Your asking a different q now......I'm pretty sure I read something about not interchanging different sized ballasts/bulbs but I'm not 100% positive.

Stealth if you're going to start a fair amount of plants you most likely WOULD want the 400 vs 250.....when you think about it a 2' x 2' area really isn't very big.....while it works for us remember we've only got 4 plants going under it at any one time maximum.
Weedhound Reviewed by Weedhound on . TEST LAUNCH-Operation Redwood Tree Welcome to my new log. In this log I'm going to follow 2 grows, one very simple and a new grow doing something I haven't tried before. This time I'm going to try and go for the biggest plants I can get....and a record yield as well. :stoned: I'll be using buckets like the one below to flower the plants with. I have two of them and each one will hold about 6-7 gallons of water (when half full which is how they will be used) in a DWC/drip ring setup that hopefully will have enough room Rating: 5