Shock Amount?

[ncspa]

I use MPS to shock about twice per week (using tub 1-2 times per day). The container tells me to use 3oz for my 350-gal. tub. However, that seems to take my bromine sky high. If the water remains clear, is there any reason I couldn't just use less (say 1 or 2 oz)? Is there an easy way to gauge the correct frequency and amount of shock?

[watersentinel]

I use MPS to shock about twice per week (using tub 1-2 times per day). The container tells me to use 3oz for my 350-gal. tub. However, that seems to take my bromine sky high. If the water remains clear, is there any reason I couldn't just use less (say 1 or 2 oz)? Is there an easy way to gauge the correct frequency and amount of shock?

Shocking your spa with mps or dichlor is going to do the same thing. Both are reactivating the bromine in your spa which is why your bromine goes sky high. Yes, you can add less. The only thing you are doing by adding mps or dichlor to a bromine spa is quickly raising the bromine level. If your bromine dispenser is not keeping up with the demands to maintain 3-5 ppm bromine or there was heavy use of the spa, then add just enough mps to get to that level. When shocking add a little at a time. You can't take it out once it's in there. Add it in increments until you reach the 5-10 ppm range.

[ncspa]

I use MPS to shock about twice per week (using tub 1-2 times per day). The container tells me to use 3oz for my 350-gal. tub. However, that seems to take my bromine sky high. If the water remains clear, is there any reason I couldn't just use less (say 1 or 2 oz)? Is there an easy way to gauge the correct frequency and amount of shock?

Shocking your spa with mps or dichlor is going to do the same thing. Both are reactivating the bromine in your spa which is why your bromine goes sky high. Yes, you can add less. The only thing you are doing by adding mps or dichlor to a bromine spa is quickly raising the bromine level. If your bromine dispenser is not keeping up with the demands to maintain 3-5 ppm bromine or there was heavy use of the spa, then add just enough mps to get to that level. When shocking add a little at a time. You can't take it out once it's in there. Add it in increments until you reach the 5-10 ppm range.

Actually, I try to keep the bromine closer to 1-2ppm - running an ozonator, that is apparently sufficient. My floater does a great job of keeping it at that level. I continue to use the shock, however, to eliminate the bacteria that the sanitizer has killed. I simply want to make sure I'm accomplishing that. I assume that cloudy water would indicate that not enough is being used....

[watersentinel]

Whatever level you choose to keep your bromine level at the advice about shocking is the same. I've seen what happens with low sanitizer levels so I tend to be conservative. If it's working for you, that's great. Shocking once a week is usually enough to burn off waste in your water. If you have high bather loads or heavy use, then twice a week might be needed. Just experiment to see how much mps you need. The level that your bromine is raised to is more important than the amount of product you add. Don't forget that an ozonator aids in the removal of the waste in your spa, so you might not need as much shocking as you think you do. If your bromine level is ever too high you can try opening your cover and running the jets. The fact that your bromine is skyrocketing after a shock shows that you are adding more than enough mps. MPS will oxidize waste in the spa and the excess will be converted to bromide. So don't worry that you aren't adding enough. Shocking with bromine is not the same as shocking with chlorine where you need to reach a breakpoint. As a side note, cloudy water is an indicator that things are off in the spa but not the only indicator. Clear water does not mean healthy water.

[ncspa]

Just experiment to see how much mps you need.

You just hit the question right there! How do you figure how much mps you need? I guess that's the way I should have stated this from the beginning, but that's what I'm after.

[watersentinel]

Nc you said that at 3oz of mps your bromine went through the roof. How high did it go? You could try adding 1oz and testing and continue adding 1oz until you reach the desired bromine level. If 1 ounce increments are too much then try 1/2 ounce at a time. 5-10ppm is the suggested range for a shock.

[chem geek]

Nc you said that at 3oz of mps your bromine went through the roof. How high did it go? You could try adding 1oz and testing and continue adding 1oz until you reach the desired bromine level. If 1 ounce increments are too much then try 1/2 ounce at a time. 5-10ppm is the suggested range for a shock.

Roughly speaking, 1 teaspoon of MPS in 350 gallons is equivalent to 1 ppm FC so would activate about 2 ppm Bromine. Of course, if there are other things in the water to oxidize, then more MPS would be needed.

3 ounces weight of MPS in 350 gallons would be equivalent to around 13 ppm FC so would activate about 26 ppm Bromine.

[ncspa]

Nc you said that at 3oz of mps your bromine went through the roof. How high did it go? You could try adding 1oz and testing and continue adding 1oz until you reach the desired bromine level. If 1 ounce increments are too much then try 1/2 ounce at a time. 5-10ppm is the suggested range for a shock.

Roughly speaking, 1 teaspoon of MPS in 350 gallons is equivalent to 1 ppm FC so would activate about 2 ppm Bromine. Of course, if there are other things in the water to oxidize, then more MPS would be needed.

3 ounces weight of MPS in 350 gallons would be equivalent to around 13 ppm FC so would activate about 26 ppm Bromine.

Ahh....that's what I was looking for! Thanks.