Pool stabilizer via the spa?

Poiks

Well-known member
Jun 22, 2019
50
McKinney, TX
Hi all,

I've struggled to find a way to add CYA to my pool without leaving my pump running for 48 straight hours (sock method). One thing I've tried this weekend which seems to work great is to dangle the sock in the spa, run the pool in spa mode, and turn the blower on. This seems to agitate the sock enough to to dissolve the CYA significantly faster. So before I congratulation myself--is there any reason why this wouldn't be a good idea?

Thanks!
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
25,665
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
How many gallons in your spa?

How much CYA are you adding?

Stablizer/CYA is a mild acid and will lower your pH. Putting a lot of stabilizer in a small body of water can lower your pH below 7. Hard to know how much of an acid bath you are giving yoru spa without doing the calculations.

Better to run your VS pump on a low speed for 24 - 48 hours when adding CYA. It should cost you less than a cup of coffee.
 

Poiks

Well-known member
Jun 22, 2019
50
McKinney, TX
Ah, interesting. Not sure about the spa gallons but I assumed there was enough water interchange between the pool and spa to distribute the acid. I was adding 10.5 oz that
way.
 

Mdragger88

Bronze Supporter
Jun 1, 2018
2,220
Hernando, Ms
Pool Size
26000
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Intex Krystal Clear
How often are you squeezing your sock when hanging it in front of a pool return? I can generally dissolve a couple pounds in an hour or two if i give it a squeeze every now & then after it’s been sitting there a bit.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
25,665
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
Ah, interesting. Not sure about the spa gallons but I assumed there was enough water interchange between the pool and spa to distribute the acid. I was adding 10.5 oz that
way.

You didn't say if you had your spillover running and water flowing into the pool when you did it
 

Poiks

Well-known member
Jun 22, 2019
50
McKinney, TX
You didn't say if you had your spillover running and water flowing into the pool when you did it
Sadly I am still mostly a noob so I don't completely understand the plumbing of the pool/spa combo. Obviously it doesn't mix in very much pool water when it's in spa mode, or the spa would have to work much harder to stay hot. But in pool mode, there's a jet in the bottom of the that also is active, so maybe that's the right approach--pool mode, air blower on. I dunno. Last time I try to add conditioner to pool it took about 36 hours even with frequent squeezing of the sock.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
25,665
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
Last time I try to add conditioner to pool it took about 36 hours even with frequent squeezing of the sock.

That's ok. Just be patient.
 
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mgtfp

Bronze Supporter
Mar 5, 2020
975
Melbourne, Australia
Pool Size
66000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Astral VX 7T
I would not recommend that. In my case, the spa has a volume of about 2% of the pool volume, I assume that is kind of typical.

If starting at CYA 50 and pH 7.5, I added 10ppm worth of CYA to the pool, pH would drop to about 7.3.

If I added the same amount to the spa, without water exchange to the pool, CYA would rise to 600ppm and pH would drop to 6.1. That combination of high CYA and low pH will result in a very low CSI, not good for plaster surfaces. The aeration by the blower might improve things a bit. Also, at CYA 600ppm in the spa, your FC will be useless.

To give you an example of the differences between pools and spas: In a pool, you add MA for pH adjustments in more like gallon quantities. In a spa, you add MA by the tea spoon.
 
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