I like the look so far, those must be some happy tetras. Much better than my first "attempts"
All those tanins might be coming from your dirt. I have a 20 gallon im working on now that turned to tea after water changes. Try adding a little purigen in a nylon bag to your filter. Clears it up beautifully.
Yep, our neons are happy little dudes. They school merrily all day long.
Yes, we had tanin problems when we added our dirt. We also had problems with the dirt and bark floating to the top. Next time, we plan on soaking our dirt longer, so hopefully that will help. To clear up the water we did partial water changes everyday for a few weeks. It was a hassle, but we've decided to steer clear of synthetic additives as much as possible ^_^.
Good luck with your 20 gallon! I hope to see pictures. We're making plans for a 20 gallon too!