Using MPS and Dichlor at the same time?

[NorthWoodsDipper]

My Arctic information says to shock with BOTH MPS and Dichlor (per my spa size, I am told to use 1oz of Dichlor and 2oz of MPS).  All I read in this forum talks about using either / or, but not both at the same time.  What do you all think?  Also, one document I have from them states to add them both at the same time, but the other says to add the MPS, let it run for 30 mins and then add the Dichlor and let it run again.  Is this a better idea than adding both at the same time?

Steven-

[Chad]

They make an enhanced mps that has dichlor already in it, so I would think it's ok.
I sometimes add them both at the same time as well. I'm not sure if it's "better" to just add one at a time or not.

[svspa]

NWD,

They may be suggesting you are really shocking with the MPS and super sanitizing with the dichlor.

Normally I think most folks would use either an all dichlor routine (use dichlor for their daily sanitizer and their shock dose) or a hybrid (use dichlor for their daily sanitizer and MPS for their shock).

There are +/- with either approach.

All dichlor is cheap. Insures you are super sanitizing your tub (with your shock dose). Downside is you have to be sure you reach breakpoint chlorination to oxidize the combined chlorines out. Another downside is you have to wait until your free chlorine level comes back to somewhat normal before tubbing.

Using MPS for your shock is a bit easier, no need to figure out how much you need to oxidize the combined chlorines. Whatever amount you add will oxidize what it can. You can be tubbing within 30 minutes of an MPS shock. But MPS adds to your total dissolved solids faster than dichlor and it is a bit more expensive.

If you go with the MPS shock routine you could substitute a dichlor shock every once in a while so you get the super sanitizing effect of the dichlor shock. Or as they suggest do both every once in a while, just to get that super sanitizing effect.

I don't think there is any issue with doing them both at the same time.

Steve

[Vinny]

I've used both dichlor and MPS but not to shock with both.

Usually I will shock with MPS and if the tub hadn't been treated with dichlor in a couple of days, I'll add dichlor after a 20 miute MPS cycle.

[tony]

I also use both.  Like Vinny, I shock with MPS.  Because I use a minimal amount of dichlor after each use (enough to reach 2ppm), I like to add enough dichlor weekly to get to 5 ppm.  I don't necessrily shock every week but on those weeks that I do, I add both at the same time.

[windsurfdog]

Ditto exactly, Tony.  This a.m. after soaking, I added 2 tsp. dichlor and 2 tbsp. MPS and let all pumps run for 15 min. and left the cover open for another 5-10 min., closed it up and now it's ready for the next soak...easy!

[In Canada eh]

I use the same approach as Vinny,Windsurfdog and Tony,  dichlor after each use, shock with MPS and about once every two weeks shock dose of dichlor.  Remember to leave the cover open after shocking as Windsurfdog said.

[anne]

I pretty much use the same protocol.......1-2 tsp dichlor after each use, and generally MPS to shock with an occasional dichlor shock if I can handle not using the tub for a few days. Canada.....I'm a little puzzled.....you said "shock with MPS and about once every two weeks shock dose of dichlor." How often are you shocking with MPS if you are also shocking every other week with dichlor? I only shock the tub, whether it be dichlor or MPS, a max of every other week.

[In Canada eh]

I pretty much use the same protocol.......1-2 tsp dichlor after each use, and generally MPS to shock with an occasional dichlor shock if I can handle not using the tub for a few days. Canada.....I'm a little puzzled.....you said "shock with MPS and about once every two weeks shock dose of dichlor." How often are you shocking with MPS if you are also shocking every other week with dichlor? I only shock the tub, whether it be dichlor or MPS, a max of every other week.

Anne,

    I shock my tub on a schedule (every Thursday evening)I have found it easier to follow a schedule then to perform a test.  I know its probably overkill but it works for me  Every two or three weeks I will shock with a higher dose of dichlor, not so much for the shock but more for the super sanitation.  I like the idea of giving the tub a good blast of chlorine once in a while.  It may not be the right or most efficient way to do things but it works for me, other then the goofy pH and alkalinity mentioned in the other thread my water is normally well behaved.

