metal halide help

[craig_will2513]

hi all this is a lighting question i have a juwel 125 marine reef tank but at the min my 2x 28w isnt good enough and i cant seem to find a better light unit that will fit so my question is this. iam looking into metal halides and would like to know how many watts id need id love to keep all sorts inc nems at some point so id need light sufficient for them.. so if i get mh lights will the lamps have to run all the way along the tank so my tank is 80cm long would the light have to be80cm also i was worried that if its not i will have dark spots at either end now is this really a problem or would it be ok.. thanks guys

 

[craig_will2513]

by the way its a marine set up incase i didnt say

 

[Gti_Leo]

do you mean a 125 as in a 72"x18"x22"? if so then 3x250 watts, my personally opinion that is a waste and you're better off going with 6x80 watt t5hos or going with 12 39watt.you'll be using under 500 watts and put out the same PAR values as the MH if you use quality lamps like ATI,KZ or guiesmann and your color will be much nicer and make your corals look liek they are from the movie avatar, they will glow and stand out

 

[craig_will2513]

hi all.. so iv just been looking on ebay for a metal halide set up.. but iam a little confussed.. does the light system come in parts as iv just seen ballasts what is that could someone talk me through the set up please

 

[mr_X]

he means 80cm., which is roughly 31.5 inches. a metal halide covers a 24" x 24" area, so a single lamp is definitely going to leave you with dark corners. how deep is the tank from top to bottom? you could buy a 250 watt or 400 watt pendant (depending on the depth of the tank) and raise it up high enough to cover the entire thing, but you are going to have a lot of light spilling out around the tank.
as leo stated, you could go with a t5 HO fixture, but you would either be using a 30" fixture which only has 24" lamps in it, or a 36" fixture, which will hang over the sides of the tank a bit. i would probably use a 36" fixture. the 36" fixture's lamps are only about 34" anyway, so you aren't going to have a lot of light spilling over.

 

[craig_will2513]

hi my tank is 18 deep.

 

[mr_X]

yep. i also answered in your other thread. a 4 or better yet, 6 lamp 36" t5HO fixture would be what i would use.

 

[craig_will2513]

hi mr x and Carey. Sorry to be a pain and keep asking. But i have found a 150w metal Halide and 2 24w t5 be ok for nem

 

[mr_X]

possibly, but that's not a lot of light and you'll definitely see dark corners. it's unlikely you'll be happy with it IMO.