This sounds like a really noob question and I have a hard time asking it because in general I would be able to answer this question for most people. However, I'm using LED's for the first time and each unit (two of them) has individual dimmers for actinics and "daylight" spectrum. It's hard for me to tell where I should be keeping my dimmers and I don't have any corals in this new tank yet to experiment with. Is this basically a job for a PAR meter?
How much light is enough?
- Thread starter sfoister
- Start date
MrHarvard
"ship it"
Well yes and no. I am having the same issues currently and it almost makes me wish I had T5s again. .lol.. The first thing I would do is find out what the "advertised" par is for the led units you have and calculate that with the size and depth of your tank. This should give you a good starting point. To move on from there your going to either need a par meter or some corals in your tank so you can see how they respond to your settings. Of course if you re post this question and list exactly what size tank you have and what led units you have you may get feedback from others running the same equipment or at least something similar. Hopefully this helps get you closer to your amswer.
oblio
New member
Mr Harvard has a good point, add your specifics to the post and I'm sure people will chime in with some advice.
include: light specifics, tank specifications.
As a general rule though if you don't find any answers is "too little light is better than to much" so start lower then gradually increase.
include: light specifics, tank specifications.
As a general rule though if you don't find any answers is "too little light is better than to much" so start lower then gradually increase.
I have two of these over a standard sized 90 gallon tank. (48 x 18 x 25)
http://www.ebay.com/itm/165W-Dimmab...757?pt=LH_DefaultDomain_0&hash=item3a8e50f63d
I've seen quite a few photos of tanks running these fixtures with all types of corals, SPS, LPS, soft, etc... But no one I talk to that has them can tell me much about the actual light output, seems like everyone is just using the trial and error method.
http://www.ebay.com/itm/165W-Dimmab...757?pt=LH_DefaultDomain_0&hash=item3a8e50f63d
I've seen quite a few photos of tanks running these fixtures with all types of corals, SPS, LPS, soft, etc... But no one I talk to that has them can tell me much about the actual light output, seems like everyone is just using the trial and error method.
Webmanny
Active member
I know this will start a debate and potentially get me a few insults, as many will disagree with what I'm about to say here, but here goes nothing.
This is just my two cents and please note that I do not own one of these lights, but I am a big fan of LEDs and I have made a few lights using these same diodes (3W) myself.
Based on what you have shared, you have 330 watts of light over your 90 gallon tank. This means that you are running at about 3.6 watts per gallon.
Many books I have read about aquariums have always used the recommended watts per gallon method and I use it today with great success.
In my opinion, 3.6 watts per gallon is a bit low and if you plan on having SPS corals, you will need to bring that number closer to 8 watts per gallon, so you can play with the colors/intensity per channel and have a greater chance for success.
Many will say that there is no way you can grow SPS corals with LEDs... I totally disagree, but everyone is entitled to their opinion and this is mine.
Recommendations:
This is just my two cents and please note that I do not own one of these lights, but I am a big fan of LEDs and I have made a few lights using these same diodes (3W) myself.
Based on what you have shared, you have 330 watts of light over your 90 gallon tank. This means that you are running at about 3.6 watts per gallon.
Many books I have read about aquariums have always used the recommended watts per gallon method and I use it today with great success.
In my opinion, 3.6 watts per gallon is a bit low and if you plan on having SPS corals, you will need to bring that number closer to 8 watts per gallon, so you can play with the colors/intensity per channel and have a greater chance for success.
Many will say that there is no way you can grow SPS corals with LEDs... I totally disagree, but everyone is entitled to their opinion and this is mine.
Recommendations:
- Get a third light. This will bring you to 5.5 watts per gallon and allow you to dim the lights a bit and get longer life out of them.
- Get a PAR sensor. You can buy just the sensor and use it with your electric multimeter or join the club and they can lend you the club's PAR meter.
- Go to the club meetings, so you can see other users setups and compare colors and intensity to that of your tank.
- Play with the intensity of each channel on your LED lights until you get similar colors to those you have seen in other tanks.
hobbzz
How do I change this?
No offense intended to anyone here, but watts per gallon is a very old and outdated way to configure a lighting system. It's useless these days because it doesn't take efficiency into account. Back when the watts per gallon rule was "invented" 30 or so years ago all lighting systems were about the same efficiency wise. With leds especially, simply adding optics and keeping the leds at teh same output can increase the par exponentially. A perfect example, 20 inches away from my fixture with no additional optics (with 120 degree built in lenses) I get about 50 par-100. With the 60 degree optics I have on them I get 500-550 at that same level and 100-150 on the bottom another 8" inches down.
That being said, I would start at around 30% and borrow/buy a par meter. Keep them around 4-6" off the water. You'll definitely have to increase the output once you get a par meter, and maybe move them closer to the water, but you don't want to start at 100% and find spots toward the top burning coral because it's too high. Two of those units should be fine unless you want to grow sps on the bottom and have corals packed into your tank all the way to the edge touching the glass.
That being said, I would start at around 30% and borrow/buy a par meter. Keep them around 4-6" off the water. You'll definitely have to increase the output once you get a par meter, and maybe move them closer to the water, but you don't want to start at 100% and find spots toward the top burning coral because it's too high. Two of those units should be fine unless you want to grow sps on the bottom and have corals packed into your tank all the way to the edge touching the glass.
Watts per gallon is something I am familiar with, and I have not used that rule in probably a decade. That being said, I've never had dimmers on my lights so that's the reason for the question. I guess the answer is just get a couple frags and start experimenting. Also, I will likely join the club at some point, so I may also just borrow the meter at some point.
These fixtures have 90 degree lenses, so I'm keeping them about 11 inches from the water surface currently.
I'm going to keep LPS mostly with some mixed softies. I could probably keep SPS with these lights, as I have seen other doing it but honestly at that point it becomes a water quality issue. I don't want to keep such an intensely clean tank. Who is going to read to my toddler if my hands are always in the tank?
Thanks everyone
These fixtures have 90 degree lenses, so I'm keeping them about 11 inches from the water surface currently.
I'm going to keep LPS mostly with some mixed softies. I could probably keep SPS with these lights, as I have seen other doing it but honestly at that point it becomes a water quality issue. I don't want to keep such an intensely clean tank. Who is going to read to my toddler if my hands are always in the tank?
Thanks everyone
