11-30-2014, 07:51 AM
Join Date: Mar 2008
Location: Seattle, WA
iTrader Positive Rating: 100%
| | Re: Sodium Thiosulphate
+1 for Michael's comment, sodium thiosulfate does not remove chloramines that are being used by many water utilities today. It also changes the PH of the water. The original Water-Rite product (now changed) used for decades during the 1950's, 60's and 70's by hobbyists was basically a buffered sodium thiosulfate product (because sodium thiosulfate can change water PH). As utilities had more difficulty killing the bacteria in our water supplies they started adding chloramines in addition to chlorine.
Chloramine is a chemical used to disinfect water. It is ammonia (NH3) bonded to chlorine. It resists breaking down and is used because of its stability in water. Sodium thiosulfate on its own, can be used to remove the chlorine, but when used alone ammonia is left over. The toxicity of ammonia will depends on a few factors. This article should help you decide the best course of action in your situation. Ammonia is not toxic at a pH below 7.0. This happens because in acid conditions, free hydrogen ions convert it to ammonium NH4. As pH rises above 7.0, these hydrogen ions are less available, leaving more toxic ammonia (NH3).
I used Water-Rite back in the day (I'm in my 60's), now I use Seachem Prime. it removes both chlorine and chloramines and chemically binds any ammonia making it non-toxic to my fish. Two drops per gallon (5 ml / 1 teaspoon per 10 gallons) is all it takes.
Prime® also contains a binder which renders ammonia, nitrite, and nitrate non-toxic. It is very important to understand how those two functions work together. All dechlorinators operate through a chemical process known as reduction. In this process, toxic dissolved chlorine gas (Cl2) is converted into non-toxic chloride ions (Cl-). The reduction process also breaks the bonds between chlorine and nitrogen atoms in the chloramine molecule (NH2Cl), freeing the chlorine atoms and replacing them with hydrogen (H) to create ammonia (NH3). Typically, dechlorinators stop there, leaving an aquarium full of toxic ammonia! Seachem takes the necessary next step by including an ammonia binder to detoxify the ammonia produced in the reduction process.