6 Bulb on a 120???

[john.m.cole3]

I have a 6 bulb 48" ATI fixture on my 72 gal. It's way more than enough light for that tank. Do you think I could use the same fixture on a standard 120 (4x2x2)?

 

[iLLwiLL]

Of course you can. Might have to raise it up a little for the spread but it all comes down to how much light that 120 is going to need.

 

[john.m.cole3]

It's prob gonna be 2/3 LPS and 1/3 SPS

 

[pgammon]

That's the fixture I have on my 120 and it works fine. I have plating and encrusting monti's that are doing fine. I'm not really consistent enough to try acros. HTH

 

[mcarroll]

Might have to raise it up a little for the spread

Doubling the distance to the water will cut intensity by half, so there really isn't very much room at all to raise the fixture unless it's being run partly dimmed right now.

You don't want to cut the light to existing corals by half....or anything remotely close to half. I wouldn't purposefully change levels more than 2000 lux per week, or even two weeks.

Honestly, it's still a 48" tank and it was a little bit overkill for a 72-gallon, so I don't see needing to raise it anyway.

At most it might end up riding the front of the tank a little bit vs being dead center from front to back. Usually not a big deal since that keeps the back wall and drains from growing algae quite a fast.

...and even that might not be needed.

 

[saltyfilmfolks]

just get the spread imo.
keeping in mind my xenia some palys, some zoas, several acros, gorgs, a sinularia, a purple photosynthetic sponge, a stylo a ponape birds nest are all at the same level in my tank. the top. 12in from the lights at 40,000 lux.
read up on russ265 corals are paling thread.
I wouldn't dim a tube unless i was acclimating. burns it up faster. id rather pull a tube. or add one if I was acclimating the tank to it..

 

[iLLwiLL]

Doubling the distance to the water will cut intensity by half, so there really isn't very much room at all to raise the fixture unless it's being run partly dimmed right now.

Who said anything about doubling the distance from the water? I just said he might have to raise it up a bit ... maybe 2-3 inches to cover the corners in the new wider tank.

 

[mcarroll]

I guess I'm assuming the light is sitting on the tank, or otherwise very close since it was on a "skinny" 72 gallon tank.

Assuming that's the case, the light may only be 5" from the water. 2-3" would be double.

I could easily be wrong and the light is already a foot off the tank, but that would seem weird on this tank.

 

[mcarroll]

(Thought even if it's already a foot off the tank, a 3" difference would still be a 25% change in light intensity....probably still more than I'd do in one change.)

 

[mcarroll]

I just wouldn't move it in "inches" at all....move it in lux or PAR, if you have to move it.

 

[Bpb]

I think it would be fine honestly. A 120 is taller and that means it'll spread better down low than it currently does (the tank itself gives you more distance to the substrate. Just place your higher light corals directly under it. If eventually you find it's not enough you can pick up a giesemann razor, or Hamilton 2x54 watt t5ho retrofit kit and drop that right in with it to bring yourself to 8 bulbs

 

[john.m.cole3]

I think it would be fine honestly. A 120 is taller and that means it'll spread better down low than it currently does (the tank itself gives you more distance to the substrate. Just place your higher light corals directly under it. If eventually you find it's not enough you can pick up a giesemann razor, or Hamilton 2x54 watt t5ho retrofit kit and drop that right in with it to bring yourself to 8 bulbs

That's a good idea if needed. Right now my fixture is 20" above the water line while I burn in these new bulbs. I hope to have the 6 bulb 10 inches or less above water when I transfer over to the 120. I'm trying to get all my equipment sorted out before buying the glass box itself.

 

[DMCM]

i have the same fixture on my 120 about 10 to 12 inches above the tank and my corals doing fine.