thanks this is all good info. im gunna go ahead and get the 250. probably a mh during the veg then switch it for a hps to flower. i wont be able to get it til next week so i'll try to put some pics up then and you can check em out give any suggestions
Don't get a MH. The whole MH for veg and HPS for flower thing is way overrated and a myth in my opinion.
HPS has a better watt to lumen ratio than MH so you're going to get more lumens from the HPS than the MH.
Go HPS all the way if you're going 250 and use the money you are planning to spend on a MH and buy a nice Can Fan.
Or even better, with the extra cash you would spend on MH bulb, get a Lumatek digital ballast instead of a magnetic ballast. They are advertised as 30% more lumens than a magnetic ballast but I've been told they only give about about 5% to 10% more. Still, more light is always better.
People are probably going to argue this one because because there are so many people out there that believe the spectrum thing has such a big impact. I know some of the best growers in CA and they all use HPS all the way.
I used to be a MH vegger and a HPS flowerer until I took the advice to go 100% HPS. I have noticed no reduction in cropsize. What I have noticed though is that I am getting higher yields now that I switched to digital ballasts.