Indoor pool test results

crabboy

LifeTime Supporter
Jul 24, 2007
528
0
Suwanee, GA
#1
I've been taking my kids to swim lessons at an indoor pool since the summer and they always come back reeking of chlorine. I've wanted to test the water myself, but never remembered to bring a bottle. Well today I took my bottle and grabbed a small sample. Here are the results:

FC = 13
CC = 3
CYA = 0
PH = 7.8 - 8.2
TA = 16
CH = 210

This was from the pool that all the little kids are in, I'll test the others over the next few times I go. My kids do swim in this pool when they are done, but spend most of the time in a larger pool. I'll sneak a peek at that one next time.
 
G
#3
It is possible that the FC is actually higher then you tested but it lost strength by the time you got it home to test. IF this is true then the chlorine could be high enough to cause the pH test to be reading high. I would almost bet that the pH is actually too low, which is why the TA is reading so low! (assuming you are using Taylor test reagents or the TFTestkit.)
 
G
#8
some of the Rainbow (Pentair) kits have a phenol red that has chlorine neutralizer built in and some of them don't. If yours has the one with the neutralizer included in the reagent it is as accurate at the Taylor or TF100. If not you will get a high pH reading with chlorine levels not much above 3 ppm!
 

chem geek

LifeTime Supporter
TFP Expert
Mar 28, 2007
12,082
2
San Rafael, CA USA
#9
I think the main problem here is that this indoor pool is WAY over-chlorinated. It's bad enough to have "normal" Free Chlorine levels (say, 2 ppm or so) in an indoor pool with no CYA, but to have 5+ ppm with no CYA (and at least 13 ppm FC in your case) is a heck of a lot of chlorine. You should really complain to the owner of the facility and have them get the chlorine level more in line. At those high chlorine levels, it's not just a matter of faster swimsuit degradation and skin flaking and hair frizzing, but the amount of smelly disinfection by-products, specifically nitrogen trichloride, may be close to levels that can cause respiratory and ocular problems.

I assume the 13 wasn't the number of drops in the FAS-DPD chlorine test. If it was and the sample was a 25 ml sample size, then that's really 2.6 ppm FC; if the sample size was 10 ml, then 13 drops would be 7.5 ppm FC.

Richard
 
G
#10
wow, i need to turn down my clorinator then. my pool read 15ppm for clorine all year. no wonder it felt funny to swim, were hurting our lungs. but never a smell and you only get the clorine smell with CC.

every indoor pool i swim in always smells like clorine, im guessing because they never get rid of the CC's/
 

crabboy

LifeTime Supporter
Jul 24, 2007
528
0
Suwanee, GA
#11
13 is the correct FC reading because I remember laughing when it hit 20 drops, to a total of 26 with a 10ml sample.

The Pentair kit that I've been using has a separate 'chlorine neutralizer' that gets added before the ph drops. I've found this one easier to match the colors over the Taylor one that was included with the TF kit.

Thanks for your input guys.
 

chem geek

LifeTime Supporter
TFP Expert
Mar 28, 2007
12,082
2
San Rafael, CA USA
#12
Rollin Thunder said:
wow, i need to turn down my clorinator then. my pool read 15ppm for clorine all year. no wonder it felt funny to swim, were hurting our lungs. but never a smell and you only get the clorine smell with CC.

every indoor pool i swim in always smells like clorine, im guessing because they never get rid of the CC's/
Vince,

Your pool is outdoors, isn't it? So it has CYA in it, doesn't it? In that case, 15 ppm FC isn't as high as you might think, depending on the CYA level. If it's an SWG pool with 80 ppm CYA for example, then the 15 ppm FC is equivalent to 0.2 ppm FC with no CYA so isn't horribly high. It's still higher than needed to prevent algae, but is far lower than found in indoor pools that have no CYA.

Some indoor pools do have CYA -- too much CYA -- because they use Trichlor feeders. In that case, the high CYA can lead to a slow breakpoint so monochloramine builds up and that can smell. At the other extreme, with no CYA, the breakpoint is too fast and you get more nitrogen trichloride which is really smelly and irritating. Usually, though, you don't get these situations unless the bather load is high, but in many commercial and public pools that is the case.

Richard
 
G
#13
chem geek said:
[quote="Rollin Thunder":1mb1orgz]wow, i need to turn down my clorinator then. my pool read 15ppm for clorine all year. no wonder it felt funny to swim, were hurting our lungs. but never a smell and you only get the clorine smell with CC.

every indoor pool i swim in always smells like clorine, im guessing because they never get rid of the CC's/
Vince,

Your pool is outdoors, isn't it? So it has CYA in it, doesn't it? In that case, 15 ppm FC isn't as high as you might think, depending on the CYA level. If it's an SWG pool with 80 ppm CYA for example, then the 15 ppm FC is equivalent to 0.2 ppm FC with no CYA so isn't horribly high. It's still higher than needed to prevent algae, but is far lower than found in indoor pools that have no CYA.

Some indoor pools do have CYA -- too much CYA -- because they use Trichlor feeders. In that case, the high CYA can lead to a slow breakpoint so monochloramine builds up and that can smell. At the other extreme, with no CYA, the breakpoint is too fast and you get more nitrogen trichloride which is really smelly and irritating. Usually, though, you don't get these situations unless the bather load is high, but in many commercial and public pools that is the case.

