Throughts and Recommendations on LED lighting

[Groundfury]

To start my tank is 72x28x18 150gal with 2 braces. I am running 3x250 MH's and a Super actinic VHO. I want to experiment with LED's to see how things go, but I see I have a few options to choose from. I see I have LED's from 1w all the way to 100W + but kind of torn on what to use. I would like to keep the number of LED's to as few as I can but make sure I get good coverage and depth.

LED's per brace opening
I am looking at using Epistar LEd's. I'm not sure if I want to go with 20000k and Royal Blue combo on one LED or go with 20000k and Royal Blue on separate LEd's. Now another question is want wattage led's to use. Do i use a few 20watter, even fewer 30watter, or maybe just use one 50 or 100 watt.

Drivers
I am using a Apex controller and would like to be able to dim my leds from the controller. My thought is to use some buckpucks so that I can dim the leds. This experiment I am trying to keep the cost down to start with but it seems that to power the led's can get out of control fast. I have option to get drivers that can drive a few leds for cheap but I loss the option to dim the led's. If i go with buckpuck or something like that to get my dimming option back I am now looking at a power supply at about $50 then drivers at $20 each and still can only run a few led's. Now if I was to get a 36v power supply and a buckpuck that is 36v x 1400mv then I should be able to run 12v x 700mv leds in 3 in series and 2 series in parallel so that would be 3x2 on one buckpuck.

Let me know what you guys think and any recommendations would be great.

 

[BonsaiNut]

You're thinking about lighting the wrong way. Don't think watts - think spectral intensity. In other words, you need to understand how much light and what kind of light each LED generates. After you design a system that creates the light that you need - THEN you add up the watts to see how much electricity the system uses. Right now it's like you're trying to buy a race car based on its fuel efficiency. What if there were two LED's that both generated the exact same light, but one used 1 watt and the other used 2 watts?

 

[Groundfury]

Ok i guess that is the big picture question here, what is the intensity or lums that I will need for a tank of my size. I know that a 20w led as around 1500LM and goes up from there. I am not sure how to translate the lums from MH to LED lums. I know that I want to use the 20000k spectrum and if needed supplement with the 450nm spectrum. I am aware that LED's may not be true 20000k spectrum so I am taking that into consideration.

So from another post that I read a recommendation was made on a 4ft tank to make 4 rows with leds spaced at 2.5" apart, and this should be enough to grow anything put in the tank. So if i do the math on that and say that each opening on my tank is around 22x15. So if i take 22/2.5=8.8 x 4=35.2 LED's per opening. Now if I take 150lm(3wleds) x 35Led's =5250lms per opening on my tank. So that's 35 3wleds or 3.5 20w or 1.16 50wLED's. now I'm sure im over thinking this and my math may be off but I wanted to see real world what the best wattage and number of leds would be the best to experiment with and get the biggest bang for the buck.

 

[jgsalwater]

Best buy for the money. I would buy three or four 60w Crees. Look at my home page for photos and details. They will give you plenty of light. I would get them with dual controllers for each light so you can tune in the color and phase in the lighting with your Apex. I added a couple of controllable PAR38 LEDS bulbs to spotlight a few coral in my tank to look like shafts of sunlight.