Pros/cons using Dichlor or MPS

[Sjde]

I realize even a bromine spa has some chlorine in it (due to the bromine tabs).
Is there a preference for using dichor as an activator/shock over MPS?
If it was a home spa I might use bleach, but this is at a vacation rental. I'd like to leave some product for the guests to put in after each use, with instructions.

So is one more simple for them to use , or not as critical if they were to mess up and put too much in?


Does one affect the pH or alkalinity more than the other?

 

[JoyfulNoise]

Both MPS and dichlor can convert the bromide to bromine but MPS takes a little longer than chlorine to reactivate the bromine. MPS is not as effective as chlorine in oxidizing certain kinds of bather waste so if the renters were to use the tub heavily during their stay and not know how to test, then the chloramines/bromamines may build up to a higher, more detectable level (odor). Both will lower pH and TA.

So it kind of depends on how much bather load you expect. With instructions about how much to add, you should also leave instructions for how to turn the tub on and how long to wait between soaks in the tub after adding chemicals since the initial bromine levels after adding oxidizer can get quite high. You could even leave a simple Bromine/pH tester with instructions on how to use it and what levels are considered "safe". You should also leave some baking soda to add to help bump up the pH in case it gets too low. The baking soda will add to the TA and then the aeration from the spa jets will help to slowly raise the pH. I would rather that then using something like pH-Up (soda ash) because they could easily drive the pH up too fast. Baking soda is a slower alternative method for a hot tub.

It's sort of a trial and error process since some renters may not use the tub at all and others may avail themselves of it at every opportunity. So you'll just have to see how much "damage" is done when you get there. I would also keep a good amount of Ahh-Some on hand because I, for one, would be totally grossed out thinking about soaking in a hot tub where other people have "used" it. My first order of business would be an Ahh-some flush and dump of the existing water and then a fresh refill for myself...

 

[pooldv]

I would say that bleach would be the simplest and cheapest product to use. Plain, generic, store brand, concentrated, unscented from the grocery store or big box store. Virtually no impact to pH/TA and no CYA.

 

[Sjde]

How is Ahh-some used? Added to the spa, emptied and refilled?

 

[pooldv]

Yes, add it, run it to flush the pipes, drain it and refill.

 

[JoyfulNoise]

How is Ahh-some used? Added to the spa, emptied and refilled?

Ahh-Some Water Cleanser for Your Pool, Hut Tub, Jet Bath, Swim Spa and Washing Machine -

 

[Sjde]

It seems like those with a bromine spa might want to stay away from bleach, or even dichlor?

 

[Sjde]

I thought with Ahh-some you had to drain and fill twice.

 

[JoyfulNoise]

I thought with Ahh-some you had to drain and fill twice.

It depends on how good you are at cleaning all the scum off. After it runs and you develop the scum/foam layer, you drain the tub. While it's draining you should rinse the walls down and wipe them to get rid of any scum from the lines. Some people will then use their shopvacs to suck the water out of the jets. Then, when you refill, you may need to run at higher FC levels to break down any residual Ahh-some left. Rinsing it out while it drains will take out most of the Ahh-some.

 

[Sjde]

Hmmm, I don't check FC. Don't need to in a bromine spa.

 

[JoyfulNoise]

Hmmm, I don't check FC. Don't need to in a bromine spa.

You check bromine though...so you might need higher (shock) levels of bromine to kill off the last little bit of Ahh-some.

Just for clarification, your test kit, no matter which one you use, really measures the concentration of all halogen oxidizers in the water - chlorine, bromine, iodine. Since iodine is not present, when you add chlorine to a bromine spa and measure right away with the DPD test, you are measuring some combination of chlorine and bromine. They both turn the DPD pink and the FAS titrant reacts the same way with both. The only difference is that you multiply the drop count by different factors to determine either chlorine or bromine levels. This is why adding bromine to a swimming pool for algae control is so problematic - there's no way to distinguish (easily) bromine from chlorine.

 

[Brian VT]

It seems like those with a bromine spa might want to stay away from bleach, or even dichlor?

Why do you say that?