after some posting here it seems i should invest into cfl lamps since i cannot use more than 100w because of living in student accomodation and this would be more worth it than 100w sodium.

but i dont really understand howmuch electricity these use compared to sodium. if i am limited to, say, 100w on a sodium lamp to keep it all very discrete, what would be the equivalent for a cfl lamp?

is this for example a good alternative?
eBay.co.uk: 125w Eco-Light GROW complete <Hydroponics> Ecolite CFL (item 290076301016 end time 04-Feb-07 18:04:06 GMT)

thanks!

Thats cfl is 125 watts. Clearly more than 100 watts. They sell packs of 26w cfls at walmar go get a couple.

but will the one u speak of do as much as 100w sodium then? if so why doesnt everyone just convert to these?

26 w will get you through the veg period, and flowering too I suppose, but you will end up with long stretched out plants, and a sad yield, and sad potency too!

Why do you say you can only use 100w. Do the room rules give you a limit?
Or does a breaker trip? 125 cfl may work, just tell me what your electrical situation is.

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Dude you should be fine running a 150w light. Regular incandescent bulbs in ceilings and such are 60w. So it would be less than 3 of those. Replace your incandescents with 13w cfls and get an HPS. Or get some 42w CFLs.