I only had enough water for 15 gallons that was left out for days to evaporate out bad stuff I do have Some Aquasafe that supposed to make tap water safe for fish should I use or let tank sit 2/3rds full for 24 hours to let water do its own evaparation process

Aquasafe is just fine to use... I use that too and itis great!

Go ahead and use it!

x2, on the other hand if you want the chlorine to evaporate you will need some current to keep the water moving, imo.

The point of the aquasafe or any dechlorinator is that you dont have to let the water sit. Just add the aquasafe and then put the fresh tap water into your tank

If the purpose of these products is to remove chlorine and chlorimines, ect.........Is there any benefit to using it on well water? Is it better to use the raw well water (iron and hydrogen sulphide in raw water) or after it is aerated and softened??? I've been adding water straight from the tap to replace weekly evaporation. But, I use raw well water that has sat 48 hours for water changes. I hope I'm doing the right thing. My oscars seem fine after these water additions. They play dead whenever they are frightened or something is not right. -charley

most quality declorinators not only remove clorine and clorimines but also aid in detoxifying ammonia nitrites and remove some heavy metals.
so i guess even if i were using well water i would still use a declorinator just to be safe.

but thats just me