Very Interesting Problem

[F3AFlyer7]

That explains my issue much better! The main test we use is a simple test strip that tests for Calc. Hardness, TC, FC, Alk, pH, and CYA. We usually don't test for TDS, but this is what we were assuming to be the problem, don't really know why as I only have 3 years experience. So would you say the key to preventing this is in the hands of the pool owner to test and shock their pool more often, or would there be another way? I wouldn't be so concerned if it was just an issue with a few customers, but, like I said, this problem exists in almost half our customer base.

We have been telling people with the problem to shock their pool more often, and I guess that's the key after all.

Thanks a ton!!

[duraleigh]

You're welcome....hope that IS the issue...sure sounds like it.

Test more often and accurately....yes, but shock only when needed.

This forum is somewhat centered around the poolowners' capability to test their own water. The originator sells a kit that is the cadillac of the industry. If you are so inclined, send your folks that really want it to poolsolutions.com to order the kit. It sells for 80.00 and tests accurately for TC up to 5ppm, FC up to 50ppm, and CC. It also tests for pH, Alk, Calcium and CYA.

[redger]

Couldn't this problem also be associated with the CYA level being too high? It would be interesting to know what CYA levels these problem pools have. If the CYA is very high, then it will take even more chlorine to reach the shock level.

Your typical pool uses the chlorine pucks in a chlorinator, and the chlorine pucks continue to add to the CYA levels, and eventually it gets too high. That's why most people on this forum avoid using the chlorine pucks when possible.

[waterbear]

Couldn't this problem also be associated with the CYA level being too high? It would be interesting to know what CYA levels these problem pools have. If the CYA is very high, then it will take even more chlorine to reach the shock level.

Your typical pool uses the chlorine pucks in a chlorinator, and the chlorine pucks continue to add to the CYA levels, and eventually it gets too high. That's why most people on this forum avoid using the chlorine pucks when possible.

Very good point! From the amount of chlorine needed to reach breakpoint in these pools I would make a wager that the CYA levels are running high.
1 gal of 12.5% chlorine will raise 1000 gal 10 ppm so these pools are needing LARGE amounts of chlorine to reach breakpoint (12 ppm and up)!

Test strips, although they do give accurate results, do NOT have the precision (resoluton) to base water chemisty adjustments on! For example, how can you ajust pH when all you know is that the pH is somehwere between 7.2 and 7.8 which is what the majority of strips will tell you?

Pools with very high TDS from old water that have been using stabilized chlorine will also have very high CYA levels. The problem is NOT from the high TDS but from the high CYA. Both readings go up when the water is old. If high TDS had an effect then every pool on a SWG would be in trouble since their TDS is going to be higher than their salt reading and well above what is considered to be too high (even in new pools), which is a part of the measured TDS! Obviously, this is not the case.

The accepted cure for high TDS is to drain and refill, exactly the same as for too high a CYA reading! Which is the culprit, TDS or CYA? I put my money on CYA every time!

IF you want to make your customers happy invest in one of the water labs available to the industry from companies like Tayor or LaMotte and stop using the strips so you can accurately diagnose what is going on in their pools!

[duraleigh]

I do not recall seeing high CYA values and cloudy water being closely related on this forum. Not saying they are not, I simply don't recall it.

I DO frequently see cloudy water and CC associated, however.

[waterbear]

no, but if CYA levels are high and FC is not high enough for the CYA then the FC that is there will form CC. Remember, the 'accepted' range for FC is 1 to 3 ppm. If the CYa is at 90 or higher ppm that just isn't enough FC in the water.

[gonefishin]

I do not recall seeing high CYA values and cloudy water being closely related on this forum. Not saying they are not, I simply don't recall it.

I DO frequently see cloudy water and CC associated, however.

This "best guess CYA chart seems to be a handy chart. Trouble with high CYA seems to be that it demands higher minimum chlorine levels be maintained to sanitize the water.

dan

[Bleach=Chlorine?]

Can this be moved to the thread about interesting things you've heard/been told at the pool store? - Just Kidding

[CarlD]

1 gal of 12.5% chlorine will raise 1000 gal 10 ppm so these pools are needing LARGE amounts of chlorine to reach breakpoint (12 ppm and up)!

WHOOPS!!!! This math is all wrong! 1 gallon of 12.5% chlorine will raise 1,000 gallons of water to 125ppm! 'Way, WAY too high. Lost a zero somewhere. It will raise 10,000 gallons to 12.5ppm, rather than 10ppm, assuming, of course, that the 12.5% didn't break down to 10% (which is likely). If it has broken down to 10%, then, of course, it will only add 10ppm, not 12.5

Test strips, although they do give accurate results, do NOT have the precision (resoluton) to base water chemisty adjustments on! For example, how can you ajust pH when all you know is that the pH is somehwere between 7.2 and 7.8 which is what the majority of strips will tell you?

Waterbear is using his language very, very precisely ( ) here. It is extremely easy to get spurious results with most test strips. If you run the test even slightly wrong, or there's the tiniest contamination on the strip, you'll get bad readings.

Pools with very high TDS from old water that have been using stabilized chlorine will also have very high CYA levels. The problem is NOT from the high TDS but from the high CYA. Both readings go up when the water is old. If high TDS had an effect then every pool on a SWG would be in trouble since their TDS is going to be higher than their salt reading and well above what is considered to be too high (even in new pools), which is a part of the measured TDS! Obviously, this is not the case.

The accepted cure for high TDS is to drain and refill, exactly the same as for too high a CYA reading! Which is the culprit, TDS or CYA? I put my money on CYA every time!

IF you want to make your customers happy invest in one of the water labs available to the industry from companies like Tayor or LaMotte and stop using the strips so you can accurately diagnose what is going on in their pools!

Other than that, I sure appreciate Waterbear doing my job so I don't have to!

[waterbear]

WHOOPS!!!! This math is all wrong! 1 gallon of 12.5% chlorine will raise 1,000 gallons of water to 125ppm! 'Way, WAY too high. Lost a zero somewhere. It will raise 10,000 gallons to 12.5ppm, rather than 10ppm, assuming, of course, that the 12.5% didn't break down to 10% (which is likely). If it has broken down to 10%, then, of course, it will only add 10ppm, not 12.5

Math neve was my strong piont. Niether is typoing I dropped a 0! (and I treat 12.5% chlorine as 10% because it probably is by the time it goes in the pool! I was rounding off for simplicity. 100 oz is closer to 3 1/4 qts. (10 oz of 10% will raise 1000 gal 10 ppm) Thanks for catching that, Carl!

My point still holds. These pools are needing HUGH amounts of chlorine to reach breakpoint. 12 to 16 gallons in a 10000 gal pool means 120 or higher ppm chlorine!