Newb User...newb Tub

[wepham]

Good morning all,

I come to you in need of assistance. I know I probably didn't do some things 'correctly'; upon startup, so don't flame me for that...but I just want to get things straight in my new tub.

I got a South Seas 735L last week..I love it. 360 gallons.

So, I started the tub off with Spa Essentials Brominating Concentrate. I put in 1 3/4 teaspoons as per the instructions, waited 20 minutes as per the instructions, tested, and everything looked great. PH was normal, Alkalinity was low (added a little baking soda to come up, then it was normal), hardness was a low. Bromine was measuring at about 4.5 ppl. I have 4 bromine pucks floating in a floater.

So we went in last nite...3 of us for about 3 hours... When we got out I put in some MPS shock because I figured it was a good idea. Closed the cover..ran the pumps overnight, went to bed.

I woke up this morning, tested the water, bromine is non-existant on test strip. Pure white.

I read the Spa Essentials concentrate label and it said that it may be necessary to shock with it after a heavy bather load. So, I added the recommended dose (about 6 tsp) this morning, and my bromine is now measuring well, a little high actually, at about 10.

My question is.... is this normal? Are the pucks doing nothing? Do I have another issue?

Thanks in advance. I really am trying to get a hold on all of this and I would appreciate some help

[chem geek]

When you soak, this will use a substantial amount of disinfectant/oxidizer. Usually the pucks in a floater are for maintaining a background level of bromine. You usually need to add an oxidizer after your soak, especially if it's a high bather-load such as you described with 3 people for 3 hours. I presume that was not at 104ºF since you cannot soak that long at that temperature, but if it was still hot then figure the equivalent of 5 or so person-hours and that would normally require a LOT of oxidizer. Do you have an ozonator? If you do, then the amounts I describe might be cut in half; if not, then for every person-hour of soaking in a hot spa it requires around 3-1/2 teaspoons of Dichlor, 3-1/2 fluid ounces of 8.25% bleach, or 7 teaspoons of non-chlorine shock (43% MPS). If we assume 5 person-hours, then that would be 35 teaspoons or nearly 6 ounces of non-chlorine shock. I suspect you didn't put in even close to that amount. Every person-hour would need roughly 1/2 ounce of the brominating concentrate (BCDMH) but I don't know it's density in granular form for that product. If I assume it's near 1 g/ml (solid BCDMH is 1.9 g/ml), then that's 1 tablespoon or 3 teaspoons. You put in 6 so enough to handle 2 person-hours. [EDIT] WRONG! I mistakenly looked at the MSDS for tabs, not granular -- the actual product is 82.5% Dichlor so use 3 teaspoons per person-hour which ironically is the same as I calculated by coincidence. [END-EDIT] The MPS shock probably handled some more.

So yes, what you experienced is normal, but you need to add more oxidizer right after your soak and not wait. You should get some feel for how much you need to add and relate this to the person-hours of soaking so that you can know how much to dose in the future. You want to add enough after your soak so that you still measure a residual 24 hours later.

[wepham]

Thanks for the response!

You said 3 1/2 diclor or bleach per person hour..then you mentioned 1/2 ounce brominating concentrate per person hour... these are interchangable statements correct? You dont mean 3 1/2 diclor AND 1/2 once brom concentrate?

BTW..Spa Essentials Brominating concentrate = 82.5% Sodium dichloro-s-triazinetrione, 14.7% Sodium bromide.

Getting ready to go dump some bleach in the tub

[chem geek]

Yes, there are OR, not AND. You can use any oxidizer you like in a bromine spa because you have a bromide bank from which more bromine can be created by adding an oxidizer.

Thanks for correcting me on the Spa Essentials Brominating concentrate. I was incorrectly using an MSDS on tabs, not powder. Since the concentrate is mostly Dichlor, you should use the Dichlor amount times 82.5% so that's roughly 3 teaspoons of concentrate per person-hour (which coincidentally is the same as I calculated before even though I assumed the wrong chemical). Sorry for any confusion this may have caused.