How much MPS do I use for initial shock?

Jun 18, 2015
72
Oklahoma City, OK
I apologize, but I cannot find the answer to this. Would someone please point me in the right direction? I have a 1000 gallon spa and I know how much my spa guy told me to use to shock after each use, but now that I have changed to bromine I didn't know if this changed. Thank you for helping this newbie!
 
This was already covered in this post where I wrote:

As for how much oxidizer to add after each soak, the rough rule-of-thumb with no ozonator and a hot (104ºF) spa is that every person-hour requires 3-1/2 teaspoons of Dichlor or 3-1/2 fluid ounces of 8.25% bleach or 7 teaspoons of non-chlorine shock (43% MPS) to oxidize bather waste. The real rule is to add whatever you need to so that you still have roughly 2-4 ppm Bromine for the start of your next soak. Note that the bromine tab feeder should be adjusted so that it maintains a background bromine level in between soaks -- you do not use it to try and oxidize your bather waste after each soak unless you plan on being VERY consistent with your usage.

The amount of oxidizer that needs to be added after each soak is the same whether you are using chlorine or bromine, assuming you are using your bromine tab feeder only to handle background dosing in between soaks.
 
This was already covered in this post where I wrote:



The amount of oxidizer that needs to be added after each soak is the same whether you are using chlorine or bromine, assuming you are using your bromine tab feeder only to handle background dosing in between soaks.

Sorry, I thought the amount would be different for the initial shock since nobody has been in it. Thank you.
 
No, I'm sorry because I didn't understand you meant "initial shock" before anyone got in the water (you wrote "shock after each use"). You don't really need to do any sort of "initial shock" because presumably your water is good after a water change. Instead you just want to add enough oxidizer to get the bromine level to where you want it, so roughly 2-4 ppm so that it is ready for your soak or is at the background level that the bromine tabs will maintain.

So if you are starting from 0, then 2.25 - 4.5 ppm bromine in 1000 gallons would need 1-1/2 teaspoons of Dichlor or 1-1/2 fluid ounces of 8.25% bleach or 3 teaspoons of non-chlorine shock (43% MPS).
 
No, I'm sorry because I didn't understand you meant "initial shock" before anyone got in the water (you wrote "shock after each use"). You don't really need to do any sort of "initial shock" because presumably your water is good after a water change. Instead you just want to add enough oxidizer to get the bromine level to where you want it, so roughly 2-4 ppm so that it is ready for your soak or is at the background level that the bromine tabs will maintain.

So if you are starting from 0, then 2.25 - 4.5 ppm bromine in 1000 gallons would need 1-1/2 teaspoons of Dichlor or 1-1/2 fluid ounces of 8.25% bleach or 3 teaspoons of non-chlorine shock (43% MPS).

Thanks again! Crossing fingers that things will go well. Bromine level is at 5.5 right now. Ph finally coming down!
 
Add some more oxidizer and make sure your bromine floater is opened up all the way with bromine tabs in it. You may have leftover bromine demand from something. If you continue to have high demand, then you might need to use the Ahh-Some as the Swirl Away may not have been enough. A normal spa should not be losing more than 25% of the disinfectant over a 24-hour period when there is no bather load (i.e. the 24-hour loss period starts at least 24-hours after bather load with sufficient oxidizer was added).
 
Thank you.....again! It is opened up all the way and I filled it up with the tabs. I have had the spa open all day because I keep testing and running and adding things. My husband thinks maybe that is affecting my levels. The temp. is also up to 92° from 87° because of the heat outside. I know these things may not matter, but I'm just trying to figure out what the heck I'm doing wrong here. I waited almost 2 hours after starting the floater to test again. Was that too soon? Maybe I should add bleach this time since I used MPS earlier?
 
The floater only adds bromine more slowly, but the problem is that the bromine you already had in the spa went away. Bleach or MPS shouldn't matter. Technically, the bleach converts the bromide to bromine very quickly, within a minute, while the MPS takes longer but should still be within the hour at most. Sure, you can try adding bleach this time just in case there's something wrong with the MPS product.

