Metal Halides, Heat and Light Levels

[dick_turpine]

Hey folks,

what's your thoughts on metal halides? I have used 2 x 600w sunnmaster cool deluxe for vegging over the last few years but they get so bloody hot and when the ambient temp rises in the summer it becomes a real headache.

I have some budget 250w MH's but the light seems a little dim although room temp lovely down around 25c all day long. I want to kick-start my first soil grow, so i put in the 600 w Sunnmasters earlier today, temp in the room went straight up to around 34c, unacceptably high, RH dropped right down too, obvs.

Now here's the thing. With the 250's, lux hitting my clones was about 5,000 - 10,000 depending on where in the room they are situated.

With the 600's, i had to move the lights up a bit to prevent overheat, and i was getting 12,000 to 17,000 on the clones although they were all getting a good dose as the light reached into the corners better.

The room's 32.5 sqft so with the 250's, that's 1,400 initial lumens per sq ft (seems a bit low) and with the 600's it's about 3.500 per sq ft. Therefore, heading into veg, the latter seems more reasonable and i trust the sunnmaster to have a better spectrum than the budget bulbs.

As a 3rd option, i could use full-spectrum hps although i've just tried 2 x 6oow grolux full spectrums and temp and lux seems approx the same as the 2 x 6oow Sunnmaster MH's. So how come these HPS give me about 5,0000 initial lumens per sq ft but the same amount of light is actually hitting the plants?

So what do you reckon? Keep temp low and compromise on lumens or let the room heat up to get the extra light?

Maybe i should get a bigger fan?

Cheers,
D