How many LED's per????

[kwramsey2]

Does anyone have a standard number of LED's per gallon or per foot?? I have a 48" X 10.5" wide (inside) measurements 31 gallon tank. I'm thinking retro LED's is best but how many should I have they have 28 LED's for a 35 gallon I think but also my tank is very narrow so I'm thinking this will be enough. But I could also go with the 42 LED's setup for 48" tanks. What do you guys think? Any tips or ideas for a build would be helpful also.

 

[CaravanShaka]

I am doin 30 LEDs and a 4 bulb T5 over a 48x18 tank. LEDs only i would do at least 36, but i think doing 24 and 2 t5 bubls would cover the entire spectrum better for corals. Just my opinion.


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[kwramsey2]

o and by about 14" deep I forgot to mention that.

 

[matt_longview]

I have a few 48x12x12s and I went with 36 LEDs. They need dimmed heavily even for SPS only tanks. You'd be fine with 24, but I would build them in groups of three close leds, and spread the groups apart.

 

[psteeleb]

for future reference a "rule of thumb" for 3w Cree's or equivalent is 12-15 per sq foot of surface area

 

[kwramsey2]

Ok thanks guys so now that I have that part figured out where do you suggest I order my retro kit from? Im leaning toward steves leds anyone have a pref?

 

[rckrzy1]

@psteeleb wrote:

That seems like a lot . My prism has 18 3w Crees over a 27 g cardiff , about 18x18 and it's more than sufficient , for me it's like 9 per sq foot approx.

 

[matt_longview]

It always depends on what you want to keep at what depth. SPS at 12" doesn't need much. SPS at 30" needs a ton more. Each tank is really unique depending upon size (especially height) and desired stocking.

 

[kwramsey2]

I think I'm more than good with 28 14 blues and 14 whites 4 groups of 6 with 4 blues on a separate drivers for moon light. 48L x 10.5W x 14D but only 12 in of water because of wavers. 12 in away prob u guys think that will do or closer? further???

 

[Tj51]

@kwramsey2 wrote:

If they are dimmable I would think you'd be better off more like 6 - 9 inches and you can always dim the lights. If you mount them to high and have to have the lights on high you won't have the flexibility to adjust based on your corals. I have mine at a height to where I have my whites on about 60 - 75% and if it appears my SPS needs a little more light I can just turn my LEDs up some; much easier then having to lower my lights.

I have seen a lot of people talking about the depth of the tank but if you're growing SPS, the depth of a tank is irreverent; you should be mounting them either near the top of your tank or mid tank at worse, so the only coral that should be affected by the depth of a tank should be the LPS and softies that are placed near the sand bed. If you place your coral near the top, it should be 3 - 4 inches from the top regardless if the tank is 12" deep or 30" deep. So actually there is more "risk" to the corals in a shallow tank as the LPS such as chalices might be to close if the LEDs are to strong.

 

[matt_longview]

It still matters a lot that way. If your tank is 12" deep and you add the same number of leds as you would to a 30" deep tank your lps can only be 12" deep... so they're all gonna lose color or die. You have to add less leds to a shallow tank (depending on stocking).

I completely agree 6-9 inches. I'm assuming you're not planning on optics (which on a tank this shallow is the best choice).

 

[Tj51]

@matt_longview wrote:

I totally agree. I think that people will have to more to ponder with the shallower tanks. The coral that don't like "bright lights" will be something to consider. You will need enough for the SPS but being 12" will lead to problems as stated for the LPS. On the other hand if your tank is deep and the LPS isn't getting enough light, you can always move it up. To me it seems like most of the people are concerned with the deep tanks and the lighting being enough, that's why I pointed out that most of us with SPS will have them mounted near the top regardless of the depth of the tank.

 

[kwramsey2]

Haven't really considered any optics.... Don't really know much about them either. So where would u guys order from?

 

[BrianG]

I say go with Steve's, cost vs efficiency it seems like a greater value. I'm not a total nerd either so it's just my opinion because I have not done 1000 hrs of research, however in what I have studied my findings support my statement. If I did it over again I might fasten crees to Steve's fixtures and use his drivers and power supply.

 

[matt_longview]

Gotcha. I thought you meant it wasn't different in this situation, but you meant primarily for deep tanks.

When you're dealing with shallow tanks you have to flip your stocking strategy from top to bottom to side to side. SPS in the center under the bulk of leds, lps to the sides not directly under them. This way you can still keep a mixed reef.

 

[Tj51]

that will be harder with tanks with center braces, but I'd bet that most "shallow" tank don't have center braces (but that's just a guess, if I'm wrong, don't shoot me)

I'm wondering if people are going to start using more dimmer switches for just that reason. If you have a shallow tank you could keep the whites on the front of your heatsink at a lower level for the LPS that are placed near the sand bed and the lights over the SPS, in this case the back of the heatsink at the higher level that the SPS need. It seems like a lot of stuff to have to control but I assume necessary if you want to have SPS and LPS. My tank is 18" deep and I still have to find overhangs to shield the LPS in my tank.

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[CaravanShaka]

@kwramsey2 wrote:

Having built fixtures using all steves, all cree/meanwell, and steves/meanwell...i find the best combination is Steves white LEDs, Cree blue and royal blue, and meanwell drivers.

Steve's whites aren't as bright as Crees, but people very rarely run whites at max power, so they are worth te $1.50 savings per LED over Cree. The blue's, however, just don't pop the colors like Cree Blues. They are also about the same price, with Steves being a little cheaper right now with his sale. Meanwell is a solid trustworthy driver that is easy to wire and setup...you can't go wrong with it. I have had a few Steve's drivers fail on me for unknown reasons. I use 700ma constant current for blues, and dimmable for whites to control color and intensity.

All of that said, i would still to a combo of t5 or mh with the LEDs. Here is my work in process fixture:

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34 LEDs + 4-bulb T5. 6 steves cool white, 4 steves warm white, 10 cree blue, 5 cree royal, 5 steves royal, 4 rapidLED moonlight kit. Each cluster of 3 LED's has 2 different blues and a white for better color blending. T5's are blue+, coral+, fiji purple, blue+.


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[matt_longview]

That's a sexy little retro Joe. Love the mix... love the bulb and LED choices. Major thumbs up.

 

[kwramsey2]

I'm probably going with steves for now the drivers fail and I'm going to freak out. Lol but nice to know I can always go with I different driver if needed.

 

[niteowl03]

@kwramsey2 wrote:

StevesLEDs with Meanwell drivers would be a better option. The meanwells are a better more reliable driver.