Lighting for new 180cm tank 39w (or) 80w (or) 70w ???

Gilles

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So i am building a new tank; 180cm wide, 70cm deep and 60cm high.

So far so good, but now i am in doubt about my lights. This is not so much a question on how much bulbs, since i am allready set i am going for 5 dimmable and switchable rows :p

The remaining question is this:
a) Go for 2x T5 HO 39w bulbs per row side by side (so 10 lamps in total)
Pro: is that i can light one side of the tank with more pars, or other colors
Con: need twice as much ballasts

b) Go for 1x T5 HO 80w bulb per row (so 5 lamps in total)
Pro: 80w will most likely penetrate deeper into the water then 39w?
Con: is limited to 1.5 meter in length, however i wonder if it will affect me since i can spread my lights.

c) Go for 1x T8 HO 70w bulb per row (5 lamps in total)
Pro: with 176cm it best matches my tank width
Pro: most efficient (10w less then the 80w version, while keeping thesame lumens)
Con: Not available in 6500K (from Philips at least)

As far as "C" is concerned; with T8 lights nowadays the decrease in lamp output and lamp life versus T5 is negligible (dutch site)..

Your thoughts are welcome :gw
 

dutchy

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I'd go for the 39 Watts too, more uniform spread, but I would use just 4 rows with 4 ballasts, total of 8 lamps. Much cheaper and more than enough light.

I am also using that on my tank, which almost has the same dimensions, 180 x 60 x 65, and I am not even using reflectors.

So I think you can save yourself a lot of money by buying four double fixtures, each with one ballast and still have all the light you want, providing you will use good reflectors.

regards,
dutchy
 

Gilles

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Yeah you are right. The difference between 5 ballast which powers 2 lights versus 10 ballasts which power 10 lights is huge.