Strange smell after adding borax

scubaspock

New member
Jul 21, 2021
3
Vancouver, Canada
First time pool: 2200gal 12ft round temporary/seasonal vinyl built and filled a week ago. Added stabilized chlorine granules and a stabilized chlorine puck in a floaty thing to start. Then I added about 25% of the recommended amount of algaecide as the box recommended for start-up. (Maybe it wasn't needed for fresh water, which is why I only used a quarter of the amount.) Initial measurements were FC=4, pH=6.7, TA=0, CH=0, CYA just above zero as per an AquaChek 7 test strip. Pool Math app recommended adding over 1kg of baking soda to increase TA and borax to raise the pH. I added 500g baking soda, waited 24hrs, and re-tested TA=40 -- perfect, half the amount raised TA by half the target. Added the other 500g and waited 24hrs and the TA=80, which was great. However, pH was still a touch low at 7.0-7.2 and the app recommended 8oz of Borax so I added half of that (4oz) and waited 24hrs. The pH raised to 7.6 but now there's an odd smell. I took a sample of water to a pool store for a professional test and they said: FC=1.1, pH=7.6, TA=118, CH=24, CYA=5 and gave me a clean go-ahead to swim. Shrugged when I asked what the smell was. (I brought enough water that you could smell it.)

The smell definitely started after adding the borax, and it persists now 48hrs later. Any ideas? It's not a typical "pool smell" (i.e. chloramine) but something entirely different. Sort of musty? Any ideas? Given it's been a ~week I thought maybe I would shock the pool just 'cause and see if that deals with it.
 

scubaspock

New member
Jul 21, 2021
3
Vancouver, Canada
Thanks, I thought the same. No, it's not well water it's from the (Vancouver) city supply, which is generally very clean. Shocked the pool last night and besides the fact that FC was still about 10 at 7AM today (maybe I added too much shock?), the smell is much reduced but not gone. I also left the pool uncovered overnight in case something just needed to off-gas.
 

Mdragger88

Bronze Supporter
Jun 1, 2018
3,359
Hernando, Ms
Pool Size
26000
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Intex Krystal Clear
I vote its the algeacide…
Also possibly cc’s. Leaving the cover off overnight for out gassing was a good idea.
Fc of 10 with no cya is quite harsh but it will be gone quickly on a sunny day.
Be sure to use PoolMath effects of adding to calculate how much cya has been added via stabilized chlorine products (trichlor/dichlor) & follow the FC/CYA Chart accordingly.
 

scubaspock

New member
Jul 21, 2021
3
Vancouver, Canada
Thanks for the replies! After the shock is now done (FC down to ~5) the smell is 99% gone. Good thing I only used 25% of the recommended algaecide, and I won't ever be adding any more that's for sure. My test strips do show total chlorine in addition to free chlorine and both are roughly equal (5) so I think that means there's zero or not much CC.
 

Mdragger88

Bronze Supporter
Jun 1, 2018
3,359
Hernando, Ms
Pool Size
26000
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Intex Krystal Clear
The strips are pretty terrible as far as accuracy goes - even if they were accurate the ranges for most of the parameters are quite broad. If you could get your hands on a 6 way drop based kit that goes to 5ppm tc for a reasonable price you should try to do that. I realize that may not be feasible in your area. There are also a few ways to get a proper fas/dpd kit in Canada incase you’re interested but they can be cost prohibitive.

Also Here’s the seasonal pool guide for small pools incase you haven’t read it 👇
 

PoolStored

Gold Supporter
Jun 24, 2021
564
Ashtabula, OH
Pool Size
31000
Surface
Vinyl
Chlorine
Liquid Chlorine
Second what @Mdragger88 said. You should get a good test kit, take a gander: Test Kits Compared Even with a small/seasonal pool, will save you so much heartache. Lots of people come to TFP with Algae and other issues that were caused by having pool store tests (inaccurate and unreliable), or worse, strips, then adding too much or the wrong chems and having issues.
 
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