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Best Low/Medium Light for 90gal

1177 Views 10 Replies 4 Participants Last post by  lauraleellbp
Hello all, I'm hoping to find some advice on what light to purchase for a new 90gal tank. I'm planning on doing a low-tech discus tank. What would you guys suggest? I'm thinking of a 2x54W T5-HO... please and thank you for any help!
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A T5HO 2 bulb light will be too much light unless you hang the light about 6-8 inches above the top of the tank. And, an 18 inch front to back tank will get much more uniform light from bulbs much more widely spaced than any standard 2 bulb fixture. One alternative is two of these, one near the front and one near the back of the tank. Another alternative is to order a custom fixture from Catalina Aquarium, a two bulb fixture made with a 12 inch wide housing, to keep the bulbs about 10 inches apart - I would be very tempted to try the latter ldea.
I run 2x 54 watts of T5HO over my own 90gal (is a 4x54 Solar fixture from Catalina) and it's a challenge to avoid algae; I can only run a 6-7 hour photoperiod.

I agree with Hoppy that if you decide to go that direction, the best way to make it work is to space the bulbs out as far as possible, and hang the fixture up off the tank rather than using the legs like the way mine is set up.

I love the fixture, but if I had it to do over, I'd go with 2 Coralife T5NOs so that I could run a much longer photoperiod:
Any opinion on the marineland double bright LEDs?
Yea... and it looks like they don't have a 48in fixture...
Yea... and it looks like they don't have a 48in fixture...
Yeah they do. There's a drop down menu you have to change from 24" to 48".

Big Als just recently redesigned their website and IMO it's horrible now.
... if I had it to do over, I'd go with 2 Coralife T5NOs so that I could run a much longer photoperiod:
Would this be considered medium light, low?
Well they have a 36" fixture, that will extend (with feet or something) to 48... the fixture isn't actually that big though.

-And I completely agree with you on the Big Al's site!

What about opinions on the Fishneedit. 4ft fixture... it's HO so I'd either run the two outers and hang it... or switch them out for NO bulbs... which is still pretty cheap. Thoughts?
You can't switch the HO bulbs for NO bulbs and get much less light. You would just be overdriving the NO bulbs, shortening their life, but still getting about the same light as from HO bulbs.

The 2 Coralife T5NO 2 bulb fixtures, separated by several inches, should give you low medium light on a 90 gallon tank.
One of the things that really appeals to me about running 2 of the T5NO fixtures is that then I could play quite a bit with the photoperiod (running just one fixture, or both, for differing amounts of time) to dial in what works best for my tank. I'd probably run just one for most of the day, with a short "noon burst" with the 2nd fixture, to keep the tank low light.

The Coralife fixtures are very slim (4"), so 2 would easily fit on a 90gal tank.
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