SODIUM THIOSULFATE Chlorine damages and can kill your fish! If you add any water
to your pond, you need to dechlorinate. If your water contains only chlorine, then sodium
thiosulfate is an excellent and inexpensive dechlorinator. Remember, always dechlorinate tap
water, whether you're replacing 1000 gallons or just 5 gallons.
CAUTION May be harmful if swallowed or inhaled. May cause irritation to skin, eyes and
respiratory tract. The description of sodium thiosulfate pentahydrate in the Aquatic Eco-Systems
catalogue states, "Excess levels up to 100 PPM will not harm fish". Double doses can be used for
chloramines, but note that Sodium Thiosulphate will only neutralize the chlorine ion and not the
ammonia molecule.
DOSAGE To completely dechlorinate water, it is necessary to use 0.74mg/L of Sodium
Thiosulfate for each 1mg/L (1PPM) of Chlorine. A stock solution should be prepared. A sodium
thiosulfate stock solution is a quantity of water and sodium thiosulfate of which we know that x
amount will treat y amount of water containing z amount of chlorine.
PROCEDURE Prepare a stock solution of 190gm (3/4 cup) sodium thiosulfate in 1/2 gallon
distilled water. This is a 10% solution.
If you have 1PPM Chlorine ADD
1/8 cup (30ml) stock solution to 1000 gallons (about 3gm active ingredient)
1/4 cup (160ml) stock solution to 2000 gallons (about 6gm active ingredient)
1/2 cups (120 ml) stock solution to 4000gallons (about 12gm active ingredient)
If you have 2PPM Chlorine ADD
1./4 cup (160ml) stock solution to 1000 gallons (about 6gm active ingredient)
1/2 cup (120ml) stock solution to 2000 gallons (about 12 gm active ingredient)
STORAGE Sodium Thiosulfate dechlorinator should be stored indoors in a cool, dry place
that is inaccessible by both children and pets. A STOCK SOLUTION has a shelf life of about 6
months. Sodium Thiosulfate crystals lasts several years.
HANDY CONVERSIONS
Liquid
Dry
1 gal
= 3.785 liters
1 lbs = 453.6 gm
= 16 cups
= 16 oz
= 128 fl oz
1 oz = 28.35 gm
= 4 qts
1 liter = 1000 ml
1gm = 1000 mg
1 gallon water = 8.4 lbs = 3,810 gm