Cal-Hypo vs. Dichlor for saltwater pool

XanderLo

New member
Jul 27, 2020
4
Montreal, Quebec
Hello,

I have been confused about the different types of shock treatments and whether or not they are harmful for the salt generator cell.
Big pool stores around here sell those relatively expensive "Salt Shock" bags that are Dichlor and apparently are suitable for the salt generator cell.

However, I have read nowhere on the internet that cal-hypo is bad for your cell. Additionally, some sites like poolcareguy explicitely state that cal-hypo is great for saltwater pools (although he mentions to turn off the generator). That makes it even more confusing!

Cal-Hypo does not contain stabilizer, is cheaper (here in Montreal at least) and is very fast and effective! I just don't want to destroy my cell. ;)

What do you experts think?
Thanks!
 

Jeff J.

Well-known member
Aug 6, 2019
223
Staten Island NY
Hello,

I have been confused about the different types of shock treatments and whether or not they are harmful for the salt generator cell.
Big pool stores around here sell those relatively expensive "Salt Shock" bags that are Dichlor and apparently are suitable for the salt generator cell.

However, I have read nowhere on the internet that cal-hypo is bad for your cell. Additionally, some sites like poolcareguy explicitely state that cal-hypo is great for saltwater pools (although he mentions to turn off the generator). That makes it even more confusing!

Cal-Hypo does not contain stabilizer, is cheaper (here in Montreal at least) and is very fast and effective! I just don't want to destroy my cell. ;)

What do you experts think?
Thanks!

I'm not an expert, but TFP doesn't recommend "shocking" your pool. Have you read Pool School on this site? Also what test kit are you using? I'll let the experts answer about the SWG.
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Welcome to TFP! :wave: Interesting you are asking about those products if you have a salt cell to create chlorine. If your SWG is operating properly, I would not be using either one of those. We generally don't "shock" a pool just for the sake of some routine once a week. If we ever suspect algae, we follow the SLAM Process. Now if my CH was actually low (in a plaster pool), I'd add calcium product. If my CH level was high, I wouldn't want to add calcium because that could increase the potential for scale to my SWG cell. If I needed to increase my stabilizer (CYA), I would buy granule stabilizer (or liquid conditioner). You can probably predict the dosage outcome better that way and save some money as well. If my SWG is struggling and I do need to increase my FC level quickly, I'll grab some liquid chlorine or regular bleach for that.

Also see our ABCs of Pool Water Chemistry for more info. Hope that helps.
 

CrystalRiver

Well-known member
Jun 19, 2020
438
Massachusetts
Neither cal hypo nor dichlor, not trichlor for that matter. Liquid chlorine only, unless I know my pool needs calcium (cal hypo) or CYA and acid (dichlor or trichlor).

With a SWCG, you shouldn't need liquid or solid chlorine, unless you are slamming because you have a problem.
 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
20,797
Bedford, TX
Lo,

Why do you think you need to add shock of any kind???

If you follow our pool care process, and keep your FC and CYA in the right relationship, you will never have to routinely "shock" your pool ever again...

See the saltwater section of this chart... FC/CYA Chart

You should also read this ... ABCs of Pool Water Chemistry

Thanks,

Jim R.
 

XanderLo

New member
Jul 27, 2020
4
Montreal, Quebec
Thank you all for the quick replies.
To answer some questions right away, details about the pool:
- 8000 gallons (18ft diameter), above ground
- The SWCG is a Jacuzzi Natrium 15

I read the linked pages (ABC, Chlorine/CYA chart and SLAM).
In my head, "shocking" is relatively similar to what's described in the SLAM page, although the SLAM process seems way more detailed and with a higher probability of success than blindly throwing a "shock bag" into the pool.

I used to test water at local store and after I had trouble keeping my water crystal clear, I went to another store. The discrepancies were extreme (the second store was using some disc where the water was inserted and it printed results right away. High tech but imprecise?). Except for CYA (which I will be testing soon with the full test kit I ordered (Pentair Pro Mini Lab Test Kit), I believe my chemistry was on point... yet, every time I would test, my FC was basically 0 even with the SWCG ON and algae would eventually start appearing.

To go through SLAM, if Cal-Hypo is not to be used, I'm reading bleach or liquid chlorine.
Can you explain what's the purpose of Cal-Hypo or Dichlor shock products? Let's say I have Cal-Hypo on hand to do SLAM, will it damage my salt cell? Why do local pool stores sell dichlor as "Shock that goes with SWG"?

