Help Me Pick a Light Fixture...

[VR28man]

So, I'll be hopefully getting a new tank this summer, and am thinking about lighting. Main option will be either a 36x18x20 tank (57gallon) or 48x18x20 (standard 75 gallon). (as an aside, IMO lighting them is just the same, except you need an extra pendant or an addition 12" of T5)

So I'm thinking how to light it. I've been dissatisfied with Kessils - they look great, IME they grow zoas, softies, war corals, monticaps perfectly well. But a lot of my monti digis and acros have become quite obviously shaded. (intensity on a 360 and 160 mounted 12 inches over the tank gets up to 100%, 400 measured PAR in the water right under the 360, though around 100 by the time I get to the bottom of the tank where my green slimer is).

Since I want my next tank to be a acro-heavy upper fore reef biotope, I've started thinking about lights. I've gotten a cheap dual t5 fixture (one ATI Coral Plus and one Aquablue) for my current tank and I definitely notice much more even lighting in the tank. (not anywhere near as cool to the human eye as the Kessils, though). I think the corals are reacting well to the T5s so far, after two weeks.

But, reading a lot of @jda and @BoomCorals I've started to think about halides, either T5+halide or just halides.

However, with just halides I'm still worried about shading from two strong, concentrated light sources, though admittedly the pendants should help diffuse the light.

Anyway, I've looked so far with a single vendor just to simply my thinking (before I compare the offerings from other vendors), and am thinking of the options above. People's thoughts would be welcome!

Also, for a 20" deep tank, what wattage MH would people recommend? 200? 400?

 

[Ron Reefman]

The MH lighting will work, just be prepared for the heat and the cost of good MH bulbs every 2 years.

BTW, I had a 120g tank (20" deep) full of sps (50% or more were Acros) lit by Photon V2 led fixtures. And I didn't have to run them near 100% power to get good growth and I sold a lot of sps frags over a couple of years before a run away chiller killed all the branching and plating sps corals in one night. The water temp got down below 60 degrees.

 

[jda]

Be looking at 150w HQI on m80 ballasts or 250w MH. No need for 400w on a tank like that. Heavy acropora might be more towards 250w, but if you want to run some T5s too, then 150w would probably be fine. Hamilton is a good US company that is very helpful - call them if you have an questions.

2x 150w Halides are low wattage and also stay pretty cool. They have good bulbs choices and do a good job. 14k Phoenix is a best-of-breed type of bulb for 150w HQI with great color, pop and growth.

I have 5x Halides over a 40g tank and a simple Vornado fan keeps the temp from even moving. Other than July and August, the heat is a blessing and my heaters run way less. I am in Colorado where it does get hot, but humidity is low. There are climates, like South Florida and the Mojave, that have too much humidity and/or too much heat for fans to work alone, but if you live outside of these areas, you might like the heat and evaporation. I have a friend that lives in Phoenix and with the AC on, they like how his tank keeps from getting static on all of their clothes from too dry of conditions. Heat can be real. It also can be easily solved, depending on where you live (you can update your profile with this). Open top tanks with pendant type of Halides are easier to keep cool. Hoods can be a problem, even with T5s or LEDs where all of the heat stays trapped.

Think of a MH light source as big as the reflector is. I have some 16x16 inch reflectors and they put out light from all of it... nearly now shadows anywhere. Since it scatters, it can also bounce off of clean glass, but not so much glass covered with coralline.

 

[jda]

Also, I would do two MH bulbs in a 3 foot fixture.... even with T5s. This is another reason why 150w might work well since they are covering a small area.

 

[reacclimating 2 the hobby]

Agree with Hamilton, although I didn't have great success with their customer service, the fixture was very affordable and works great now that I figured out I had a bad bulb at first. Mh/T5 and I'd agree again with two bulbs.

