6 or 8 ATI Sunpower on wide tank?

poidog

poidog

Active member
Hey Gang,

I've been doing a lot of researching on getting either an 8 or 6 bulb ATI fixture and I need some help, I'm still stumped. I have narrowed it down to a 36" length though. Since my world has always been MH, T5s are new to me.

The tank is 48" long 36" wide and i'm using for a frag tank, there will be two racks, one about 6" under surface, the other about 16" below and under the first rack (so it will receive shade from the rack and those above it). I'm keeping SPS on the top rack and then LPS on the bottom rack and around the edges of the top.

Which # of bulb fixture would be best to provide the right light to appease the SPS (~400+ PAR) on the top and enough spread to cover the tank without frying the acans/chalices on the lower rack/edges (Those I keep at sub 100 PAR levels)?

For bulbs I was thinking of running:
6 - 3 coral+, 3 blue+
8 - 3 coral+, 3 blue+, 2 actinic (but also don't want to then look too purple)

Thanks for your help!
 
I'm no expert either, but I've had my sunpower for a few months now and I have to say its way more powerful than it looks. I had the 6 bulb 24w fixture 6" over the tank and I bleached some coral when I first started running it. Now at around 10-12" things have colored up better.

I think 6 bulbs is perfect and could even be borderline too much depending on how high the coral are.
 
IMO the 8 bulb, should be perfect and give you a chance to play with combos. Also since this tank is 36" wide.. Hanging 10" or 12" off water should give you a nice spread all over the tank ;)

My 2000 post.. :D
 
The SunPower is very efficient. That close to the surface your sps will have 400+ par under either fixture, but you probably should do the 8 bulb regardless for the front to back spread, the extra 2 bulbs will help a lot. Don't expect too much at the ends of the tank that high up thou, it may be worth considering the full 48" wide fixture to get good PAR output from end to end.
 
Thanks all so far.... keep the suggestions coming!

If I was going to do max output full PAR potential then I would have def gotten the 48" and then 8/10 bulb combo, but since this will be mixed sps/lps I need areas were it will be 100 par or less in the tank for them (either bottom rack or on the sides).

the 36" long gives me more shaded spots at the ends of the tanks, but the main concern is the width between the 6 and 8 bulbs as I don't want the 8 to be too much PAR spread that makes the ends of the tank unusable for LPS (or even too much with depth penetration where the lower rack is too high of par). Also there is a pretty good cost difference between the 6 and 8 bulb.

hmmmmmm. also on a side note, I've been thinking of changing fom my MH on my display tank because now I've seen first hand the colors T5 does... wow.
 
It will be a lot less light at the ends than you think. I've got frag racks at the end of a 72" tank, with an 8x80w 60" fixture over it, and even palys on those racks will reach for light, at the same time, move those frags to the sandbed 2 feet below water under the light, and they will flatten back out on the plug and regain color. I could only guess it would be worse for Lps corals that need more light than polyps to get stuck in those dead zones of the tank.

The option would be to raise the fixture to get more spread at the ends, but then you sacrifice the PAR levels and intensity under the light as you raise it farther from the water surface.

If you want to get really fancy with the lighting, you could look into the Dimmable SunPower, and special order a 8 bulb so the outer 4 bulbs are on one channel and the inner 4 on the other. Have higher light output from the inner bulbs, and adjust the output of the outer bulbs as necessary to get just the right amount of light to the corals lower in the tank.
 
George, the dimmable option would be best I would say, never thought of that, but don't want to drop that kind of money.

The light will be at least 12" off the water to give me work space in the tank.

Right now my "temporary" fixture, until I decied on what ATI go go with is an 8 bulb aqua medic and 12" off the water - on the top rack I'm getting 250 under the fixture, 50-100 PAR around the top edges. 1/2 those values on the bottom rack. Raise the light up to 16-18" above the water and I get 200 in the center and 50 around the edges.
 
That high up if you have an acrylic shield on the fixture, you can take that off, you will see an increase in PAR at the same 12" height. Regardless, the ATI will kill the AquaticLife for output even with its splash shield in place. IIRC, on my 6 bulb SunPower set at 100% on both channels, at the surface with fixture about 6-8" above water I saw around 450+ par an inch or so below water, and still around 200+ 2 feet below at the sand. This was all ATI and KZ bulbs. 24" wide fixture over a 24" cube. Corners of the tank still had 150+ at the sand.
 
Ya, def no shield, and those aquamedic numbers are with no shield. I figured the ATI will double the numbers I'm getting from the aquamedic.

Thanks for your help. so if you were me 6 or 8?
 
Okay, thanks george. You don't think that spread will then dump too much PAR (more than 100) to the LPS.

Also food for thought I can get a gently used under 1 yr 6 bulb for $250 shipped, or a new 8 bulb for $500 shipped.
 
As long as you keep your higher PAR bulbs towards the middle of the fixture with your supplements near the outer ends, all should be well. Your sps will still get the full output and spectrum from all the bulbs, and the highest output bulbs will be shaded on the way deeper into the tank. Could also help to have a larger footprint on the lower rack as well, like the way Midwest Coral Farms had their frag tank setup so you can put stuff out around the lower rack with less shading but not as much light as the upper rack.
 
poidog said:
Okay, thanks george. You don't think that spread will then dump too much PAR (more than 100) to the LPS.

Also food for thought I can get a gently used under 1 yr 6 bulb for $250 shipped, or a new 8 bulb for $500 shipped.
Click to expand...

I say do the 6 bulb and make it work. That's quite a big difference for 2 bulbs.
 
I'd get the six bulb that you can get for a great price and align it with the back third of the tank. Then buy another, much cheaper, 2 bulb T5 fixture and put it over the front of the tank. LPS and softies should be happy in the front bottom of the tank, while the SPS will be happy as and with clams everywhere else. :D
 
Or do I do both and use the 6 bulb on my display and the 8 on the stock tank?

I was really impressed by colors that T5 brings out.
 
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