Need to shock if using SWCG?

[JimK]

I've always assumed that a SWCG was just to maintain a constant chlorine level and that regular shocking was still needed. However, I came across this from a moderator (with the same username as someone here, Waterbear; same person?) on the PoolSpaForum:

"...In general boost is used to '"shock" a pool and salt pools rarely, if ever, need shocking when properly maintained..."

Is this correct?

I shock every two weeks or after a big rain (enough that requires I pump excess water out). Bather load for our pool is very light (only two adults in the household; maybe 1 small pool party a year).

Am I just wasting my money?

[CarlD]

Jim,
One of the principles of the B-B-B system is regular testing. I advocate spending 2 minutes a day testing your chlorine and pH levels, which, with a decent OTO/pH kit. We also advocate a full weekly suite of testing with a proper FAS-DPD chlorine test kit, including FC (free chlorine), CC (combined chlorine) TC (total chlorine which = FC + CC), pH, TA (Total Alkalinity) and CYA/Stabilizer. If you have a concrete or tile pool, or other hard substance, we suggest the CH, for calcium hardness levels.

With proper testing you will never guess about when to shock and when not to. If your pool is properly maintained, your FC is consistently in the proper range for your CYA level, your CC is 0, and your pH is good, then, unless you have algae or someone defecates or vomits in your pool, you have no reason to shock it. This is true whether you have an SWCG unit or not (I don't).

The key is "When Properly Maintained" -- and the only way to do that is with consistent testing and prompt correction of little problems before they become big ones. Ultimately, it saves you vast amounts of both time and money.

Now I'm not the expert on SWCG systems but here's what I do know: Most manufacturers recommend a CYA level of 60-90ppm. Check your manual. Whatever your CYA level is, your FC level should always be AT LEAST 5% of that. So with a CYA level of 60, your FC should never be below 3ppm. CYA=80ppm? FC should be above 4ppm.

If you get into a situation where you have significant CC levels (above .5) you'll need to shock your pool. The BEST shock to use with an SWCG is good old bleach/liquid chlorine. It just works with the least side effects.

But...back to your original question, no, you don't simply shock for shocking's sake. You do it when you need to. On good test kit (we recommend the Taylor K-2006--you can get to it by the link in my sig) will pay for itself many, many times over its initial cost.

BTW, I'm pretty sure it's our same Waterbear--and his advice is sound.

[Watermom]

It is the same Waterbear!

[waterbear]

Yep, it' me! I get around.:cool:
You only really need to shock if there is persistent CC and that does not happen that often in a properly maintained pool, SWCG or not. Pool stores and chemical companies will tell you to shock weekly and they make a lot of profits selling you "shock" as if it were a special type of chlorine!

[CarlD]

Sure glad, 'cuz that other 'Bear seemed to know what he was talking about...and I wuz thinkin' we'd have to 'cruit him! :)

[waterbear]

Sure glad, 'cuz that other 'Bear seemed to know what he was talking about...and I wuz thinkin' we'd have to 'cruit him! :)

NOT a bear at all, more of a moss piglet.

[CarlD]

NOT a bear at all, more of a moss piglet.

Now THAT is TMI! LOL!

[waterbear]

Now THAT is TMI! LOL!

Google it Carl! (A tardigrade by any other name..., to paraphrase Shakesphere)

[JimK]

Jim,
One of the principles of the B-B-B system is regular testing. I advocate spending 2 minutes a day testing your chlorine and pH levels, which, with a decent OTO/pH kit. We also advocate a full weekly suite of testing with a proper FAS-DPD chlorine test kit, including FC (free chlorine), CC (combined chlorine) TC (total chlorine which = FC + CC), pH, TA (Total Alkalinity) and CYA/Stabilizer. If you have a concrete or tile pool, or other hard substance, we suggest the CH, for calcium hardness levels.

Thanks, I have that covered. I learned years ago that I needed to do my own testing using quality test kits and test on a regular basis.


With proper testing you will never guess about when to shock and when not to. If your pool is properly maintained, your FC is consistently in the proper range for your CYA level, your CC is 0, and your pH is good, then, unless you have algae or someone defecates or vomits in your pool, you have no reason to shock it. This is true whether you have an SWCG unit or not (I don't).

Bingo! This is the information I was seeking. With all the research I've done over the years this is the first time anyone has explained this to me. I've mentioned before about my shock schedule and no one has questioned it. Usually the only time I find measurable CC is during spring cleanup. The rest of the season I almost never find any CC (for reference, I've been using the Taylor FAS-DPD chlorine test kit for years; I love it!)


The key is "When Properly Maintained" -- and the only way to do that is with consistent testing and prompt correction of little problems before they become big ones. Ultimately, it saves you vast amounts of both time and money.

Agree 100%. I've always been a bit anal about caring for my pool. The main hurdle has been all the inaccurate and often contradictory information out there. For someone who is learning it is very confusing and is difficult to tell who knows what they are talking about and who doesn't. This is our first pool, installed in 2004, and I've been learning ever since.


Now I'm not the expert on SWCG systems but here's what I do know: Most manufacturers recommend a CYA level of 60-90ppm. Check your manual. Whatever your CYA level is, your FC level should always be AT LEAST 5% of that. So with a CYA level of 60, your FC should never be below 3ppm. CYA=80ppm? FC should be above 4ppm.

Being the type person I am, I thoroughly read the SWCG manual when it was installed (2004) and refer to it regularly if I have a question (it has a great charts on adding/maintaining salt and CYA). The recommended CYA level for my SWCG (Aquarite) is 60-80. I always strive to maintain FC at about 5 (+/- 1)


If you get into a situation where you have significant CC levels (above .5) you'll need to shock your pool. The BEST shock to use with an SWCG is good old bleach/liquid chlorine. It just works with the least side effects.

As I mentioned earlier, I almost never see any measurable CC levels outside of spring cleanup (must be all that excess shocking...lol). I'll stop the regular shocks and just shock as needed. It will be interesting to see how often/if ever, I need to shock.


But...back to your original question, no, you don't simply shock for shocking's sake. You do it when you need to. On good test kit (we recommend the Taylor K-2006--you can get to it by the link in my sig) will pay for itself many, many times over its initial cost.

Thanks again. I appreciate the education. I agree about having a good test kit(s) and using it. I've been preaching this for many years to my coworkers who also have pools.


BTW, I'm pretty sure it's our same Waterbear--and his advice is sound.

Understood.

[waterbear]

"Our same waterbear"? I feel like a pet!:D The info has been in my sig here ever since they asked me to mod over at PSF.

[JimK]

Google it Carl! (A tardigrade by any other name..., to paraphrase Shakesphere)

Just looked it up........dang, tough little critters, aren't they!

[CarlD]

"Our same waterbear"? I feel like a pet!:D The info has been in my sig here ever since they asked me to mod over at PSF.

Could be worse...my wife REALLY spoils our dogs and cats. One dog looks like my avatar, the other is similar but colored like a German Shepherd (Belgian Tervuren).
In fact, if reincarnation is real, I want to come back as one of my wife's cats--or dogs! It's a great life!