refill around 60% on 7/10. I got CYA 30-40; pool supply gets 55-60. The water is clear, no visible algae, no dust when I brush, no eye burn, no slime. I've been shocking with liquid to FC 16, based on CYA of 40. But, I am having to add more and more chlorine twice a day, and overnight I am losing more. Last night at 11 PM, FC 17.5; this 8 AM: FC 12.0, CC 0.5.

Now I am going to shock up to FC 24, based on CYA of 60 (?)

Numbers on 7/16:
pH: 7.8
TA: 180
CH: 240
CYA: 40 (my test); 60 pool supply

So, I will try to maintain FC at 24 for a couple days, and see if I still get a large overnight drop.

Any other ideas? Thanks.
 
Re: Can't get measurable CL with tabs and floating chlorinat

A drop of FC from 17.5 at 11 pm to 12.0 at 8 am is an indication of organics in the pool.

A shock level of 24 is correct. I would lower the pH to perhaps 7.4. I would run the pump 24/7 until you kill all the organics. I would brush the side and bottom of the pool once or twice a day.

I have not used an algaecide to clear up algae in years. However, given your level of frustration you could consider a poly algaecide. Not necessary but this might make you feel better.
 
Re: Can't get measurable CL with tabs and floating chlorinat

Steve456 said:
A drop of FC from 17.5 at 11 pm to 12.0 at 8 am is an indication of organics in the pool.

A shock level of 24 is correct. I would lower the pH to perhaps 7.4. I would run the pump 24/7 until you kill all the organics. I would brush the side and bottom of the pool once or twice a day.

I have not used an algaecide to clear up algae in years. However, given your level of frustration you could consider a poly algaecide. Not necessary but this might make you feel better.
Click to expand...

Thanks. I put a bit of acid in. The FC is now 29 after the last dose 2 hrs ago, using the Pool Calculater. I'll test once more tonite, to get a good overnight chlorine test. I really hope this is coming to a conclusion. Lugging those jugs of chlorine is killing my back, which would feel better if I could get in the water!
 
Re: Can't get measurable CL with tabs and floating chlorinat

Brushpup said:
Stick with the bleach/chlorine...stay away from algacide. Hang in there, it will come around. Welcome to TPF BTW!
Click to expand...

Thanks. I had to add more chlorine last night, so did not do the OCLT. But, this AM the FC is 20.0, CC is 0.5. Maybe a glimmer of hope...

Of course, it is still difficult to fathom how this pool can consume so much chlorine in the absence of any visible evidence of algae or any other bad things. I understand that this stuff is microscopic, but no cloudiness, no "dust" with brushing, no nuthin".
 
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