6 or 8 ATI Sunpower on wide tank?

[poidog81]

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.

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. I'm keeping SPS on the top rack and then LPS on the bottom rack and around the edges of the top.

Which bulb fixture # 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

Thanks for your help!

[karsseboom]

I would get the 8 bulb if the tank is 36 wide. That is pretty darn wide and should be plenty of par for the Sps. Infact the ati fixture is one of the most proven ways to grow Sps.

[poidog81]

Any input from the morning crowd?

[ABlueReef]

I was running a 8 power module fixture on a 30 inch wide tank before and liked it very much. My bulb combination was: 2- Ati Aqua Specials, 4-Ati blue plus, 2- Atinic. The only down side was when it came time for bulb replacement.

[poidog81]

ABlue - how was the PAR, particularly around the edges of the tank, with the 8?

[ABlueReef]

I didn't have an apogee par meter, but the tank I ran it on was a oceanic tech 120 (24" deep) and most of my sps were sitting about half way up from the sand bed. The t-5, gave it more than enough par and the growth was outstanding. I have a buddy that runs a 4ft 10 bulb powermodule on his elos 120xl and the colors of the coral were phenomenal.

[Donkeykong]

ya with a tank that wide I would go atleast 8 bulb, you still will have low light areas at the front and back edges which will give you room to play with for the lower light lps.

[TylerHaworth]

At least 8, I found five bulbs to barely be enough for an 18' wide tank.

[bryman]

Eric,
I'd go with the 8 bulb, but do:
- 4 blue +
- 2 coral +
- 2 purple +

I run 4 blue+, 1 purple +, and 1 coral + in my 6 bulb Sunpower right now and have to hide my few chalices under a ledge on the sand, about 33" from the lights. I'd say the look in my tank is about 15k. No worries about enough par when using ATI fixtures and bulbs.

[poidog81]

Thanks. Not looking if its enough PAR, I know the ATI will produce that. What I'm concerned about will the 8 bulb offer too much spread for too much PAR for the lower light LPS, ie chalices/acans.

[bryman]

Eric,

Just make sure you use the adjustable hanging mounts and raise them way up if you have an issue. Or you can always take out a few bulbs if 8 is too much. At least with the 8 bulb you have more options. Or you can be super fancy and get the dimmable unit

[poidog81]

Very true. I know! The dimmable is so cool but more $$$ and I read that dimming the bulbs cuts their life in half....?

[fishnerd1]

I've got the 6 bulb on my 30" tank which is enough light but with 36" I'd step up to the 8 bulb. Like everyone is saying you can always drop a couple bulbs or raise them up if needed. Much cheaper than buying another one for more light if you end up needing it. The ATI's do kick our some light.

[karsseboom]

For reference I have an 8 bulb powermodule on a tank that is 20 inches wide. I didn't go with the 6 bulb since my tank is full sps.

[TommyA]

Go eight or more,I run a six bulb sun power on my 75 that are 48 inches.

[Michigan Mike]

Figure out the size of the area that will be SPS and have the fixture be roughly the same size of the area that will contain SPS. The spillover will be plenty for lps. Honestly the ATI are so powerful they take conventional thinking of how you set up t5 and blow it away. You'll have the fixture a foot above the tank and still have extremely high par under it.

[poidog81]

Thanks everyone for your opinions. They've been very helpful! I've decided to go with the 8 bulb fixture, even though the 6 bulb would be more than ample I think. The difference between the 6 and 8 bulb is $70. I have a feeling the 8 will be too strong in the beginning, but I can take some lamps out if it's too strong. I think for $70 I'll take the added flexibility were if I want/need more light on top I can run all 8 lamps, and as the top rack starts to fill and shades the lower rack more I'll need to push some additional light in there.