Best Deal on Indoor Grow Tent

Have a 2x4 grow table. Debating if 2x4x6 or 4x4x6 ould be better with 600w cool tube setup. That being said, where can you find the best band for your buck? Want a quality grow space, but don't want to spend the big $$$ on it.

I have a Grow Lab and I'm very pleased with it. Look on line or Craig's list.

peaktop.us on ebay, good quality tents, wont hold co2 but are light proof and sturdy.
for a 600w light i would go with a 3x3 or 4x4.