Free Chlorine problem

Hello,

I have had no real problems with my pool til this year. just opened it up 6 days ago and now the water is very clear (normal) and all the reading are
good the ph, alk, etc. the total chlorine is very high and but I keep adding more chlorine but cannot get the free chlorine to register at all on the strips.

I have bought different strips and it also register no free chlorine. any idea ?

I use the frog in-line system to deliver the chlorine and it can be touchy sometimes but it is using tablets, infact in 7 days I have been through 2 1/2
container which when running normal one will last 7 days.

inground fiberglass pool.

Thanks for any help.

Hi, Seadog,

That's an easy one. STRIPS!!! They are notoriously innaccurate and will cause you to chase problems that aren't and overlook ones that are. You need to find a good drops-based test kit so you can have an accurate idea of what you have in your pool. With that Frogger, I'd get one that tests for CTA, as well. It might be quite high.

It will be difficult for anyone to give you any meaningful advice based on the strips. :)

Dave S.

First thing to do is get rid of the test strips (they just won't give you the accuracy you need to maintain your pool) and get a drop based test kit that will test for:
Free Chlorine
Total Chlorine
pH
Total Alkalinity
Calcium Hardness
Cyanuric Acid (Stablilzer or Conditioner)
There are kits available from Taylor and LaMotte that will do nicely.
The best bang for your buck will be the test kit sold on the Poolsolutions website!
http://www.poolsolutions.com/cart/ps234.php
Once you get an ACCURATE set of test results post them on here with your pool size in gallons and the finish (I know you said fiberglass);) and you will get all the help you need with your pool!

Very high levels of chlorine can sometimes bleach out some chlorine tests (depends on the reagent used) I know this can happen with DPD reagent tests, I don't know if the syringaldazine reagent usually used in the test strips is prone to this, if it is it is one possible explanation of your not registering free chlorine. A DPD-FAS titraton test such as in the Taylor K-2006 or the kit sold by Poolsolutions will allow you to accurately test if the chlorine leves are very high.
I notice you mentioned the frog. Is that a PoolFrog? That is an ionizer system that uses (if my memory is right) silver and zinc ions and requires a .5 ppm FC residual. There has been some discussion on this board about them and the general consensus seemed to be to just take them out of the system and use the 3 B's --Bleach, Borax, and Baking Soda. That is what the majority of people on here seem to do and they have very few pool problems:) (and $ave a lot of money in the proce$$!)_

Quote:

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Originally Posted by duraleigh

With that Frogger, I'd get one that tests for CTA, as well. It might be quite high.

Dave S.

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CTA? I've missed that one. What is it?

Prolly a one-finger slip of CYA.

yup, you're prolly right. The reference to tabs slipped right by me!:eek: (I will gladly accept any public humiliation that anyone would like to lay upon me for that one as I humble myself!;))

Ok on the tabs :) , didn't realize that they can cause problems, I am testing with the same brand as always and still no pink at all. is it possible that the chlorine level is so high it will register on the chlorine tab and just bleaching out the free chlorine tab ? can't believe it can be this clear and not have free chlorine. this inline system is called frog and you insert this plastic cylinder that cost like 18.00 and is probably a rip off.

http://www.kingtechnology.com/products/products1.htm

I will get a liquid test kit and check back.

Thanks !!

Quote:

---

Originally Posted by Seadog

Ok on the tabs :) , didn't realize that they can cause problems, I am testing with the same brand as always and still no pink at all. is it possible that the chlorine level is so high it will register on the chlorine tab and just bleaching out the free chlorine tab ? can;t believe it be this clear and not have free chlorine. this inline system is called frog and you instead this plastic cylinder
that cost like 18.00 and is probably a rip off.

http://www.kingtechnology.com/products/products1.htm

I will get a liquid test kit and check back.

Thanks !!

