How do you use dry shock?

[Buggsw]

I know many of you use liquid bleach, but I was surfing around today and found a Q&A site for pool care that had something interesting that I wasn't aware.

The resident expert over there said that when you use dry shock, you should not have your filter running. You should broadcast it at night and let it sit. They said that it is a "dragger" and will drag the algae, etc to the bottom of the pool.

Now, I must say that until I recently found poolforum and this place, I learned most of what I know from my local Leslies, but they told me that I should run my filter when I shock.

What say, ye experts? Have I been lead astray by Leslie's?

 

[Guest]

If you have a vinyl or dark colored plaster pool that is a good way to bleach out your liner or pool surface!
I assume they are talking about slow dissolving cal hypo. Both lithium hypochlorite and dichlor (the other 2 forms of dry chlorine sold as shock) are very fast dissoving and won't even make it to the bottom of the pool before they dissolve. Even if you shock with predissolved shock or liquid chlorine and then turn your pump off you will get some settling of any suspened matter overnight. I would say this is bad advice based on a faulty understanding of what is actually happening in the pool.
Just my 2 cents!

 

[Buggsw]

Thanks, Waterbear. I thought perhaps I've been doing it wrong for the past 6 or 7 years. The pool was here when I bought the home, so I've learned mostly from the advice of pool stores.

 

[sevver]

He sounds like a self proclaimed expert. I would never broadcast dry shock unless it was a full moon on an odd numbered day. Duh.

 

[kenlorz]

I for one always pre-dilute most all chems I add; even bleach. I just think it's safer that way.( for my liner that is) Call me paranoid but I'd rather take the time than damage a very expensive piece of vinyl....never mind replacing all that water!!!!!!!!

 

[kirbinster]

I know I do it in violation of all the rules - but I have never had a problem. I run the pump and slowly pour the dry shock into the skimmer basket. The way I see it a centrifugal pump acts as a very good mixer, and what comes out is fully dispersed. I have done this for 8 years with no adverse impact.

 

[Rob]

I'm not an expert, or even close! Only had a pool for about a month now, but for shocking, I took a large empty bucket, dump in the cal-hypo, and fill the bucket up with a hose (be careful of the spray back though, it will bleach your clothes pretty quickly, not to mention the serious danger of inhaling or getting some in your eyes).

I then move around the pool pouring off the liquid as evenly as I can. Usually, I end up with undissolved Cal Hypo in the bottom of the bucket, so I refill the bucket, and repeat till there is no cal hypo left.

I might be wrong on this, but I think the issue with adding the cal hypo directly to the skimmer basket is you end up with super chlorinated water going through your plumbing lines. The increased chlorine level will actually break down plastics, decreasing the life of your skimmer basket, any plumbing, and many of your filter parts. I don't think this is an immediate effect that you will be able to see however, more of a time thing (eg, your filter lasts 10 years instead of 15 or something).

Rob

 

[duraleigh]

Well, I'm pretty much like kirbinster. EVERYTHING except acid goes "kerplop!"directly into my skimmer, pump running....full strength.

Like Rob says, I may regret that in five years or so but I sure love doing things the easy way.

 

[kirbinster]

The chlorine levels you see will not hurt PVC piping - I used to be a process engineer in a plant that made chlorine and caustic soda.