Nitro's Method - How Much To Buy?

[Lord Bodak]

I'm putting together my first big order for supplies for my tub. I have to order filters anyway (the tub has been dormant for a while since the old owner moved out of the home), so I'm going to order chemicals online too to save money. I'm leaning towards trying Nitro's method first, although I suspect I will also try bromine down the road.

I'm trying to get a feel for what quantities I should be ordering at this point. Spa Depot sells dichlor in 1, 2, and 5 pound containers. Nitro also mentioned using MPS occasionally so I want to order some of that as well; would a 2 pound container be enough to start with?

For bromine I have the same questions: how many pounds of sodium bromide and bromine tablets would I want to have on hand when it comes time to try that?

EDIT: The tub is approximately 300 gallons.

Edited July 14, 2010 by Lord Bodak

[chem geek]

The following assumes there is no ozonator. With an ozonator, the amount of bleach and non-chlorine shock (MPS) needed would be less -- probably half as much if you use the tub every day.

With your 300 gallon tub, you would use around 2.4 ounces weight (about 5 tablespoons) of Dichlor during the first week or so to build up to 30 ppm CYA. After that you would use about 5 fluid ounces of 6% bleach for every person-hour of soaking. You would also add around 0.4 ounces weight (about 2-1/2 teaspoons) of Dichlor every month to replenish around 5 ppm CYA. As for non-chlorine shock (MPS), this is optional, but figure around 1-1/3 ounces weight or around 2 tablespoons per week. So you can see that you won't need to get very much Dichlor nor MPS since there are 16 ounces in a pound. So get the smallest container of Dichlor, so 1 pound, and probably 2 pounds of MPS should be fine. However, since the MPS will register as CC and isn't really necessary, you might opt for 1 pound instead and see how things go.

So the largest consumable is the bleach where one person-hour of soaking every day would be around 1-1/2 3/4-gallon (96 fluid ounce) jugs of 6% Clorox regular unscented bleach per month.

[quantumchromodynamics]

On start-up of a bromine tub, you want to establish a bromide bank of 30 ppm bromide ions. To do this, you will need 15 grams per 100 gallons of tub water. For a 500 gallon tub, you would add 75 grams of sodium bromide. If you got a 1-pound bottle of sodium bromide, that would do six fills of a 500 gallon tub. A two pound bottle of bromine tabs should be sufficient for a while.

Gallons....................Sodium bromide salt needed to add 30-ppm bromide ion concentration.

100.........................15 grams (0.53 ounces)

200.........................30 grams (1.1 ounces)

300.........................45 grams (1.6 ounces)

400.........................60 grams (2.1 ounces)

500.........................75 grams (2.6 ounces)

You can use bleach or MPS to oxidize the bromide to bromine. A 3 quart bottle of bleach would last you a while. You could use MPS if you wanted. A one or two pound bottle should be sufficient to get you started.

[Lord Bodak]

Thanks for the answers! This forum looks like an incredible resource and I think I'll be spending a lot of time here!