Pool Water smells like "stinky"

harleysilo

TFP Expert
LifeTime Supporter
Mar 1, 2012
1,924
North Georgia
TF-100 results

FC 8
CC <.5
CYA 30
PH 7.5
TA 70
CH 90
Borates 30 or 50, probably 50
Temp Average 92 with spikes to 96 or higher, never below 89.
Water clear and sparkling

Pool covered with Auto cover at all times except for swimming.
Swimming average 1 hour every other day during week, 3 hours on weekend.

So the kids reported the pool was “stinky” the other day. I got in and noticed something too. The neighbor was mowing his grass, I attributed it to the smell of cut grass although it didn’t really smell like that. It smells more like dead lizards, or dead frogs, or compost maybe. We do get every other day or so dead lizards, frogs, bugs, moths, centipedes etc. I empty the skimmer basket every day.

As I’m writing all this out, I’m wondering, if my chlorine level never drops too low, I shouldn’t smell this. I guess it could be something in the yard wafting over the pool, or maybe something rotting in the Auto cover pit. But I smell whatever it is when I get in the water and get my nose right down on the surface.

I thought about shocking, but it takes forever for my pool to drop back down to normal chlorine levels, but will do if it’s the only idea to try. I guess I don’t understand what could be stinking with chlorine in the pool.
 

harleysilo

TFP Expert
LifeTime Supporter
Mar 1, 2012
1,924
North Georgia
Brushpup said:
Simple answer if you ask me.....just swim under water..... :snorkle:
LOL :snorkle:

Seriously thou went swimming last night and didn't smell it. I didn't expect many responses, cause its going to be one of those "everything should be just fine" issues. I'll keep my nose out and see if/when i smell it again i can correlate it to something.
 

Butterfly

TFP Expert
LifeTime Supporter
May 30, 2007
10,045
South Carolina
Pool covered with Auto cover at all times except for swimming.
Swimming average 1 hour every other day during week, 3 hours on weekend.
I think that could be the culprit. Pools need to breath. Try removing cover every day for at least a few hours.

And, when you shock the pool, you should leave the cover off during the day to allow the sun to help burn off CC's. Having the cover on during shocking is the reason your pool takes so long to come back down to normal levels.
 

harleysilo

TFP Expert
LifeTime Supporter
Mar 1, 2012
1,924
North Georgia
Butterfly said:
Pool covered with Auto cover at all times except for swimming.
Swimming average 1 hour every other day during week, 3 hours on weekend.
I think that could be the culprit. Pools need to breath. Try removing cover every day for at least a few hours.

And, when you shock the pool, you should leave the cover off during the day to allow the sun to help burn off CC's. Having the cover on during shocking is the reason your pool takes so long to come back down to normal levels.

I think so too. I haven't purposely shocked the pool since it was installed last summer. During the process of dialing in the SWG i've gotten up to a level of 16ppm of FC, but it was not intintional.

So for arguments sake, what exactly would be building up that would cause the smell? And during the breathing process (outgassing) what is really going on? Is this aking to an indoor pool in essence?
 

chem geek

TFP Expert
LifeTime Supporter
Mar 28, 2007
12,083
San Rafael, CA USA
When chlorine oxidizes ammonia and organics, it produces not only gasses you don't smell such as nitrogen gas and carbon dioxide, but also produces gasses you can smell including monochloramine (though in practice it takes a lot before you smell this), dichloramine and nitrogen trichloride. If you keep the pool covered, then these gasses are not able to get out of the pool so they build up in the pool water until you remove the cover at which point you can smell them. Also, if the pool cover is mostly opaque, then the UV in sunlight is unable to get into the pool and UV helps break down the most smelly of these gasses (it doesn't affect monochloramine very much).

If your pool were very clean and free of organics and ammonia to react with, then the cover wouldn't matter unless the chlorine were to react with the cover itself.

Normally you shouldn't need to uncover the pool every day. Our pool has gone through different levels of use but when used every other day we've never noticed any problems with odor. It's more of a problem if you have heavy usage, such as a pool party, and then cover it up right away. Then, when you open it up again you could have the "bad pool smell" similar to higher bather-load indoor commercial/public pools. If you uncover the pool an hour or so before you are going to use it, that should be enough to prevent a bad smell. That's what usually works for spas, though even 10 minutes with the jets running is sufficient to clear out any of the most volatile dissolved gasses.

I think you're situation was just something transient, perhaps something that got into the pool that you were not aware of or perhaps something not related to the pool at all but you associate it with the pool because you were using it at the time the odor wafted through.