So I got a 50w LED in the mail the other day, and I've had a bit of fun playing around with it. I bought it to try a few things out, one is an underwater swimming pool light that i'm designing. Also I would like to try out LED Lighting over my aquariums...

I already have 2 7W LED's over my 2 small tanks. 1 single one over a tank is ok, and does provide plenty of light for plant growth. 2x 7W over 1 tank also works great for plants. And as of tonight Im baking the fish in my 25L tanks with 50W of light over it. The killi's don't appear to mind... yet.

Heres a couple of photos to show ya. (Clickable thumbnails)

The photos dont do it justice to show how bright it is. When fitted over my 200L, Its still brighter than twin 30W tubes with reflectors

Good quality ones seem to work quite well. Cheap ones last a week.

my cheap 7w ones have been going for almost a year now...

how much do they cost to run comparitvly to standard tubes?

Uhhh depends on the wattage of course. I'd say running costs are the same. But the difference is in the lifespan. LED's should last many years, where as a tube doesn't. Initial costs may be more for LED's. But if you are a little bit handy it may even be cheaper... especially when you see how much even a single tube costs now.

Breakdown of my costs:

50W LED $16USD

Circuitry $19USD

Reflector $2USD

So say about $45 nzd for what i had running there.

Heatsink and fan you can salvage from an old computer or will probably cost you $10

Obviously this doesnt have any fancy housing or fitting at this stage... thats still on the to-do list.

Looks good, how do they compare to CFL bulbs?

Running costs are much much lower.

I got some 5050 SMDs that have turned to crap. inconsistant light levels, colours flickering, Why is it always the blue lights that blow first?!? :an!gry

I also have some 5050SMD's of the RGB variety, but they really arent very bright, good for a bit of mood lighting at night but not really much else.

The problem is those also get warm, so ideally they want to be mounted to something that will dissipate the heat. Hot LED's die fast. The cooler to you can keep them, the longer they will last.

What my ultimate plan is, will be to cool the LED's using water from the aquarium. Basically providing free heating during the day. Will of course need to provide a failsafe/feedback system to prevent heating the water beyond a set limit.

I'll probably provide the water flow by means of a small powerhead. 3watts pumping power to save a whole heap on heating sounds like a pretty good deal to me.

Might pay to check the fine print on the waterproof... Some manufacturers idea of waterproof is 1m for half an hour at a time, not half a metre permanently submerged.

Oh yea this water cooled thing is nothign to do with the 5050 type led's, but for larger high power ones. I'll have to design/make all the components.

And it wont be submerged either. Check this link: http://reefbuilders.com/2010/03/19/wate ... ures-heat/

What voltage are you running the HSF at? Small ones can be quite noisy...

I'd be inclined to get a bigger heat sink and a better quality 120/80mm sleeve bearing fan running slowly.

Right now it is 12v, but Im not too concerned about noise at this stage. I can also rig it to 5V or I have a fan speed controller i hook up to it.

I've done a little looking around online, and I'm thinking some aluminium watercooling blocks used in some PC's might be quite a novel and simple solution for cooling the LED's