Lighting a 36x36x27 Cube Tank

[ECreefer]

Going to be setting up a 36x36 cube and was trying to get some ideas on how to light it. It is going to be mostly SPS with some LPS and Softies (5-10%). I was thinking of doing a combo with a little of everything. This will be my first tank for using a Metal Halide and I could use a little advice with them. I have been using T5 for as long as I can remember so I figured I would mix it up on this tank.

I will be using a Radium on magnetic ballast and thinking of the Hamilton Cozumel Sun Fixture.
Atleast 4 T5 (Blue Plus with possibly Coral Plus if I think things get too blue) ATI Ballast or possibly Icecap
Cree LEDs 50-75 Royal Blue, Blue, some UV.
Curious as to what people think if I could use a single 250w? I could probably consider a 400w too. I really just don't want to get into 2 bulbs since I would have to buy double the equipment as well.

Do you think that fixture listed, 20x20 at 10-15 inches above the water, would provide a good amount of spread and PAR?

 

[sirreal63]

Yes, and a single 250 will be fine. Your plan is a solid one. For the T5 use the ATI ballast, it is correct for T5's and the IceCap is not.

 

[bristle]

27" tank...I think 250W with the supplemental lights will be fine but you may have colour issues on the periphery for your SPS at low depths. I'd go with a 400W light on a 36" cube so you can put anything anywhere.

 

[kc350twin]

I have a 36x36x20 and had one 250w Radium w/ 4 24" t5's and 2/ 24"reefbrites actinics. I had a small reflector (Lumenmax 2) over it at about 14" over the water. I could grow sps with no problem. I recently added a second reflector due to some shadowing issues. I had one laying around so that is why I went that route. If I were to do it again I would prob go with a large reflector like the Cozumel Sun and a 400w plus the T5's and ReefBrites.

 

[sirreal63]

The reflector is key to getting the light spread. The Cozumel Sun will effectively light that space, add in the 4-T5's and it is a near perfect setup. The 27" height is no problem for the bulb/ballast/reflector combination. You certainly could go to 400 watt bulbs, but the increase in heat and electrical usage for the gain in PAR isn't justified in this case, you will also probably be overdriving the bulb, which decreases bulb life.

 

[ECreefer]

All, you have made some really great points and I appreciate the info. It seems that my assumptions might be correct for using a 250w and that is great news!

Wondering now if the Cozumel Sun would provide the PAR that I'm looking for. Would the lumenbright large be a better idea, seems to still give decent spread but definitely gets more PAR into the tank with a 250w

 

[sirreal63]

Th LB is a spotlight, so if you are looking for a narrow beam of high par, then yes it is what you want. In order to get the same spread as the Hamilton, you will have to raise the LB very high, this will increase light spill and can reduce the total amount of light in the tank. The Hamilton is more of a flood light, meaning it is designed to spread the light out. For some people, raising the LB works but it has trade offs that you do not have with the Cozumel Sun. Either will work, but one was made cover a late area and the other wasn't.

 

[ECreefer]

Sirreal63, what are the trade offs that you would be referring to?

Also what kind of height would it have to be at to cover a 30x30 area do you think?

I guess it would be smarter to get the Hamilton and have it around 8-10 inches because I would get more punch with the T5 at that depth. Thoughts?

 

[ECreefer]

I have a 36x36x20 and had one 250w Radium w/ 4 24" t5's and 2/ 24"reefbrites actinics. I had a small reflector (Lumenmax 2) over it at about 14" over the water. I could grow sps with no problem. I recently added a second reflector due to some shadowing issues. I had one laying around so that is why I went that route. If I were to do it again I would prob go with a large reflector like the Cozumel Sun and a 400w plus the T5's and ReefBrites.

Were you running the T5 at that 14" of height? I'm not too concerned about growing the SPS, just concerned about getting the PAR for coloring them up. I'd like to get about 350-450 PAR about 12 inches down in the tank. And maybe 200ish at around 20. The Cozumel Sun with 400w should do that I'm guessing, but could the 250w do almost as well?

 

[sirreal63]

In order to get the same spread as the Hamilton, you will have to raise the LB very high, this will increase light spill and can reduce the total amount of light in the tank.

Sirreal63, what are the trade offs that you would be referring to?

Also what kind of height would it have to be at to cover a 30x30 area do you think?

I guess it would be smarter to get the Hamilton and have it around 8-10 inches because I would get more punch with the T5 at that depth. Thoughts?

Best guess is the bulb will be about 12" or so from the water, you will have to play with the height to find the best spot, it may need to be higher but I doubt it would need to be lower. Ideally with SPS you want as much even par on all of the growing area as you can get, if you plan on having a tank full of SPS. Hot spots of high par right next to low areas of par can be problematic.

Something you should consider, high par levels will mean an increased need for appropriate nutrition levels. Nutrition is every bit as important as light, in many cases it is more important. The higher the amount of light, the higher the nutritional needs. High levels of light and poor nutrition lead to pale corals.

Watch the BRS video of MH, it should answer your questions on spread.

 

[Icefire]

Some use 20k radium 400w as only source for a 36x36 cube

Myself I just ordered a 36x36x24 cube and will be using 3x Radion G2 and 2 Hydra52 with 6x Mp40