A Lighting System for New 180G

[herring_fish]

I asked similar questions a couple of years ago but after some setbacks, I am finally close to stocking my tank. I think that there is more experience with LED's now so I will update my setup and the questions.

I have a 180 gallon display tank that is 31 inches deep and will be stocked with SPS, in a highly mixed environment. Hopefully this will provide a bass line for the corals.

I bought one Kessil AP700. I don't know if this is true but I believe that a bulk Reef Supply video reviewed it highly because they said that almost no matter how I tune it for cosmetic reasons; the corals will get fed what they need.
After doing it for two 250 watt metal halides, I plan to use a microcontroller to move the Kessil across the tank to simulate the sun's motion. I feel that this will make for more interesting viewing and hopefully more even growth while saving a buck or two.

I have incorporated four dimmable 48 inch T5's that do not have reflectors. BRS also suggested that adding them, rounds out the spectrum, increasing the odds of having healthy coral growth. They also take a bit of the edge off of the shimmering which can sometimes be too much.

Now "¦ I have two pairs of cheap 50 watt COB lamps from China, reportedly sourced from Sweden. One pair is 455nm and the other two are 420nm. They were left over from a resent project. I will have a good dimmable driver for them but will not use lensing or reflectors. I plan on putting them low, as close to the top front of the tank as I can so that a different angle from these lights will throw shadows that are slightly different than all the rest. Hopefully, that will add interest to the look, perhaps not.

As much as I try, I can't find very many answers to a few questions. Will an additional 200 watts (total) of blue and violet light be too much for the coral? I can find very little information on violet light burning corals and almost nothing on blue light maximums.

Some knowledgeable people say yes and some say no but it looks like this light can burn corals so I will use dimmable drivers on them as well but has anyone burn coral or made them very unhappy with just blue and/of violet light? Should I just throw these LED's away?

Can you help me learn more about the effect of those slices of the spectrum? Do you have any comments on any part on the project?

 

[Ron Reefman]

It sounds like you have spent a lot of money on fixtures and mounting systems. You have a wide variety of different kinds of light. Nobody can honestly tell you if you have enough or too much. You would do well to get some kind of PAR meter, even a cheap one so you can offer PAR numbers that mean something rather than watts which is like saying 'how fast is my car? It gets 10 miles to the gallon. (watts)' When what you want to know is MPH. (PAR)

BTW, what are the other dimensions of your tank? Most 180g tanks are 6'x2'x2'. If yours is 6'x2'x31" it's probably a 220g or 225g.

 

[herring_fish]

I am glad that you answered me back. I found it very difficult to resist PM'ing you with this. Thank you.

I wish that I had gon for a 225. The dimensions of my tank are 6 feet long, 31 inches deep and 18 inches front to back.

The first post was a little long already so I didn't talk about my plan to get a Seneye PAR meter rather than one from Apex. I think that better ones are out of my range.

I like this one because it is supposed to be better at reading more than just PAR. Blue is what I am unsure of and the reviews point to Seneye in that area. I can also use the other features on my little garage phytoplankton farm. The vestals are always in a cycling phase so ammonia, remote temp, etc., can provide ongoing value.

Even having a meter, I just didn't have closure on blue and violate. I mentioned that I was able to talk to a manufacturer that thought that there wasn't any limit on that end of the spectrum. This just didn't sound right to me but not enough people can say much other than what they feel in their gut.

Some say PAR is PAR. I get the feeling that others would say that blue par should be evaluated at 75, 50, 25 percent or even not at all.

 

[Ron Reefman]

Feel free to PM me if you want, lots of others do!

Your post said,"I mentioned that I was able to talk to a manufacturer that thought that there wasn’t any limit on that end of the spectrum. This just didn’t sound right to me..."

I don't understand what is meant by a limit?

PAR is PAR, light photons are light photons... more or less. There are other points to consider.

Like PAR vs PUR. PAR is fairly straight forward and easy to measure to a fair degree of accuracy. PUR is extremely important, but what is the spectrum that is useful to any specific coral? Is that the same PUR for this other coral? And how do we measure the specific spectrums? You can't with the equipment at our disposal. You can't do anything but generalize and say most corals use mostly blue spectrum.

