Enough LED's?

I have two 9 watt led strips over a 30g Oceanic Cube with a total of 18 bulbs/watts. This is my first led purchase. I actually ordered the oddysea halide fixture but after reading the fire stories I put it on craigslist before its arrival tuesday and bought these LED. I love the way they look and gonna save a ton on electric compared and it was a total of $130 for 2 9 watt strips, the little ballast thing. My question is, Is this gonna be enough for soft coral, lps, or should I add more....How much is enough but not overdoing it. I have 18 now and can go either 27 or 36??

 

Bump!!

 

You don't really give enough information to make any informed guess. For example, what kind of led strips? Are you planning to keep corals or just fish? if corals what kinds of corals. etc...

I think regardless of your answers, seeing that you were originally planning to use a MH, it's safe to guess that it isn't even close to enough.

LEDs are not really more efficient than metal halides overall (at least based on our current knowledge of coral spectral responses). They can be more efficient at focusing light, depending on the led. This is where the bulk of their efficiency comes from. So, for example, on a rectangular tank, with a MH, your basically wasting 1/2 the light over the sides, as your trying to light a rectangle with something designed to light a square. The leds are designed to light whatever shape you want. So, that may get you a 50% improvement in efficiency there, in some cases.

Other than that, the improvement in efficiency is fairly minor if any. Again this depends on the led and MH your comparing though. So, if you want to get the same output as a 150W MH, for example, very roughly speaking, you'll need about 75W of leds.

Likely you don't really need 150W of MH, so, you can get away with much less. Most people tend to waste a lot of light, corals can only use so much and there rest is wasted. This has become the norm for MH lighting and a major reason why LEDs seem so much more efficient. You get in that energy conserving mentality and then only use what you actually need.

Regardless, the smallest MH is 70W and 18W of leds isn't going to be anywhere close to the output of a 70W MH. That's all I can tell you based on the information you've provided so far.

 

Thank you for your informative answer. It is a 30 gallon cube. The LED's are on a 9 watt 12" strip. I went and bought one more, one actinic, one 50/50 and one white and the tank is very well lit as the led are sitting on top of the tank on a glass lid with no light wasted as would of been the case with MH sittin higher due to the heat issue. Total of 27bulbs/27 watts over a 20"L x 18"W x 21"H tank. I would like to keep lps, zoas, ricordeas, etc

 

What kind/brand of leds though? Some leds are 0.5W, others 1W, others 3W, per led. So, if the fixture, is 9W, it could be 3x3W or 9x1W etc... Higher watt leds tend to be more efficient and penetrate better. Also, different led strips use different lenses. 18" is a fair amount of water to penetrate. So, these are important questions.