Thanks again
 
Last edited:

Kjp300

Gold Supporter
Jul 18, 2018
149
Canfield ohio
SLAM is not the same as shock at all. It is a measured process to rid your pool of algae without the use of algaecides shocks clarifiers or anything else the pool store could sell you. If you maintain your FC properly you may never have to SLAM.
 

jimbethesda

Gold Supporter
Jul 2, 2018
484
Austin, TX
Can you explain what's the purpose of Cal-Hypo or Dichlor shock products? Let's say I have Cal-Hypo on hand to do SLAM, will it damage my salt cell?
You can use Cal-Hypo or Dichlor shock, but just know they will increase calcium (Cal-Hypo) or CYA (Dichlor) also. If your calcium and /or CYA are low, might be fine.
Why do local pool stores sell dichlor as "Shock that goes with SWG"?
To make money. Their marketing department came up with that tag line, and in at least your case, it worked.
 

SouthVirginiaPool

Silver Supporter
Apr 26, 2020
104
Chesapeake, Virginia
Hello,

I have been confused about the different types of shock treatments and whether or not they are harmful for the salt generator cell.
Big pool stores around here sell those relatively expensive "Salt Shock" bags that are Dichlor and apparently are suitable for the salt generator cell.

However, I have read nowhere on the internet that cal-hypo is bad for your cell. Additionally, some sites like poolcareguy explicitely state that cal-hypo is great for saltwater pools (although he mentions to turn off the generator). That makes it even more confusing!

Cal-Hypo does not contain stabilizer, is cheaper (here in Montreal at least) and is very fast and effective! I just don't want to destroy my cell. ;)

What do you experts think?
Thanks!
I thought these were great questions. I have about 6 bags of Cal-hypo left over from my pre-TFP days. I just recently had the pool partially drained to have small tears in the liner repaired by the PB. So I had to rebalance my pool chemistry after fresh water was added. Because I was adding salt to get back to 3200 ppm for the salt, I had to keep the SWG off. Pool math said that adding 1 bag of cal-hypo (16 oz) would add 3 ppm of chlorine which I needed to do for 2-3 days until the SWG was dialed back in. Since I was low on calcium too it was a win-win. I wouldn't use cal-hypo regularly, but it was safe enough to prevent a trip to Wally World for 10% chlorine. So I reason that if I am only adding 3 ppm of chlorine with the 1 bag, it probably isn't too big a load on the SWG.
 

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mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
35,972
Laughlin, NV
Pool Size
6000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
The SWCG could care less what type of 'shock' you use. The cal hypo could be an issue if you slug it right into the skimmer but that should not be done with any chemical.

The biggest risk to a SWCG is slugging it with a high salinity bolus of water. That can blow out the electronics on some units.
 

XanderLo

New member
Jul 27, 2020
4
Montreal, Quebec
Well, all of this is extremely enlightening, 100% clear now. I had been asking how certain types of shock products were *apparently* bad for the SWCG, none of them could answer me inside the big pool stores. I knew, as always, that internet forums were the best place to find the truth. ;)

I certainly got screwed a bit by marketing and erroneous info from big pool store clerks, but at least it hasn't been long.

The test kits I purchased (I already have a Taylor K1001 and ordered a Pentair Pro II Mini Lab) can't measure above 5ppm of FC unfortunately (useful when SLAMing). The K2006C is so expensive in Canada, any viable alternatives?

Thanks again
 
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Jeff J.

Well-known member
Aug 6, 2019
223
Staten Island NY
Well, all of this is extremely enlightening, 100% clear now. I had been asking how certain types of shock products were *apparently* bad for the SWCG, none of them could answer me inside the big pool stores. I knew, as always, that internet forums were the best place to find the truth. ;)

I certainly got screwed a bit by marketing and erroneous info from big pool store clerks, but at least it hasn't been long.

The test kits I purchased (I already have a Taylor K1001 and ordered a Pentair Pro II Mini Lab) can't measure above 5ppm of FC unfortunately (useful when SLAMing). The K2006C is so expensive in Canada, any viable alternatives?

Thanks again

You could order just the FAS-DPD test from tftestkits.net. It's $30 (I don't know about Canada).
 

gregsfc

Bronze Supporter
May 27, 2014
204
Cookeville,TN
Just so you know...you didn't just find one of "those internet forums"; this is THE FORUM that you want to be on. Go nowhere else or you'll get bad; sometimes even worse advice as you'll get in a pool store. Read pool school e-book. Read abc's of pool chemistry. Read Jason Lion's post "getting started". Many methodologies taught here are far different and far more correct than anywhere else. Believe me; this is where you want to be. Ask anyone that is here. Everything here is the right way.
 

Newdude

Gold Supporter
TFP Guide
Jun 16, 2019
6,161
NY
Everything here is the right way.
And for probably the only time ever, The ‘right’ way is also easy and cheap. Pretty much in any other aspect of life it is is easy and cheap you are doing it wrong. You may only have 2 of the 3. We get the trifecta.
 
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