View Full Version : Urgent What power T5 for my 170gal (640L)

07/01/2011, 02:12 AM

First I am sorry for my bad English, I translate with google! :rolleyes:

I have a 170gal tank (640L) - 160x70cm height 60cm.

With full SPS / LPS, what T5 power you advise me?

8x80W or 8x54W suffice? I'm not sure of my choice!

Thank you in advance for your help. :thumbsup:

07/01/2011, 02:23 AM
The 54w bulbs are 46" and the 80w bulbs are 58" IIRC. With the 8x54w light you will have less light on the very outer edges of the tank. The 8x80w should cover the entire length of the tank. If you do not plan on putting high light corals on the side of the tank then you would probably be good using the 8x54w.

07/01/2011, 05:31 AM
Ok, but 8x54W seems low for 170 gal?

07/01/2011, 09:16 PM
With T5HO bulbs the light output is spread thruought the whole bulb as opposed to MH or LED where the light output is a single point source of light. This basically means that in a linear type of bulb like the T5's, the wattage is spread out across the usable part of the bulb. In the case of the 54w bulb, the bulbs total lenght is 46" and the usable part of the bulb is only 2 +/- inches less. If we just use the total length of 46" for the 54w bulb you get an average of 1.174w per inch. For the 80w 58" bulb you get an average of 1.379w per inch. To me that is not a whole lot of difference and I do not think that they would have very much par difference under the center of each bulb. In the case of these bulbs the extra wattage is used to light the extra length of the longer bulb.