 

[jda]

I guess that I should point out that I use MH alone. I am not a fan of the "best of both worlds" paradigm and often have found that serving two masters is serving none, or that teams with two quarterbacks really have none. I decide what I want and then go all-in... in life and also in the hobby. In any case, I just spend all of my electricity and money on MH alone since I feel that it is the best. You can have a lot of success with just MH, or just T5s, or a combo. I don't care at all about dusk/dawn, dimming or the black-light look and just run for 10-11 hours with 250w HQI with on/off light timers. If you care about that stuff, then a combo light works out great... it is just not for me.

I do have 2x T5s in a fixture over a frag tank and I run GE 6500k in them for max growth and color rendering. I would probably not do this over a display and would probably run bluer bulbs if I were to venture into this paradigm.

Nobody can really help you decide what is best for you... we can only offer suggestions and then you can decide for yourself. This is the only way to be successful.

Also, about heat... you might live in an area where you have to run a chiller regardless, so just plan ahead. Ron had an unfortunate chiller failure with LEDs... but he is in a hard climate to keep a tank cool no matter what you do. When I ran a chiller in Missouri, I kept it outside and that helped a lot - it did cost about 50 cents a day on my kill-a-watt to run it. I brought it inside in the winter and put it in storage. I later learned not to use small computer or "tank" type of fans and to get a real tool for the job and have not run the chillers since.

 

[VR28man]

Thanks, all! A lot to chew on. It seems the only Hamilton fixture that's dual ended for the 250w hqi Phoenix is the Cayman sun (but it comes with it own bulbs), and possibly the Bimini sun mini fixture. (I'd have to ask them)

Ultimately, I do have to choose between MH, T5, LED, or combos therof. I'm extremely happy with T5s for far* for my current tank (aqueon 29g), but again I'm upgrading tanks and am thinking of the next tank. I definitely want a light with more even spread than the kessils. The light bars (e.g. Orphek) were tempting, as were Ron's Photons. But oddly enough, a new Hamilton fixture seems to me is priced very competitively with the LEDs of comparable coverage. A high quality T5 fixture like the ATI sunpower is also comparably priced.

So in the end, it seems to me the main difference is heat, area of coverage and the nature of coverage. For heat, I live in Virginia; the house is 73 degrees or so year round - but the sun room a few feet away gets into the 90s in the summer. I am concerned about heat to a degree, something I never worried about with the Kessils. Area of coverage is published by the manufacturer. But nature of coverage is more subjective. Though I'm getting more par from the Kessil 360 than my current T5, the T5 spreads the light much more evenly.

Anyway, apologies for rambling. I'm leaning strongly towards 2-3 250 MH pendants (depending on the length of the tank), or something like the ATI sunpower. If I go with the corner tank, I probably will mount two pendants atop my main coral growing areas and supplement with an LED which can cover the majority of the tank. (e.g. my Kessil) for supplementary coverage. And for looks.

*As an aside, the T5s have done wonders for my acros. More on that in a separate thread.

 

[VR28man]

Got some feedback back from Hamilton which may be useful for folks.

Each Hamilton Bali Sun (15x11x5 inch pendant) will cover 2-3 feet of tank length depending on how high you hang it above the water.

[they] recommend starting it at around 8” – 12” above the water and lowering or raising it depending on your light needs and the amount of heat transfer (which should be minimal since it is being suspended above the water). Start there and see how your corals respond, then raise or lower it. You can go down to 6” above. Most customers suspend it about 12” above. Much of it will depend on what is in your tank.

Same applies for the Bimini Sun. (12x11x2.5 inch compact pendant; the reflector is notably smaller than the whole pendant) Bimini gives less of a footprint. It is more concentrated. Bali Sun gives a larger footprint of light.

They also recommend 175 or 250w 14k bulb for tank depth of 24"- 48". (interestingly enough, a 175w 6500k bulb is recommended for 17-36"). 1000w 14k bulbs are for 48"- 65" (!) deep tanks.

So it seems for most 36" tanks, one Bali Sun would be enough. The 48" tank might take two lower on the water, or one plus two small supplemental lights.