lol now now kids, let's play nice
he never mentioned what shade of green, transparency, smell
it could be tannins, have you ever seen a light green lake
i have, take a limnology course and you'll see amazing lakes from around the world as well as the reasons behind them.
i have raised gorgeous goldfish in opaque wintergreen algae water. they LOVE the stuff!
if it stinks, you may have an issue
don't use gravel, use large grain sand
lakes don't have gravel as a substrate 
take your water to a fish store and have them check it. even petco does that. good luck. be sure to list parameters as they probably won't be able to tell you what's wrong
he never mentioned what shade of green, transparency, smell
it could be tannins, have you ever seen a light green lake
i have raised gorgeous goldfish in opaque wintergreen algae water. they LOVE the stuff!
if it stinks, you may have an issue
take your water to a fish store and have them check it. even petco does that. good luck. be sure to list parameters as they probably won't be able to tell you what's wrong