That's 66 US gallons, lucky man, lucky man! Wouldn't I love to have 66 gallons worth of plants and tetras!... shoals and shoals, sigh.
Since you started with the complete water change and only lost one, you've already proven they can take it or you've already started what's going to happen.. lets put it that way. So I'd say.. go for it! Keep doing some really large, really frequent water changes, with good technique and it'll help with the green water situation even more. Meanwhile, try to keep the blackout thing going for 3 full days..I think I remember the plant guys saying that's the trick.
Be getting a good liquid-reagent based test kit so that you can have good feedback on your fish-in cycle and not have to change more water than you really need to!
~~waterdrop~~