Richard[/quote:1mb1orgz]

yes she is outdoors :wink:


my chems are all screwed up and i plan on fixing it this new season now that i have aton more time on my hands thanks to a little thing called retirement 8)

but my last CYA reading was like 210 (NO NOT A TYPO) the dot disapeared with only like 1/4 of an inch of water in there, had my son check it too and he said he could not see the dot also (at waist level like the box says) so does this mean i need to drain and refill then, because if i do i want to ready my check book as thats alot of dollars worth of water. :shock:
 
G
#14
crabboy said:
13 is the correct FC reading because I remember laughing when it hit 20 drops, to a total of 26 with a 10ml sample.

The Pentair kit that I've been using has a separate 'chlorine neutralizer' that gets added before the ph drops. I've found this one easier to match the colors over the Taylor one that was included with the TF kit.

Thanks for your input guys.
This is the kind that will read high when the chlorine gets aroudn 3 ppm or so!
 

chem geek

LifeTime Supporter
TFP Expert
Mar 28, 2007
12,082
2
San Rafael, CA USA
#15
Rollin Thunder said:
yes she is outdoors :wink:


my chems are all screwed up and i plan on fixing it this new season now that i have aton more time on my hands thanks to a little thing called retirement 8)

but my last CYA reading was like 210 (NO NOT A TYPO) the dot disapeared with only like 1/4 of an inch of water in there, had my son check it too and he said he could not see the dot also (at waist level like the box says) so does this mean i need to drain and refill then, because if i do i want to ready my check book as thats alot of dollars worth of water. :shock:
Ah, so the "auto-chlorinator" is probably a Trichlor feeder. For every 10 ppm Free Chlorine (FC) added by Trichlor, you are also adding 6 ppm to Cyanuric Acid (CYA) so that built up over time. You eventually will need to dilute your water, but don't have to do so all in one shot which is more expensive. In the meantime, with a CYA of 210 ppm, you would need to have a minimum of 16 ppm FC to keep away green algae so that's about what you've got right now. However, to keep the CYA from continuing to increase, you should consider switching to using chlorinating liquid and possibly getting The Liquidator (see this thread for more info) for automated dosing. If you regularly backwash your sand filter, then you should dilute your water over time and the CYA will get lower (assuming you stop using Trichlor tabs or Dichlor powder/granules).

Your other alternative that would let you use a lower chlorine level, perhaps half (so around 7 ppm) would be to use an algaecide such as PolyQuat 60 weekly. However, this can get expensive.

Richard
 
G
#16
chem geek said:
[quote="Rollin Thunder":2w35lvsb]
yes she is outdoors :wink:


my chems are all screwed up and i plan on fixing it this new season now that i have aton more time on my hands thanks to a little thing called retirement 8)

but my last CYA reading was like 210 (NO NOT A TYPO) the dot disapeared with only like 1/4 of an inch of water in there, had my son check it too and he said he could not see the dot also (at waist level like the box says) so does this mean i need to drain and refill then, because if i do i want to ready my check book as thats alot of dollars worth of water. :shock:
Ah, so the "auto-chlorinator" is probably a Trichlor feeder. For every 10 ppm Free Chlorine (FC) added by Trichlor, you are also adding 6 ppm to Cyanuric Acid (CYA) so that built up over time. You eventually will need to dilute your water, but don't have to do so all in one shot which is more expensive. In the meantime, with a CYA of 210 ppm, you would need to have a minimum of 16 ppm FC to keep away green algae so that's about what you've got right now. However, to keep the CYA from continuing to increase, you should consider switching to using chlorinating liquid and possibly getting The Liquidator (see this thread for more info) for automated dosing. If you regularly backwash your sand filter, then you should dilute your water over time and the CYA will get lower (assuming you stop using Trichlor tabs or Dichlor powder/granules).

Your other alternative that would let you use a lower chlorine level, perhaps half (so around 7 ppm) would be to use an algaecide such as PolyQuat 60 weekly. However, this can get expensive.

Richard[/quote:2w35lvsb]


im not in to the pool lingo yet :lol: im guessing auto clorinator is more like the salt system. which this season im planning on upgradeing too anyway. but i just thought that somthing that added the clorine in there my self with out having to measure it was auto DOH. but yes i throw the giant rollaids in there :lol: usually put about 10 pucks in and refill twice a week. too much? its costing me a ton in clorine so i may switch to bleach before i upgrade to a salt system.
 

chem geek

LifeTime Supporter
TFP Expert
Mar 28, 2007
12,082
2
San Rafael, CA USA
#17
Rollin Thunder said:
im not in to the pool lingo yet :lol: im guessing auto clorinator is more like the salt system. which this season im planning on upgradeing too anyway. but i just thought that somthing that added the clorine in there my self with out having to measure it was auto DOH. but yes i throw the giant rollaids in there :lol: usually put about 10 pucks in and refill twice a week. too much? its costing me a ton in clorine so i may switch to bleach before i upgrade to a salt system.
Well, it's up to you, but for every 10 ppm FC you are adding with Trichlor you are also adding 6 ppm to CYA. I think you would be better off going to chlorinating liquid, but of course you do want SOME CYA though that won't be a problem since you can just do partial drain/refill and backwash over time until the CYA drops to some reasonable amount around 30-50 ppm or so. If you do get a saltwater chlorine generator (SWG), then the CYA level recommended may be closer to 60-80 ppm. Right now, you may be finding an unusually high chlorine demand due to algae growth that you can't quite see yet (the water would start to turn dull and then cloudy before it turns green if algae takes off). That's what happened to my own pool years ago when I used Trichlor and my CYA got up to around 150 ppm -- I noticed the chlorine was getting used up faster "mysteriously" though now I know what was really going on. At your current high FC level, you're probably just keeping algae away.

Richard