First grow, 1xBlackjack 1xEldorado

Here are some pics of my first attempt, the plant on the left is blackjack the right one is El Dorado. Both were grown from feminized seeds.
I haven't been keeping track of the dates like I should, but I think these were germinated 3 weeks ago. I haven't been feeding them much. when I first put them into the bubbleponics as seedlings I failed to follow instructions and put a whole bag of micro nutes into the water and half a bag of grow nutes, I started seeing the underside of the first two real leaves turn purple as they shriveled up and freaked out. So I cleaned out my reservoir and didn't give them any nutes for about a week. They started growing and for about a week remained yellow so I added about a table spoon of micro and grow nutes and it seems to have turned them green again, that was about 5 days ago.
I'm figuring on feeding them tablespoon increments of nutes as they appear to need it, turning yellow. Maybe that's a bad Idea?
Please give me some feedback on my setup. How big can these guys get before I have to upgrade the lights? Also, have they entered into the vegetative phase yet?

Thanks guys. I love this forum.

id take that tinfoil off of the bubbleponics system it isnt doing anything but creatin hotspots, they have been in the vegetative state since they were sprouted from seed, what schedule you got em on? and you can veg a plant for a month or two under those lights (tho not ideal) I would switch to at least a 150W hps with those cfls as supplemental light when you switch it over to 12/12 for flowering.