Commercial pool sanitizing methods?

[DLSDO]

Do large commercial pools (hotels, clubs, residential community pools) use some kind of automated chlorinators for santization? Do they use liquid chlorine or trichlor? If they use trichlor do they have to empty and refill often due to high CYA levels?

Also.....

Are there any other reasonably priced liquid chlorinators for residential pools other than the liquidator that anyone is familiar with?

Thanks,

 

[JasonLion]

Almost all commercial pools use some kind of automatic sanitizer feed system. One of the most common is a peristaltic pump pumping bleach at an adjustable rate. SWG systems are also fairly common. Chlorine gas injection is also used, though it has gotten far less common because of the dangers.

The Liquidator is the only bleach feed system for residential pools that I am familiar with. There are quite a number of commercial systems available. You can get a peristaltic pump and tank system for under $500, but you would need to figure out how to install and operate it yourself. A DIY peristaltic pump setup can be assembled for under $100 with some shopping around.

 

[chem geek]

And unfortunately there are quite a few commercial pools, such as those found in hotels, that use Trichlor feeders and yes, they have their CYA go through the roof. Sometimes this is done even with indoor pools. See this link for an example of two indoor pools at hotels that had very high (> 100 ppm) CYA levels because they used Trichlor feeders for chlorine dosing. A breakpoint chlorination spreadsheet I've made shows that such high CYA levels slow down breakpoint so that monochloramine will persist for many hours and with high bather loads will essentially build up. This is probably what caused the eye and throat irritation in these cases as they did not measure any dichloramine or nitrogen trichloride (though they thought that may have been due to dissipation, but I think those substances were in low doses since higher CYA reduces the rate of their production).

Richard

 

[Guest]

ok so high cya is bad with indoor pools, my pool regulary stayed at 90-100 all season, probably because of my feeder, so am i at risk of all that in the pdf file. some sounds nasty.

 

[Titanium]

Rollin Thunder,

Are you still using chlorine tabs or have you switched over to using liquid chlorine (i.e. bleach) yet?

The chlorine tabs are much more expensive to use than liquid chlorine, plus the chlorine tabs will continually increase your CYA levels (especially if you have a cartridge filter since cartridge filters require no backwashing).

EDIT: I see that you have a sand filter, so maybe the backwashing will keep your CYA levels under control. Or maybe not.

Titanium

 

[chem geek]

Vince,

Don't worry that you will be experiencing anything near what the CDC article reported from those hotels. First of all, your pool is outdoors. The air circulation outdoors is far better than found indoors, especially since energy efficiency has made circulation rates lower indoors. Also, outdoor pools are exposed to sunlight and the UV rays in sunlight break down the chloramines. Finally, notice how many people were in the pool and spa -- extremely high bather loads that simply overwhelmed the air circulation system (and that system was shut down at one of the hotels). I doubt that you will ever have anywhere near that many people in your own pool, even with a pool party.

My only point was that one should not assume that commercial or public pools are all well maintained. For indoor pools, I think it's pretty important to use a rather narrow range of CYA -- a small amount of around 10-20 ppm. Most indoor pools don't use any CYA and therefore overdose in disinfecting chlorine which degrades swimsuits, hair and skin (my wife complains about that when using a community center indoor pool during the winter, for example) and also may produce more of the nastier disinfection by-products (dichloramine and nitrogen trichloride). At the other extreme, having very high CYA levels leads to slow breakpoint so a buildup of monochloramine. A proper balance of a little CYA would be a good middle ground, though for these hotel incidents they simply had too many people using the pool and spa at one time so that would be hard to handle even with proper chemistry (though proper chemistry would be better than not).

Richard

 

[Guest]

OK, COOL.

Yes i still waste money with the clorine stuff. I have not convinced my wife and kids that stuff that cleans our clothes, can keep the pool clean. I talked about it at dinner one night and the kids said (8 and 9 year olds at least) DADDY THAT WOULD MAKE THE POOL BAD you should keep using the "pool tums" (thats what they call the clorine tablets) they think they make the pool feel better when its sick. KIDS.

I will most likely (with y'all's help ) switch after i open next year and get the chem's all worked out for season number 2 of the big hole in the ground.