Chemical smell from pool

nullspace

Member
Apr 21, 2021
9
Indoor pool
After recently shocking my pool, I now have a chemical smell that I can't quite place.

All tests done with Taylor testing kit (liquid reagents)
Free Cl: 3ppm (it's an indoor pool so I don't run high Cl levels)
Total Cl: 3ppm
Ph: 7.3 (it was too low, so I've been adding baking soda)
CYA: 0 (it was 50 - maybe it reacted with the baking soda and is gone now? I've ordered some more)
Total Alkalinity: 110

I did have some organic growth prior to the shock. The water was cloudy and free Cl had dropped to zero after a couple weeks of neglect. Now that the levels are relatively normal, I can't figure out why it smells. And I don't really recognize the smell either. Any ideas of things I could test?
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Jun 22, 2014
37,842
Texas, San Antonio/Marion, South-Central Area
Pool Size
17888
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
CircuPool RJ-45 Plus
Two things stand out to me:
1 - When you had algae, it is important that you follow the SLAM Process until you pass all 3 criteria. That's to be sure the algae is completely gone.
2 - You need some CYA. Not a lot obviously as an indoor pool, but about 20 ppm. No CYA allows the unbuffered chlorine to be exceptionally harsh, and you don't want that.

So the chlorine smell might actually be unbuffered (strong) chlorine, or residual combined chlorines from algae still being killed. Kind of like a public swimming pool smell.
 
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nullspace

Member
Apr 21, 2021
9
Indoor pool
That's a really good point - until now I've had decent levels of CYA, so maybe that's why I'm noticing a difference. My shipment of CYA arrives today; I'll see if that solves the issue after a day or two.

I wasn't aware of SLAM as a separate thing, but I did those tests as part of my normal process and passed all 3.