What's Sanjay's Conclusion?

[jimidalock]

I couldn't stay for Sanjay's lecture I had to go to work. Did he say that LED's are as good as my MH's? Will SPS grow as well?
P.S. Thanks to everyone involved for putting on a great event!

 

[Josh]

Ha! I double dare you to ask Sanjay a question like that. There was not a straight answer, basically it comes down to:

Yes you can grow SPS, the light intensity is equivalent (in fact it is more than MH in certain areas so you have to be careful you don't burn the coral)
No it is not a straight replacement for MH due to issues with spread (coverage in your tank) For the fixtures tested the intensity was greater in the central areas but very cone shaped as the light pours into the tank from the reflector system.
No the color is not equivalent due to design of many LED systems (they don't all allow color tuning and the LEDs themselves do not fully replicate the color distribution of MH).

 

[tosiek]

Plus, the fact that LED's are changing every 3-6 months to something newer and better was also mentioned.

I don't remember Sanjay getting into pricing and its comparison with MH, and if the savings on electric justifies getting one. Or their lifespan and how much they drop in intensity over a certain number of hours.

 

[jimidalock]

Thanks for the update Guy's!!!

 

[sanjay]

Josh:

Great summary. You were paying attention.

Yes, I should include a slide talking about a list of cost factors to consider when making the decision.

sanjay.

 

[jaa1456]

Not trying to stir the pot or start any trouble, but those are the conclusions you came up with? I did not attend the swap but I already know that from just reading about the fixtures and comparing the ones I see in the LFS's

 

[joseney21]

a way to resolve some of those issues (when going the DIY route) would be to use wider optics on the outer edges of the fixture where you want more spread to further areas. You can also try wiring the leds in a way so that the ones on center are driven at a lower current compared to the ones in the outer edges of a fixture, this might give you more even par numbers all around. I might do some of this when i make my own...

 

[ming]

a way to resolve some of those issues (when going the DIY route) would be to use wider optics on the outer edges of the fixture where you want more spread to further areas. You can also try wiring the leds in a way so that the ones on center are driven at a lower current compared to the ones in the outer edges of a fixture, this might give you more even par numbers all around. I might do some of this when i make my own...

I am instead going with wider optics in the center, and more narrow optics on the side to give a more even spread.

 

[Dace]

Just a quick comment . I really like the way the LED fixtures look nice and thin, take up little room, Easy to hang, Don,t give off any heat and will definitely switch to LED for all our business tanks as it will be cost effective for us. But as of now i don't think i will ever change out my MH from my display tank to LED Fixtures. I don't know why but i just don't think they make sps look good. I love what they do for lps, But i can supplement the same look they do for lps by adding power brights to my system.. I still love my MH look... Maybe when more question get and answered and a little more research is done. Just not now.

 

[pecan2phat]

The problem is that you cannot judge one LED fixture to be true of all LED fixtures. I have seen where colors are washed out of both dim & bright fixtures. When you utilize focal optics, you get a nice balance of some shadowing which looks more natural then without focal optics. Then there is the quandry that to utilize focal optics, the lamp is probably not utilizing 1W LEDs.

 

[NYreefNoob]

missed that lecture also, sajay how long have you been using led's and what brands do you have and or tested ?

 

[greg 45]

sanjay you stated color is only for the eye . you stated par is more important.
What is the correct par that i am looking for.
should i purchase a par meeter.

 

[ming]

sanjay you stated color is only for the eye . you stated par is more important.
What is the correct par that i am looking for.
should i purchase a par meeter.

PAR is how much of the light can be used by photosynthesis.
The correct par is depending on how much the coral needs. not all corals need same amount of lighting.

 

[prattreef]

I think Sanjay's personal rule of thumb is that PAR of at least 100 on the bottom of the tank is sufficient to grow most corals throughout the tank--obviously some do better higher up and others lower down etc.

 

[juiceguy]

I think he said he had switched all of his personal tanks over to LED but the big tank at Penn St. is still halide just because of the initial cost of converting to LED is still up there for a tank that size.

As far as Par goes, he said that 100-300 is good for LPS, softies and some monti's. for sps and monti's you are looking to get anywhere from 300-500 and those really light loving sps you are looking for 500-700 range.

 

[prattreef]

His large tank at home ( the one you all see photos of) is still running MH as well. All his smaller systems are now LED.

 

[greg 45]

I have a anemone tank with Gigantea anemones.
How do you convert lux / lumens to par
or is the meter called a lux meter
thanks

 

[jaa1456]

I have seen these debates before. This is about 6 years ago or so. VHO will replace MH. Well no it didn't, The new T8 will replace MH um no it didn't. Then there was what a T12 I think? same results. Now T5 will replace MH nope it didn't either. Leds will now replace MH, we will have to wait and see. The LED fixtures are so far from where they need to be to even be consider a full replacement. I love the concept and Idea behind them, but the knowledge and materials need to be improved. I see to many high priced as well as lower priced LEDs with burnt out banks and non working lights. Who wants to pay 700 for a small fixture just to have bulbs burn out that are supposed to last for 10,000 hours. I have a set of LEDs on one light and I think there are 2 left running the rest are burnt out. 5 months old and thats what the result is? The companies response, we will send you new bulbs at 5 dollars apiece, you will have to remove the old bulbs and solder the new ones in. What???? They really need to fix the problems before letting these fixtures out.

 

[SevTT]

I have a anemone tank with Gigantea anemones.
How do you convert lux / lumens to par
or is the meter called a lux meter
thanks

Lux and PAR are two completely different things, though it doesn't seem so at first. Lux is based upon the total visual brightness of a light source. PAR (which stands for Photosynthetically Active Radiation) is a measure of the intensity of light which is useful for photosynthetic purposes. (Chlorophyll only works with a few very specific wavelengths of light, and, while photosynthetic critters have a few tricks up their sleeves to broaden that band, only a limited amount of any light source is actually useful.)

Furthermore, your light source isn't the only problem. Dissolved organic compounds in your tank may absorb wavelengths of light that're most useful for photosynthesis, but have only a limited effect on the actual appearance of light in the tank.

As to what individual corals need -- there're wide ranges, and some adaptability, depending on the individual species (and sometimes individual coral.) Too little light and the coral starves, too much and it will experience photoinhibition and damage to the photosynthetic pathway, which will lead to the same thing.

TL;DR summation: Just see what fixtures and products other people are successful with over tanks of similar size as your own, follow roughly similar coral placement (while watching the actual coral for reactions,) and you should be fine.

 

[Josh]

Not trying to stir the pot or start any trouble, but those are the conclusions you came up with? I did not attend the swap but I already know that from just reading about the fixtures and comparing the ones I see in the LFS's

He measured PAR readings at different heights in the tank over every square inch to compute the intensity spread. The results were pretty clear. One thing about Sanjay's presentations (which irritates people who just want a quick answer and aren't interested in understanding the topic) is that it is based on facts and data and not personal opinion. You may very well like the look of LEDs from what you see in the LFS but how many LFSs are running LEDs over their show tanks. Putting them over frag tanks makes the corals look pretty nice but if you want them to live and grow under that lighting over months you need to consider all the facts.