New Owner - Chemicals questions....

[chem geek]

Both Spa Marvel and Spa Solution are enzymes.  They help to oxidize some chemicals in bather waste using oxygen in the water.  They will not prevent biofilms nor are they disinfectants so will not kill bacteria.  As for the MSDS for Aquafinesse, it will not list all chemicals since the surfactants are not considered hazardous to health (i.e. not related to material safety).

Why are you all so focussed on these extra products that are not necessary for proper disinfection nor oxidation in a spa?  Chlorine alone is all that is needed, but needs to be maintained consistently and enough needs to be added after each soak to be enough to oxidize bather waste.  If one has an ozonator, then ozone can oxidize some of the bather waste so that you need less chlorine after each soak (though will need more in between soaks because ozone reacts with chlorine).  If you want a (mostly) non-chlorine system, you can use Nature² with its silver ions and use non-chlorine shock (MPS) as the oxidizer and is also a disinfectant in the presence of silver ions at hot water temperatures (and is EPA approved as a disinfectant because of this).  You can use chlorine on occasion to keep the water clear.

[Gibson00]

I was focused on it because my dealer told me I was supposed to use it!  I'm very relieved to find out I don't really need to! 
So, right now I am using spa tabs, which my understanding are chlorine tablets.  I looked closely at the spa tab bottle, and it doesn't seem to say which type of chlorine it is.
This is the product:
http://www.hottubchemicals.ca/spaboss-spa-tabs/

I was told to add one every three days.  After one week, the chlorine levels seem to be pretty stable, within the range on the test strips.  But is this not a good chlorine product to use?  Should I be using the granular dichlor crystals instead?  If yes, how much and how often would I add them to a 500 gallon tub, used 20 minutes a day by 3 people??

Thx!

[Vinny]

On the back of the bottle it should say what type of active ingredients it has. It does sound from the description on that website that it is trichlor due to the fact it mentions it will lower pH and alkalinity, dichlor is usually advertised as pH neutral.

The question of how much granular chlorine to use depends on you. For an empty 500 gallon tub you may need 2 1/2 tablespoons to get to 3 ppm chlorine. With 3 showered people maybe 3 1/2 to 4; after sweating all day it may be 5. I always add a little extra chlorine whenever I have people in my tub vs soaking alone. For just me with a 400 gallon tub I add 2 tablespoons of granular chlorine for 3 ppm. When my wife soaks with me I add another because she uses lotions and all, if more people I add another ... This will bring me up to 6 or more ppm to use as a disinfectant and oxidizer. I also super chlorinate every so often to about 10 ppm for good measure.

[Dr. Spa™ Ret.]

Blow up the pic and it says trichlor.

[chem geek]

Trichlor tabs aren't usually used in hot tubs because in hot water the Trichlor tends to dissolve too quickly so at a minimum you need a special feeder that can be dialed down considerably (there are some combo bromine/chlorine feeders that can do this).  Trichlor is also quite acidic so will tend to lower the pH and also consumes (lowers) TA so you have to add baking soda to raise the TA or use a pH Up product to raise both pH and TA.  If you use the Trichlor, then I'd suggest dialing it down to only provide a background dose of chlorine between soaks so maintaining say 2 ppm FC.  That will lessen the effects from the Trichlor.  Note that if the feeder parks itself in one area of the spa, the acidity of the Trichlor may damage the acrylic or metal (if any from jets) nearby.  This is especially true if the spa does not have 24 hour circulation.

After each soak, you'll need to add additional disinfectant and could use the Dichlor-then-bleach method for that though probably stop using Dichlor when you get to 20 ppm since Trichlor will keep increasing the Cyanuric Acid (CYA) level over time.  Since the Trichlor is acidic, the use of bleach may work out well in terms of pH.  You should then maintain the TA at a level where the pH tends to be somewhat stable -- if the pH tends to rise then the TA can be lower (though not below 50 ppm) and if the pH tends to drop then the TA can be higher (but probably not above 100 ppm).  If the pH tends to rise or if you are targeting a low TA, then I'd use 50 ppm Borates (from boric acid).

As for how much additional chlorine to add after each soak, it depends on your bather load and whether you have an ozonator.  A rough rule-of-thumb with no ozonator is that every person-hour of soaking in a hot (104ºF) spa requires roughly 3-1/2 teaspoons of Dichlor or 3-1/2 fluid ounces of 8.25% bleach (or 7 teaspoons of non-chlorine shock, 43% MPS, but that's normally when using Nature²).  With an ozonator, you may only need half these amounts or less.  The real rule is to add whatever is necessary to still have a residual of chlorine 24 hours later.

[Vinny]

Blow up the pic and it says trichlor.

I tried this morning on my tablet and the photo was acting funky. As much as I blew it up it kept wanting to stay "centered" on the website and it wouldn't let me scroll ... it happens every now and then.

Great minds think alike! I'm sorry for you!

[Gibson00]

Thanks for the info.  Right now They just have me putting the spa tablet in a little screw top holder that is just big enough to fit the tablet, and they have me put it in under one of the filters (Arctic Spa).  The tablet is mostly dissolved after about 3 days.  Just using the test strips, the chlorine does seem to be staying pretty stable.  I did have to add a small amount of baking soda the other day, thats about it.

Oh, no ozonator on mine, and it is 500 gallons (Arctic Summit).