Lighting for 20g long Frag Tank - T5 2 bulb or 4 bulb?

[jdm85]

Looking to switch back to T5 lighting for my Frag tank
Would a 2 bulb be sufficient or should I go with a 4 bulb

Looking for ATi Aqua Blue Special and Coral Plus mix

Frags are mixed LPS and SPS

I prefered the growth when i was using T5's

 

[jda]

2 is probably OK if the corals are up high on a rack and shallow. If you want to have them on the bottom, then get a 4.

 

[jdm85]

Corals are sitting 8 inches under the water line

 

[jda]

I think that you can probably expect about 80-100 PAR from a good reef bulb on a good ballast and good reflector at that level... something like ATI. Figure on less PAR with an inferior fixture, but unknown how much.

I have a 4 bulb hydroponics fixture (inferior to ATI) and I get about 280-300 PAR with 4 bulbs dead-butt in the middle about 8" deep with GE 6500k bulbs which have more PAR than a B+ or C+. I would expect about 220-250 with B+ or C+ bulbs. This fixture is good for a fuge where I mostly grow macro and rear smaller clams, but I would get a better one if I was growing coral in there.

 

[jdm85]

I would like 350ish par right in the middle for my sps. I would move my acans, Zoas and torches off to the sides

I was going to use one of the hydroponic fixtures

 

[jda]

Get a 4, but get an ATI. Those hydroponics ones are not powerful enough for 350.