t5 lighting question

[easternreefer]

90 gallon build. standard size. I have 2 24 inch 4bulb t5 fixtures.. planned for softie/lps.. no intention of sps. enough? too much? not enough?

 

[clsanchez77]

Will 2-24" fixtures fit over a 90 side by side?

For LPS and softies (generally) you will be fine.

 

[40B Knasty]

I have a 4x39W JBJ Trinity 36" over a 40B.
Bulbs: ATI Blue Plus, Coral Plus, Blue Plus, and True Actinic.
Corals:16 Zoas, 2 frogspawns, 2 Aussie gold torches, pulsing Xenia, 4 month old maxima clam, and candy cane all doing great under T5s.
I don't understand why you will use a 2x24" for a 90 gallon tank.
You need to get enough PAR on the farthest points of your tank. So 4 bulbs minimum and probably 4x54W 46" with bulbs of your choice.
On the 90g top. Does it have 2 separate glass top openings and you want to put your 2 light fixtures with 4 bulbs on each side resting on a glass top?
That I could see working.

 

[easternreefer]

short answer. the 90g is braced in the middle.. so yes one on each side.

longer answer standard 90g 48 X 18 X 24. there are two fixtures that are 24 inches with 4 bulbs in each. one fixture will be placed on each side of the tank. for a total of 196 watts of t5 over the tank. I understand that PAR needs to reach the areas that I want corals in, hence the question as to whether it is enough? too much? or not enough?

 

[40B Knasty]

short answer. the 90g is braced in the middle.. so yes one on each side.

longer answer standard 90g 48 X 18 X 24. there are two fixtures that are 24 inches with 4 bulbs in each. one fixture will be placed on each side of the tank. for a total of 196 watts of t5 over the tank. I understand that PAR needs to reach the areas that I want corals in, hence the question as to whether it is enough? too much? or not enough?

The PAR would matter on the bulb. Here is some fun facts I dug up. See the difference between a True Actinic & a Blue Plus. This is at 0hrs & 100hrs of run time.
I am just thinking about long term cost of changing out 8x"24W" x $20.95= $167.60 every 10 months for less PAR vs a 4x"54W" x $21.99 =$87.96 every 10 months for more PAR. $79.64 saved a year.
Plus the lumens of a 54W bulb compared to a 24W is around 35% more. I am no light expert to tell you what the difference of how much the light will penetrate 24" of water depth better for PAR ratings. My guess is 54W being at an average of 35% more will be better to have. You can always cut back on run time during the day to give the corals what they need for lighting for photosynthesis. You don't want to cut back on intensity/depth penetration. Then you don't get that light reflection off your substrate to keep the underside of the coral's flesh/zooxanthellae fed and to stay healthy. Hope this helps.