I just dug this up in literally 4 secs.
And it doesnt seem to come in 250g jars, as well as having different measurements for removing the different things. It doesnt actually make sense since it seems a treatment for chlorine, would be effective for everything else since chlorine requires the strongest dose.
http://www.seachem.com/products/product_pages/Safe.html
Safe™ is the complete and concentrated conditioner for both fresh and salt water. Safe™ removes chlorine, chloramine and ammonia. Safe™ converts ammonia into a safe, non-toxic form that is readily removed by the tank’s biofilter. Safe™ may be used during tank cycling to alleviate ammonia/nitrite toxicity. Safe™ detoxifies nitrite and nitrate, allowing the biofilter to more efficiently remove them. Safe™ is non-acidic and will not impact pH. Safe™ will not overactivate skimmers. Use at start-up and whenever adding or replacing water.
Sizes: 10 g, 50 g
DIRECTIONS: To remove…
• Chlorine: use 1 measure to each 60 L (15 gallons*) of tap water (removes 1 ppm).
• Chloramine: use 1 measure to each 75 L (20 gallons*) of tap water (removes 1 ppm).
• Ammonia: use 1 measure to each 11 L (3 gallons*) of tap water (removes 1 ppm). Do not overdose!
For reference, 1 measure = 100 mg. To detoxify nitrite/nitrate in an emergency situation use up to 5 measures to each 40 L (10 gallons*). Use fish to gauge toxicity reduction as test kits will still show presence of nitrite/nitrate even when detoxified. May be added to aquarium directly, but is better if added to new water first. If adding directly to aquarium, base dose on aquarium volume. If temperature is > 30 C (86 F) cut dosing in half.