Hot Tub Forum

Original => Hot Tub Forum => Topic started by: TLWR on July 15, 2012, 11:22:27 am

Title: How do I shock?
Post by: TLWR on July 15, 2012, 11:22:27 am
I have a small 300gal tub w/mineral stick, ozone and a circ pump.
I did a water change yesterday, the water became cloudy 2 days prior to the 4 month mark (new tub) I assumed the mineral stick has been used up, as that is the max advertised lifespan.

My routine for water maintenance (2 adult users) is 1TBS MPS after daily use, and 1TBS Diclor once per week.

I've never shocked the tub, never thought I needed it in the last 4 months. But it occured to me that if I do, I don't know how to shock it. Since I use MPS daily after use, do I shock with MPS, or with diclor, and how much?

When I bought it, the dealer said if the water were ever cloudy, just add 1TBS each of MPS and diclor, is that my shock routine?
Title: Re: How do I shock?
Post by: Jacuzzi Jim on July 15, 2012, 11:30:49 am
 MPS is shock, so you are basically shocking after use.   If your water is staying good in that 4 months your doing it right.   I like to hit mine hard with chlorine (dbl dose) every couple of weeks just to keep things clean.  I have seen with your method people getting bio film after time with that way.    It looks like dead skin floating around.    Sounds like your doing good..
Title: Re: How do I shock?
Post by: TLWR on July 15, 2012, 07:46:32 pm
thank you
Title: Re: How do I shock?
Post by: goose973 on July 15, 2012, 08:02:05 pm
Unless you're only using the tub a couple of times a week, to go four months in a small tub without a water change sounds excellent to me. I can only make it about two before I have to change. We use our tub with two of us almost every day, though. Also, my wife likes to use a lot of lotion.
Title: Re: How do I shock?
Post by: TLWR on July 15, 2012, 10:57:02 pm
we use the tub daily during the week and usually twice on weekends. We shower before each use, and usually use the tub just before bed daily and also when we get up on weekends. Just got out as a matter of fact.
Title: Re: How do I shock?
Post by: chem geek on July 16, 2012, 03:38:52 am
When using MPS to oxidize most bather waste, you don't build up the Cyanuric Acid (CYA) level as you would if you were using Dichlor only.  Those using the Dichlor-then-bleach method also find they can go about twice as long between water changes.  The reason those using only Dichlor can't go as long is that the CYA level builds up and makes chlorine less effective to the point that it doesn't oxidize bather waste quickly enough (it also doesn't disinfect as quickly either).

If you had Nature2 with silver ions, then that with the MPS would be a fast disinfectant and is EPA-approved.  Using MPS alone is a little riskier, though in hot spa water not terribly so.
Title: Re: How do I shock?
Post by: wmccall on July 16, 2012, 07:47:46 am
Keeping the tub looking good for 4 months on a new tub is excellent.  While I'm just another user,  we have a similar sized tub and its just my wife and  I 95% of the time.  I give a small dichlor dose after we get out each night and add MPS once a week as the shock.
Title: Re: How do I shock?
Post by: Chas on July 16, 2012, 04:11:23 pm
This question seems to have been answered nicely, but here's a bit more info for other readers:

When you shock with Dichlor, it is a good idea to test the next day to see if you have successfully reached your goal. I always recommend measuring with something more accurate than 'a capful.' So let's say you put in four tablespoons full of Dihclor, and then the next day you test. If you have a readable level of chlorine, then you are good to go. But if you have NO readable level of chlorine, it means that there were more contaminants in the water than the chlorine could sanitize, and you have NOT shocked your tub.

After you have owned a tub for a while, you will tend to be able to manage most levels by sight or smell, but I am still a stickler on the shock: test the next day. I think the reason I have such a strong opinion on this is because a lot of us will only shock after the tub goes bad, OR after we have entertained in our tub. In other words, quite often the shock is being done to correct something, and I want to be sure we do, in fact, correct it.

That is all, we now return to our regularly scheduled.....

 8)
Title: Re: How do I shock?
Post by: lyncch00 on July 20, 2012, 08:58:01 pm
My tub is 325 gallons.  I switched from baquaspa to MPS.  Baquaspa laft sludge here and there.  MPS is squeaky clean.  Without knowing how many gallons I had, the salesperson told me to use 3 teaspoons MPS daily after final use, and one teaspoon dichlor a week to shock.  He said gallons didn't matter.  I also have an ozinator and nature 2 silver spa insert.  I've been doing it for 2 months now.  So far, no issues.  I switched from the SPA store chemicals to MPS from Lowes and Dichlor from Walmart.  Much cheaper.  Do the dosages sound right? 
Title: Re: How do I shock?
Post by: chem geek on July 24, 2012, 09:49:58 pm
Your dealer is correct that your daily dosing after using a spa is independent of spa size (good for them for figuring that out).  3 teaspoons of MPS would handle around a half-hour of one person soaking if you didn't have any ozonator.  With an ozonator, that amount of MPS might handle up to one person-hour of soaking (so two people for 30 minutes) but that really depends on the strength of your ozonator and how long it runs.  The bottom line is that you measure a residual of MPS before your next soak so you adjust your dosage up/down accordingly to make that happen.  You just don't want it to get towards zero -- that's when you'll run into problems.  As for the weekly shock, that's fine and is only needed to clear some chemical contaminants that the MPS and ozone may not.
Title: Re: How do I shock?
Post by: Philpug on July 25, 2012, 12:35:51 am
MPS is shock, so you are basically shocking after use.   If your water is staying good in that 4 months your doing it right.   I like to hit mine hard with chlorine (dbl dose) every couple of weeks just to keep things clean.  I have seen with your method people getting bio film after time with that way.    It looks like dead skin floating around.    Sounds like your doing good..
Is it recommended to use Chlorine even if you're using bromide based chemicals?
(apologies if this has already been answered)
Title: Re: How do I shock?
Post by: chem geek on July 26, 2012, 03:39:48 am
If you using bromine and assuming you've built up or created a bromide bank, then adding any oxidizer, chlorine included, will oxidize bromide to bromine.  That is, it creates more bromine.  The main advantage to using chlorine for this purpose is that it can oxidize some things better than bromine so in the brief time (minutes) before it reacts with bromide to create bromine it can sometimes clear up the water directly on its own.