I think it would best for some folks to review this past thread of mine.
Cost Effective Water Conditioners | MonsterFishKeepers.com
My formula in that sticky linked to above should not be that difficult, once you know what the low & high disinfectant residual is in your local tap water. Mine is pretty close to 2 ppm year round, during spring run off, heavy storms, I add a bit extra as it can swing closer to 2.5 ppm. (chloramine)
You do NOT want to be overdosing by 5 times the amount! Not ever, and Seachem dumbed down their entire product line of water conditioners because their consumer base was indeed overdosing. I know that for a fact, as the CEO of Seachem told me exactly that. You can read more about that in this past topic.
The Dumbing Down of Seachem | MonsterFishKeepers.com
Some simple math, from my sticky. Use your own disinfectant type (chlorine or chloramine) and amount in mg/l or ppm (same thing) to get your magic number. Ignore their current labels, the dumbing down topic explains why.
My 4kg container states for chloramine, 5 g (1 teaspoon) to each 950l (250 gallons) of tap water (4ppm) ........ now Seachem has upped that value to 5 g (1 tsp.*) to each 1250 L (300 gallons - actually works out to 329 gallons*) of tap water (removes 4 ppm).
Directions for 10 g and 50 g
To remove
Chlorine: use 1 measure to each 130 L (35 gallons*) of tap water (removes 1 ppm)..
Chloramine: use 1 measure to each 100 L (25 gallons*) of tap water (removes 1 ppm).
Ammonia: use 1 measure to each 32 L (8 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.
Directions for 250 g and larger
To remove
Chlorine: use 5 g (1 tsp.*) to each 1625 L (450 gallons*) of tap water (removes 4 ppm).
Chloramine: use 5 g (1 tsp.*) to each 1250 L (300 gallons*) of tap water (removes 4 ppm).
Ammonia: use 5 g (1 tsp.*) to each 400 L (100 gallons*) of tap water (removes 4 ppm). Do not overdose!
So @ 2 ppm chloramine (my tap water value year round) I can treat a total of 526,400 gallons ....... with a single 4KG container of Seachem Safe. *