These LED's just aren't cutting it. Or - are they?

[Jakegr]

Originally Posted by Ron99

As for the topic of this thread, bleaching does indicate too much light. Blue is high in PAR in the spectrum that corals utilize so turning them down or raising your fixture will help. And you need to give the corals time to acclimate to the new light intensity. They won't change overnight. .

Just a note - blue light is not higher in PAR than red light. PAR is measured as umol photons 400-700 nm / m^2 / s. The PAR from 20 photons of blue light is equal to 20 photons of red light. I think you mean blue photons contain more energy than red photons, which is completely true. This is a bit of weakness when relying on PAR as your sole indication of light quality... it values all photons between 400-700 nm equally.

Also, re: growing photosynthetic organisms under monochromatic light - there are usually a lot of problems with that as blue light, red light, and far red light play many non-photosynthetic physiological roles. You are completely right about growing corals under white LEDs only as that is not monochromatic light. Growing them under only blue or only red probably is not a good idea for the health of the coral.

Also, the PAR meters used by hobbyists miss blue photons and tend to underestimate PAR in fixtures with a lot of blue light.

I think a lot of misconceptions about LED lighting are due to hobbyists having misconceptions about the nature of light and its measurement.

[Ron99]

I doubt that those really cheap generic fixtures are using meanwell drivers or decent LEDs. You just can't get them at that price point. Some other slightly more expensive fixtures may be using Bridgelux LEDs (which are pretty good) and possibly Meanwell drivers. Some may even be using Cree emitters. But there are also different levels within Cree LEDs for example because LED manufacturers bin their LEDs according to output and colour so the higher bins will have higher output and colours closer to their ideal rating. Higher bins are more expensive. So cheaper fixtures are likely using lower bins of LEDs than the more expensive ones.

Can you get good results with less expensive fixtures? Absolutely. But you might not have longevity, maximal output if you need it for a deeper tank, or just general build quality. They have to cut some corners if they are keeping prices down, especially with the really cheap fixtures.

Jakegr: you are correct and I suppose I didn't explain myself fully or clearly. What I meant to say was that blue LEDs emit close to one of the chlorophyll absorbance peaks (as well as the absorbance peak of carotenoids which may or may not be important in corals) so they are providing lots of PAR to the corals even though they may look dim to our eye. So having them run at high output could be bleaching out your corals even though they may seem dim to you.

And it is well known that PAR meters underestimate the PAR at the blue end of the spectrum as most were designed to be used for measuring light for terrestrial applications rather than under water.

[jason604]

I'm happy with my "cheap" LEDs. Thaotronic dimmable led version seems to have tons of great review.cant say the same for there other fixtures. Boy it must feel dumb paying up to 10x as much as I did and get about same results =). Being on student budget these were the best choice for me. I have my blues at 60% and whites at 50%. Should I crank it to full blast?

[SeaHorse_Fanatic]

Originally Posted by jason604

I have my blues at 60% and whites at 50%. Should I crank it to full blast?

If that is working well for your corals, then keep it at that level. You can slowly increase it if you want, but for me, I would treat this as a "if it ain't broke, don't fix it" scenario.

[The Guy]

Originally Posted by SeaHorse_Fanatic

If that is working well for your corals, then keep it at that level. You can slowly increase it if you want, but for me, I would treat this as a "if it ain't broke, don't fix it" scenario.

Yep, I agree totally, I'm about to set up a 60 g cube tank and am going to use a 90 watt Pharos, which I guess is considered a "cheap Chinese knockoff" but let me tell you it's got a great review if you read up on them. I would say not to paint all overseas led's with the same brush!

[bowkry]

I just set up a 60 gal I am running a pharos over it, so far I like it. I am putting my first corals in today, so we will see how it does.

[Ron99]

I'm not saying that the cheap fixtures don't work. Of course they will and people are happy with them for now. But talk to me after two years of using them when the LEDs are dimming or burning out because of cheaper drivers or poor thermal management. Or the drivers themselves are dying or the power supplies are dying, or worse, catching fire. I know that sounds alarmist but recently I've seen a different affordable chinese product which works well, is a fraction of the price of competing european products but has power supplies that sometimes fail in scary ways.

You do get what you pay for. If you want to buy something at a lower price but have to replace it every two years that's your choice. I had a similar discussion with someone recently that was the whole Apple vs. cheaper PC one. She said that she could buy a PC laptop with the same specs as an Apple one for much less. While that's true, you pay for quality components and craftmanship. I'm currently typing this on my 6 year old Macbook Pro. It still runs like a champ espite having been very well used and dropped numerous times (to the point it has several dents and the top bezel separating from the body) etc. I don't know too many people who can say the same about their budget PC laptops.

I completely get trying to do things on a budget and I also agree that some of the high end fixtures are probably overpriced for what they are. But you generally do get what you pay for and I'm pretty sure you will see far more people still using their Vertex Illumina 5 or 6 years from now than you will their Taotronics or Pharos etc.