My LED lighting seems very "Dim" in comparison to MHa's

[Lewis N Sophie]

Hi,
I've just replaced my arcadia 2*250w metal halides + 2 T5's with:
4 TMC Aquaray 1000HD (2* Reef white, 2*Marine white) and 2 * Reef white Aquaray 600 strips.

Not impressed so far is probably an understatement. My metal halides gave a broad spread of yellow to white light with the T5's giving the blue hue which continued after the MH's went off. Of course I don't expect the LED's to match the day/night cycles but I did expect some decent light from them.

Two small sections of my tank have some white light, the rest is grey or in complete shadow.

Is this the norm? I've spent around £1300(2000$) ish and planed to spend a bit more, I have a tank which is 4ft long but only 18 inches wide so loaded the hood as much as I could and have about 3 inches from the water surface to the LED's.

I'd be interested in any thoughts or opinions, I can only think that I may need to raise the lights significantly but it's an expensive thing to try on a guess.

Many thanks in advance

Lewis

 

[Lewis N Sophie]

As you can see, the soft corals on the left and right have a focused white point of light and the rest is dim. Since installing, there seems to be a green and red cyano outbreak which I've not suffered from in some time, I'm assuming these are low-light loving algaes?

Thanks again

Lewis

 

[chipmunkofdoom2]

Well, you replaced 500w of one type of lighting with around 140w of a completely different type of lighting.. it's probably going to look a little different. It sounds an awful lot like you're insinuating the LEDs are at fault here, and I'm not trying to add insult to injury... but it sounds like you didn't do your homework. LEDs and MH are completely different lighting technologies.

A few things to consider:

1. What is your tank size? LEDs simply don't do well without lots of coverage, tweaking and configuration on large tanks. This is flaw of LEDs that's been recognized from the beginning.

2. One of the reasons LEDs are able to be so efficient is because they are a point light source, like miniature spotlights. They light the area underneath them very well, but light drops off substantially after that. Instead of lighting your corners with high PAR light, you're only lighting the areas you need. That's part of the savings.

3. Have you tested each light source with a PAR meter? Everyone says that LEDs are just as strong as MH when configured properly, but that doesn't mean they'll appear to be "brighter". That means that the PAR (photosynthetically available radiation, what corals feed off of) outputs will be similar. We have clocks to tell time, speedometers to tell speed, and PAR meters to measure light output because the human eye is a horribly inaccurate piece of measuring equipment.

4. This seems like a good time and place to remind everyone that you are getting exactly what you pay for when you buy LEDs, but you're not getting a more powerful light source. The biggest flaw of the consumer is the belief that an increased cost must automatically mean you're getting more. With LEDs, this is true, but it's not in the light intensity department. You're getting lights as powerful (PAR output, not necessarily visible light) as MH, you're getting diodes that will last around 11-14 years of 8 hours a day operation (no $120+ bulb costs every 6-18 months), and you're using less electricity and producing less heat, meaning you might not need a chiller if you already have one. So, if you're feeling cheated because LEDs are not magnitudes brighter than MH, don't be... you're getting exactly what you pay for.

If you are unhappy with the LEDs, return them.. but there is likely nothing wrong with the LEDs. For large tanks, you need a prohibitively expensive amount of lights and with a 4 foot long tank, that sounds like what you might have. These are the caveats of LEDs. If you plan to keep the LEDs and perhaps even add more, I would do some serious research as to how much you will need and what kind of light you're going to get. You'll probably never have the same look as MH, but then again you won't have to change bulbs for 11 years and your power consumption will likely be more than halved. The choice is yours, but it sounds like you already have your mind made up that LEDs are snake oil.. I think you'll find it difficult to be satisfied with their output even if you add more.

 

[Lewis N Sophie]

Well, you replaced 500w of one type of lighting with around 140w of a completely different type of lighting..

Thanks for taking the time to write such a detailed response. I did research quite a lot about how much lighting to replace my MH's with based on the size of my tank and the corals I do keep and would keep in the future.