What else are you adding? You probably shouldn't be adding other things, at least not what we recommend. Something you added might have reacted with the bromine in the water.
 

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I only put in the ph/alk decreaser this morning because the ph was at 8. After that, I put in the Broma-Start and then the MPS. I then tested and bromine was at 5.5. I started my floater with the tabs in it also. I have done nothing since then and now the bromine is at 0. I really question these products the spa place sold us. This oxidizer obviously wasn't keeping our ick out of the water when we put it in every time we used it in the beginning.

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Should I just leave the ph alone at this point (it's down to 7.2 now) and work on the bromine? I didn't want to add anything else at the same time I was trying to get the bromine going.

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I apologize for being a pain!
 
Yes, just work on the bromine by adding bleach. You aren't a pain -- I was just checking to make sure nothing weird was being added. Add 3 fluid ounces of 8.25% bleach which should get you to 4.5 ppm bromine. Test the water after circulating, say within 30 minutes. If you don't measure enough bromine, add more bleach. If it's used up very quickly, then go ahead and shock with three times as much bleach -- 9 fluid ounces. If that still doesn't hold, then I would suggest you get the Ahh-Some and use it and then dump/refill. You might have some serious biofilms in your plumbing and Swirl Away isn't nearly as good as Ahh-Some at getting rid of it.

Also, if you haven't cleaned your filter in a while, you should take a look at it and clean it if it's dirty.
 
Yes, just work on the bromine by adding bleach. You aren't a pain -- I was just checking to make sure nothing weird was being added. Add 3 fluid ounces of 8.25% bleach which should get you to 4.5 ppm bromine. Test the water after circulating, say within 30 minutes. If you don't measure enough bromine, add more bleach. If it's used up very quickly, then go ahead and shock with three times as much bleach -- 9 fluid ounces. If that still doesn't hold, then I would suggest you get the Ahh-Some and use it and then dump/refill. You might have some serious biofilms in your plumbing and Swirl Away isn't nearly as good as Ahh-Some at getting rid of it.

Also, if you haven't cleaned your filter in a while, you should take a look at it and clean it if it's dirty.

OK, thank you. I just put 3 oz. in. We put clean filters in when we refilled it a couple days ago. I told my husband what you said about possibly having to dump and start over again and he said "I'm returning it if that's the case." HAHA!

I will keep you updated. (I'm sure you are just waiting on the edge of your seat.)
 
Yup. I'm just worried that you've got a somewhat permanent demand in the pipes. The only other option if that occurs other than using the Ahh-Some with drain/refill would be to try and superchlorinate but that's not always as effective and usually you drain/refill after that as well (though we can dechlorinate instead). I hope this isn't necessary and that you break through whatever is consuming the bromine. Bring it up to 12 ppm by adding around 7 fluid ounces of bleach.
 
Yup. I'm just worried that you've got a somewhat permanent demand in the pipes. The only other option if that occurs other than using the Ahh-Some with drain/refill would be to try and superchlorinate but that's not always as effective and usually you drain/refill after that as well (though we can dechlorinate instead). I hope this isn't necessary and that you break through whatever is consuming the bromine. Bring it up to 12 ppm by adding around 7 fluid ounces of bleach.

Well, it is now at 5. Should I just go by PoolMath and add whatever that says to get it to 12? It says 4.6 more oz of bleach at my calculations.

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Oh, I added 3 oz the second time. I did it before I saw your reply. Then, I waited 30 minutes and tested and got 5.
 
Up to you. You just need to see if it continues to drop too quickly. If it does, then raise it up higher. If not, then you're good. From 5 ppm it shouldn't drop too much below 4 over 24 hours -- if it's 3 or below then you've got higher than normal demand. If you're willing to just live with that (for a while until your next water change) and keep dosing to keep it up, then you can do that.
 
It is covered, but it has NOT been covered today as I have been testing and putting in chemicals so much. Normally, it is closed all the time except when being used. We normally only use it in the evenings when it is mostly in the shade. Does that make a difference? My husband asked me earlier if that would change anything. I can close it between things, but I was afraid I was going to wear out the cover!
 

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