[anne]

That makes sense. I think the only issues of using MPS too frequently would be 1) it'll lower pH (not a problem in your case!) and 2) faster accumulation of TDS, which may not matter if you dump and refill on a frequent enough basis.

[Reese]

My Arctic information says to shock with BOTH MPS and Dichlor (per my spa size, I am told to use 1oz of Dichlor and 2oz of MPS).  All I read in this forum talks about using either / or, but not both at the same time.  What do you all think?  Also, one document I have from them states to add them both at the same time, but the other says to add the MPS, let it run for 30 mins and then add the Dichlor and let it run again.  Is this a better idea than adding both at the same time?

As someone mentioned, there are enhanced shock products that contain both, so applying together is no problem.

I once read an argument for applying MPS first.  The theory was that chlorine is a stronger oxidizer, so if applied together, the chlorine would get used up oxidizing organics, rather than sanitizing, while the MPS would be left with nothing to do until more organics are introduced.  According to that paper, if you put the MPS in first, it will do the oxidizing, leaving the chlorine free to sanitize.

[tony]

As someone mentioned, there are enhanced shock products that contain both, so applying together is no problem.

I once read an argument for applying MPS first.  The theory was that chlorine is a stronger oxidizer, so if applied together, the chlorine would get used up oxidizing organics, rather than sanitizing, while the MPS would be left with nothing to do until more organics are introduced.  According to that paper, if you put the MPS in first, it will do the oxidizing, leaving the chlorine free to sanitize.

That makes a lot of sense.  I wonder if you have to wait a period of time for the MPS to complete oxidizing.

[Reese]

That makes a lot of sense.  I wonder if you have to wait a period of time for the MPS to complete oxidizing.

I don't remember where I saw the article I referenced. I would imagine it needs some lead time, but I don't know how long.  Based on the original post, it seems Arctic thinks 30 min.  I personally just add MPS, let it run for 1 jet cycle (15 min), then add the dichlor.  I figure some head start is better than nothing, and 30 minutes seems to be the outside edge of my ability to remember to go back and shut the cover.  

[windsurfdog]

As someone mentioned, there are enhanced shock products that contain both, so applying together is no problem.

I once read an argument for applying MPS first.  The theory was that chlorine is a stronger oxidizer, so if applied together, the chlorine would get used up oxidizing organics, rather than sanitizing, while the MPS would be left with nothing to do until more organics are introduced.  According to that paper, if you put the MPS in first, it will do the oxidizing, leaving the chlorine free to sanitize.

I would think that makes sense IF you dose enough chlorine to hit the breakpoint.  If your dichlor dose is under the breakpoint, I would think the dichlor would contribute solely to sanitization while the shocking would be left for the MPS.

This is very interesting, Reese.  Thanks for finding that tidbit of info.  I look forward to continued comments.

[NorthWoodsDipper]

As someone mentioned, there are enhanced shock products that contain both, so applying together is no problem.

I once read an argument for applying MPS first.  The theory was that chlorine is a stronger oxidizer, so if applied together, the chlorine would get used up oxidizing organics, rather than sanitizing, while the MPS would be left with nothing to do until more organics are introduced.  According to that paper, if you put the MPS in first, it will do the oxidizing, leaving the chlorine free to sanitize.

Reese,  That was my point exactly.  Even though I don't understand the Chemical stuff too much (newbie since Oct 06), it just made sense to super sanitize AFTER I let the MPS do the shocking.  But then again, why even use MPS if I am using 1 oz of dichlor anyway?  Won't 1 oz of dichlor take care of the shocking on a 500 ga spa?

On a side note, WHEN do you need to super sanitize?  After reading this forum, I am thinking about shocking every other time with MPS only.  If I do that, and then shock with the combination recommended by Arctic, or possibly just dichlor, is there a need to super sanitize besides that?

So if I continue with the MPS+Dicholr shock, does anyone have input as to how long to wait to add Dichlor?

Oh, and FYI, my water has always been great.  But like I said, I have only had my Arctic since Oct 06.

Steven-