My question is around visible light and brightness rather than suitability for the task (or at least the former question spawned the latter). Without purchasing the lights and putting them into a tank I'm very familiar with it's very difficult to know what they will look like, where dark spots will appear and what other changes may need to be made. My question is to other LED owners or those with knowledge of LEDS "Is this normal, are there downsides to this and if so, is there mitigation".

References/Links used as my investigations:
General info on lighting and useful par/lux/PUR: http://www.americanaquariumproducts.com/Aquarium_Lighting.html
Manufacturer docs on the lighting purchased: http://www.tmc-ltd.co.uk/data/aquabeam1000hd-par.pdf, http://www.tmc-ltd.co.uk/data/led-spectra.pdf, http://www.tmc-ltd.co.uk/data/aquabeam600ultra-selection.pdf, http://www.swelluk.com/pdfs/AquaRay-User-Guide FINAL-2.pdf

I don't have a par/lux meter which is a good point, I'll get one. I can then compare.

1) My tank is 4ft long, 2ft deep and 18inches front to back. When you refer to tweaking and configuration, I have bought commercial aquarium lighting units with no configurable parts. Do you refer simply to placement? If so, I have followed (and in fact over-specc'd) the manufacturers recommendation.
2)Yep, as part of my pre-purchase investigations, this was one of the first points I picked up on. As a light, it's point focus rather than spread like bulbs. It's very difficult for a manufacturer to explain and for me to therefore understand what this translates to in a tank. Is it Xmm spread at 0.Ym distance?
3)As above, another good point well made
4)I don't feel cheated, I do still feel under-knowledged (new word). I'm looking for further understanding from people with the benefit of experience already gained.

I still have the Metal halides, I still have other tanks, as an experiment it's going well. Perhaps I'll consider two small T5's to satisfy my eyes as well as my corals.....or perhaps not.

Thanks again, any other opinions would be very much appreciated also.

 

[steved13]

1 thing that COD2 (I hope you don't mind the acronym) touched on but might help with a little more...MH and LED are both point light source, however MH is a much larger "point" and with reflectors it makes it even larger still. The larger the source the more "spread" of the light and the less shadowing. As COD2 said LEDs are like little spotlights and depending on the optics can be very directional. My guess is that is what you are noticing. Think of it as lighting a large area with spot lights, if you put the light closer, it's much brighter but less coverage, further away you get more coverage but it might not be bright enough, so you'd need an additional light

You can tweak them with placement, raising them provides more spread, but less penetration. You may need additional LEDs to get the coverage you looking for.

 

[BigAl07]

By purchasing a commercial unit you're pretty confined to what you can and can not "Tweak". If you want to stick with the your existing fixture and just add something there are some fiarly impressive smallish strip units you can use to just add some "Viewable" light. If you want to really take control you can return your current fixture and get something that's more "Modular" like the AI Sol unit. You buy it in "Blocks" and just keep adding more as you need/want them.

Good luck and I can't wait to hear what your PAR test results are.

 

[Lewis N Sophie]

By purchasing a commercial unit you're pretty confined to what you can and can not "Tweak". If you want to stick with the your existing fixture and just add something there are some fiarly impressive smallish strip units you can use to just add some "Viewable" light. If you want to really take control you can return your current fixture and get something that's more "Modular" like the AI Sol unit. You buy it in "Blocks" and just keep adding more as you need/want them.

Good luck and I can't wait to hear what your PAR test results are.

Hi Al, thanks for the reply. I bought a commercial unit mainly due to not having an electronically minded bone in my body I think I have two further requirements. One to add some visible light during the day (any links to the fixtures you refer to?). The second is to add some actinic/blue moonlighting, both of which could probably be satisfied with some further units from the same manufacturer although again if you have any other links (particularly ones where they ship or are available in the UK) I'd be very grateful.

Thanks again

 

[radicalxraiin]

Do i need Special lighting for LiveRock?

 

[Robzilla]

LEDs give off a dimmer/darker look to the eye, especially coming from such a strong light source before that. I thought the same thing when I got mine but it is natural to think that and you will get used to and eventually love them. Since the lights point straight down, you will have more shade in your tank causing it to look dimmer. I would wait a few weeks and see if you are still not happy. Make sure you measure the PAR too to make sure you didn't get a fluke unit.