---

Yes that is the ionizer system that I was referring to. You might want to read this thread by PoolDoc (the forum's moderator) about such systems!
http://www.poolforum.com/pf2/showthread.php?t=98
The chlorine tabs are trichlor which contains CYA (stabilzer) and constant use will elevate your stabilzier levels and require that you run higher free chlorine levels and shock levels as the CYA levels increase. This is why most of the people on this forum use bleach which is unstablized chlorine after adjusting their CYA to the level they want. For more info check out this thread!
http://www.poolforum.com/pf2/showthread.php?t=365

As I stated previously, certain Free Clorine tests can bleach out with high levels of chlorine in the water. An FAS-DPD test is the only way to accuately measure free chlorine levels above about 10 ppm that is generally available to pool owners.
Hope this info is helpful to you! :)

Me again, I had my water testing at a pool place with a liquid test kit and they said my problem is my TDS is 3500 ppm and should be 1500 and that I
should replace some of the water til it is down to 1500 or lower, but my water is still crystal clear and the ph, alk, total chlorine is ok, just still no
free chlorine ?

Then I talked to the place that installed my pool and they say the TDS
is not high ?

I guess I'm having trouble understanding what the problem is....you said you have clear water, and your other parameters except for free chlorine are "ok". Could you please post some numbers from a drop-based kit test for TC, CC, pH, Alk, and CYA?
I think your water is probably fine, and that you were probably just bleaching out the test strips. HOwever, without numbers to look at, we're all just guessing.

Janet

tds: 3500
cya: 25
tot chlorine: 10
free Chlorine: 0 <===== the problem :)
ph: 7.6
tot alkalinity: 327
adj. total Alkalinity: 319
tot hardness: 356

Those results look REALLY suspect to me, like they were generated by a computer reading a test strip. They really don't make much sense. I don't know of any drops-based test that measures down to individual units for alk and Ca. I'd go have your water tested elsewhere. Basically it's telling you have CC of 10 which is really, really high. Seeing alkalinity and Ca matching up so close is kinda weird too. It's easy to solve the CC problem though, just dump in bleach to bring your Cl up to 15 or so and hold it there until the CC reads down to 0.

Michael

I would suggest you get a good drop based test kit and test your own water. It is possible that the pool store is making an error in the testing. (ya' think?:rolleyes:) According to Talor Technolgies who manufacture one of the better drop based test kits chlorine levels > approx. 10 ppm can "bleach out" a DPD test for chlorine! You might want to try a different pool store and compare the results. Or ask your pool store to do a dilution on the sample before they test for this reason if they are using DPD. Does your water have a strong "chlorine smell"? This would be an indication that there is combined chlorine in your pool. With no FC and 10 ppm CC (CC=TC-FC) it would mean that all the chlorine in your pool is combined.

Also, do you use a non-chlorine shock? Monopersulfate can also cause interference with DPD testing and show an elevated level of Total Chlorine!
If this is the case it is possible that your chlorine levels are very low and only the shock is showing up on the testing. Taylor Technologies also sells a reagent to help remove this interference.

IMHO, the 2 most probabable scenarios are: either you have very high chorine levels and the type of testing being done is giving inaccurate results because the pool store is using DPD and not FAS-DPD testing (or diluting the sample and DPD testing) and it is bleaching out
or you have an incredible chlorine demand problem and all your chlorine is converting to combined chlorine and you need to shock.

Until you determine which it is you really can't know what you need to do.
Since you just opend the pool it is possible that the chlorine demand is high right now.

Test strips that use syringaldazine reagent supposedly don't "bleach out" (don't know if this is acutally true but that is what is said about them) so if test strips are showing no FC it is possible that the chlorine demand is high

Sorry I can't give you a more definative answer but without GOOD test results from a PROPERLY DONE drop based test it is next to impossible.

thanks, I watched them test it and it was some sort of machine that they put the water into, wasn't a test strip. no strong chlorine smell.

Thanks for all your help.

Yeah, then those results are junk. Get it retested somewhere that actually uses test reagents.

Michael

There are two ways to use strips:

1a) Dip the strip and look at the FC/Free Chlorine side. If it's white, I
have a problem. If it's deep purple, I'm probablly OK. Anything in
between I test with something ELSE that's more accurate.
b) Ignore ALL the other tests on the strip--they are totally worthless
because they are extremely inaccurate.

2) Don't use test strips.