250 watt or 400 watt metal halide?

[Rcollick]

My tank is 36x24x20 deep. I just picked up a cebu sun 24" figure for it. Im running 2 ati blue plus 1 purple plus and 1 actinic. Heat and electricity isn't an issue. It's only a single 250. Should I swap it for a 400 watt radium. It's open top.

 

[speedstar]

36 inches is quite a spread, I have gone 30 before with single fixture, but that is gonna be a stretch that imo won't be filled by increasing the wattage, unless you also lift the canopy higher. 250w is plenty to penitrate 20 inches deep

 

[KrisReef]

What are you going to house in the system? Speedstar got the coverage correct. If you center the MH, the edges of the tank will be great for lower light species and the middle you can have a nice clam or other PAR hungry dweller. GL! Post pics!

 

[Rcollick]

I really only need 24" of coverage for sps. The 6" on both sides are for the lower light lovers.

 

[speedstar]

I really only need 24" of coverage for sps. The 6" on both sides are for the lower light lovers.

Then I would stick with the 250 on a tank that deep.

 

[vanpire]

For “very” wide tanks, you should get larger reflectors instead of higher wattage. Lumenarcs, large lumenbrites, etc will serve you well with wide coverage. I think the reflectors are what makes metal halide cost effective for large area coverage.

 

[vanpire]

duplicate

 

[Mal11224]

I have a similar tank size and just swapped out my aquatic life fixture with a Cebu sun 36" fixture. With two 250 w fixtures. It has been great over my tank. I have it about 10" above the water. Corals responded nicely to the change.

 

[pdxmonkeyboy]

250 for sure. a radium 250 to be exact

 

[Rcollick]

250 for sure. a radium 250 to be exact

Yes I hear great things about the 250 radium but I think it would be under driven on the luxcore ballast even at the hqi setting. I really want to run that bulb though.

 

[maroun.c]

I'd go with 2 x250W to cover the 36 inch span unless you only have a single island in the middle and don't mind a bit of shadow on the sides.

 

[Rcollick]

I'd go with 2 x250W to cover the 36 inch span unless you only have a single island in the middle and don't mind a bit of shadow on the sides.

I already bought the fixture. It's the 24" hamilton cebu sun 250 watt metal halide with 4 t5s 2 blue plus 1 purple plus and 1 actinic. Also 2 24" reef brite xho. Just hoping it's enough light.

 

[jda]

For me, it would depend what you are running now. If it is 250w 20K Radium on m80 ballast (true HQI), then going to a 400w won't gain much since most 400w bulbs are not much more output than a 250w on m80. If you are running a regular magnetic or electronic 250w ballast, then a 400w could be a nice jump.

Check out the PPFD (PAR) difference in the m80 driven 250w Radium vs a normal 400w Radium... about 10%:

 

[Rcollick]

For me, it would depend what you are running now. If it is 250w 20K Radium on m80 ballast (true HQI), then going to a 400w won't gain much since most 400w bulbs are not much more output than a 250w on m80. If you are running a regular magnetic or electronic 250w ballast, then a 400w could be a nice jump.

Check out the PPFD (PAR) difference in the m80 driven 250w Radium vs a normal 400w Radium... about 10%:

The ballast is a luxcore select a watt and has the hqi setting.

 

[jda]

The select-a-watt stuff can get close to m80... factor about mid-way between a m58/electronic and a real m80 ballast.

This website that will graph this stuff was well before any selectable ballasts were around.

 

[Rcollick]

The select-a-watt stuff can get close to m80... factor about mid-way between a m58/electronic and a real m80 ballast.

This website that will graph this stuff was well before any selectable ballasts were around.

Do you think I would be better off with a radium bulb or something in the 10k range with more par. I do like the more blue look though. I'm not even sure what bulb it has right now. I bought it used and just set it up yesterday.

 

[jda]

Color temp is totally up to you. Any of those bulbs is going to grow coral pretty well. If you do go 10k, the Hamilton and XM 10k bulbs are really nice white with good blue pop (XM is out of business, so hard to find them lately). 14k is a good compromise.

 

[maroun.c]

The 4 T5s shoydl provide enough light to light up the sides of the tank.
Bulb choice is a very perosnal choice. The T5s will help with supplementation to get the final color u like .
I prefer abd still run 14 K bulbs which provide a nice mixe of white and blue with decent par and very good rendition in camera shots straight out of cam. I go with 250 DE HQI 14K by Ushio or Phoenix. I run them with lumatek dimmable ballasts.

 

[jda]

Just so you know, I consider a 20k radium on m80 to be more like a 14-15k bulb. Other 20k bulbs are more blue than a 20k radium is.

 

[Graffiti Spot]

I used two large reflectors and cut them and riveted them back together so they would fit my 36" cube when I had it running. I didn't want any shadows so I ran two bulbs and I loved it. So much so that I just put them back up when I moved all my remaining corals into a 100 gallon rubbermaid.

 

[DesertReefT4r]

I ran 2 150w then switched to a single 250w over a 40B that was sps dominated. At 12-14" high I got really good coverage and a good par spread.