There are may different types of deck stain strippers. In general, all stripper and stain removers for decks are biodegradable. The majority of stripper will contain the active ingredient of a well know caustic called sodium hydroxide. There are two different ways to buy a deck stripper. In a liquid ready mix formula or in a powdered formula.
Powdered Deck Stain Strippers
Powdered wood and deck stain strippers are very effective and considerably less costly than pre-packaged liquids. The normally mix at about 8oz of powders to 1 gallon of water. For example, a $30 container of Restore-A-Deck Stain Stripper will make 5 liquid gallons. That is a cost of about $6 per gallon. In addition, a powder stripper can be mixed at different ratios. Less so for easier to remove coatings and more for those difficult to remove stains. The negative is that you will need to be extra careful when mixing. Best to use rubber gloves, protective eyewear, and clothes.
Pre-mixed Liquid Stain Strippers
Deck Stain strippers that come pre-mixed are easier to use in that they are ready to apply right our of the bottle. No mixing or measuring is required. Negative is that they cost 3-4 times as much then a powdered deck stripper.
All stain stripper will raise the pH balance of the wood due to the active caustic ingredients. They require a wood brightener to neutralize and lower the pH balance for optimal stain performance.