Tank size and lighting

[apet66]

I've had my reef tank running for almost 5 months now. It was a Craigslist purchase and I've been under the impression it is 35gal. Could someone better at math confirm this please?
15" front to back,
15.5" top to bottom,
36" long,
I'm running a 36" T5ho 2 bulb fixture currently, Solarmax H. O. 39w x 2, 78 watt and its sitting right on top of the tank.
T5 10,000k white,
T5 Actinic 03,
3 moonlight led.
Currently have mainly soft corals, mushrooms, candy canes, leathers, zoah's, green clove, Kenya tree, pulsating xenia, Duncan, star polyps, Acan, brain, green ridge coral and a Dendrophyllia.
I eventually want to upgrade the lights. I've heard lots of good stuff about the TaoTronics TT-AL09. At 15.5" top to bottom and 36" long would I need 2 of these fixtures side by side or only 1 hung higher over the tank?
I appreciate your help.

 

[CorallineAlgae]

You could get one and see how much spread it gives you. That fixture has 90° optics which you wouldn't need for a 15" deep tank. Removing them would increase the area of light cast over the tank.

 

[apet66]

You could get one and see how much spread it gives you. That fixture has 90° optics which you wouldn't need for a 15" deep tank. Removing them would increase the area of light cast over the tank.

That's what I'm struggling with, $190.00 for 1 or $380.00 if one doesn't do the job from side to side.
I'm not understanding the last part about removing the 90 degree optics. Is that the reflectors?

 

[CorallineAlgae]

Optics are tiny cone shaped reflectors that can be put on each LED. They work like flashlight where when you turn it the light beam gets more and more focused into a smaller and smaller spot. Using optics let's LEDs reach down deeper and more powerfully into deep tanks but limits the area that each LED emitter can light.

LEDs without optics are considered 180° and offer the widest light spread. If you use 90° optics the light will be stronger and reach deeper, but only over a smaller area. Having optics is like the magic bullet for lighting up a very tall tank. Removing the optics is useful, and often required, for lighting up a larger area of your tank with each fixture.

That fixture should be fine as long as you can raise it high enough to spread the light over the tank. You can just use the dimmer to make it strong enough for your corals. I doubt that you'll need to set it past 60% power even if it is raised 16" or more above your tank but if you need to that 120w fixture has all the power you need and more. The advantage to using two fixtures would be in letting you place them closer to the water at a much lower dimmer setting to light the whole tank.

Maybe you could PM Mr X about it. He's the resident sage for these fixtures.

 

[apet66]

Optics are tiny cone shaped reflectors that can be put on each LED. They work like flashlight where when you turn it the light beam gets more and more focused into a smaller and smaller spot. Using optics let's LEDs reach down deeper and more powerfully into deep tanks but limits the area that each LED emitter can light.

LEDs without optics are considered 180° and offer the widest light spread. If you use 90° optics the light will be stronger and reach deeper, but only over a smaller area. Having optics is like the magic bullet for lighting up a very tall tank. Removing the optics is useful, and often required, for lighting up a larger area of your tank with each fixture.

That fixture should be fine as long as you can raise it high enough to spread the light over the tank. You can just use the dimmer to make it strong enough for your corals. I doubt that you'll need to set it past 60% power even if it is raised 16" or more above your tank but if you need to that 120w fixture has all the power you need and more. The advantage to using two fixtures would be in letting you place them closer to the water at a much lower dimmer setting to light the whole tank.

Maybe you could PM Mr X about it. He's the resident sage for these fixtures.

Thank you very much!!! You explained it perfectly and I completely understand. At 15.5" deep I definitely won't need the optics. I just switched bulbs in my fixture and have pics on 35gal reef thread. Check it out and give me your opinion please. Thank you again for your informative explanation!

 

[CorallineAlgae]

You're welcome! I hope that helped but I'd love to hear from someone who has one of these over a 36" tank. Someone with a setup closer to yours would be ideal, especially if they had pics. I'll go check out your thread right now. ^_^

 

[apet66]

Anyone better with math than I am? Would still like to know if my tank is 35gal.