My first REAL grow..Need Help and suggestions

I've been reading these forums for a long time ,but just got around to registering. I've done a couple previous grows before ,but none were successful so, im doing this one right.

So here's what i plan on doing.

Around 4 or so lowlife autoflowering plants
(2)ak47 (2) blueberry

A 5'H x 3'L x 2'D grow box.

Some CFLs to start off with

400 watt HPS grow light W/6inch cool tube for flowering

Cover the inside of my box in mylar.

I'm going to have a carbon filter located inside my box with a 170cfm 4" centrifugal fan pulling air through it then through my cool tube, and then dumped outside the box.

(1) maybe (2) 120mm fans for my intake.

I need some suggestions on what type of nutes i should use. I plan on building my box frame with 2x4s and covering it with some thin MDF or even hard board.



I'm just looking for any suggestions or input on my grow box and plans.

Thanksss

2x4s and MDF/ would be very much over-kill, not to mention expensive. Your box will end up weighing a ton as well (trust me I've built a grow box with 2x4s and MDF, getting it up the stairs was a BITCH and it was smaller than your plans).
I would use 2x2s or PVC to build a frame and wrap it in panda plastic or a cheep imitation (they work the same).
There really isn't a need to make the grow space so solid, I would go for more of a grow tent.

Everything else you have planned sounds good though, good luck with your grow!

Anyone else have any more input?