IMHO, violet is more about color pigments and fluorescence than about photosynthesis. But I readily admit that's just my opinion based on what I have read.

The other consideration is the PAR meter itself. I still use my old Apogee QMSS-E which really has issues reading deep blue and violet. Yet I can run an led fixture that has an equal number of white and blue leds on 2 separate channels and measure them with my meter. The white channel will typically have 10% to 20% more PAR than the blue channel. That's because of the deficiency in my PAR meter and not that blue light has less PAR.

I hope that helps? If not, ask more questions.:thumbsup:

 

[herring_fish]

I guess when I say “Limit” I mean, the point at which my new corals (when I buy them) will bleach or otherwise be stressed because of too much light.

It sounds like I should just treat blue light as any other part of the spectrum. Unfortunately, you are saying that I don’t have a “Get Out of Jail Free Card” when it comes to blue light. It’s funny that we can even have this discussion thanks to the advent of LED’s.

I don’t know if I should even bother with taking these blue and violet chips out of the drawer and DIY’ing them into service. The kessil + T5 combo should give me the cosmetic appeal that is most highly touted by the marketeers. Then I should be able to tune the look of the tank to my personal tastes.

Now let’s move on to the subject of motorizing the Kessil to move across that tank. Apart from the technical side of things, managing this kind of scheme could be pretty interesting. It might be a little tricky to manage PAR when the fixture moves. I have heard of it being done in coral propagation but there isn’t much that I can find on results and/or pitfalls.

Do you have any thoughts …directly related or not?

 

[herring_fish]

This is what I did in the past.

I heard about LED light being too unidirectional in some cases. With the rapped advances in motion control someone could move the light array for very little work and money. I built a unit back in the 90's like this one with two 250 watt metal halides, facing away from each other, inside of a 6 inch square polycarbonate tube with a fan at one end which prevented it from ever melting down.

Now, you can buy low tech units right off the shelf. Think hydroponics. You could build a sweet little mini-controller based unit like this one that I build for feeding plankton. It could be pretty inexpensive.

 

[herring_fish]

Being a designer, it is easier for me to think up things than to implement them but I have laid out louvers to keep stray light off of the glass walls of the tank.

I also thought about cutting a couple of Fresnel lenses in order to redirect the wide angle of the LED fixture. This wide angle is featured as part of why the AP700 is less likely to burn corals but a large part of the light would be lost in my tall narrow tank. By cutting two of them slightly off center (green line), I hope to get the center of each lens (yellow circle) directly under an emitter. Then I could cut away the middle in the other direction (red lines), so that light will go, uninterrupted to the bottom of the tank. On the other hand, the wasted light would be redirected straight down and away from the glass. This would require a little tuning but I did some testing with other LED's and it seemed to work the way that I would expect.

I was working on the packaging but ran across another BRS video. It measured the PAR levels under different conditions. One thing that stood out for me was that when measuring a large wide array of T5's. It found that a large amount of the light did reflect off of the glass, back into the tank to increase PAR down low. It made me thing that this might be part of why so many people have success with them. Perhaps the already defuse light is further improved by cross reflected light from the glass and bank shot, up lighting from the sand.

I would like to cut down on cleaning the glass but maybe all this light restraint is a bad idea.

 

[Ron Reefman]

I think it's a really interesting project if you have the time. It just seems like one heck of a lot of work and expense for very little improvement in coral health or growth. But that's just my opinion. I guess I'd also worry to some degree about rust on the metal parts.

 

[herring_fish]

Yes, the amount of DIY work is a concern because reefing is my second hobby and I'm not sure how much horsepower that I can apply to all of this. I do this more for mental entertainment. I find tinkering around with equipment is fun. Sometimes I love the results and sometimes I have to go back to the drawing board.

Primarily, I use plastic for this kind of stuff. You might be surprised how many things can be sourced in plastic. Where I can't, I use aluminum and stainless steel hardware.

As for the expense, I could have purchased a different brand which might have been less expensive. Going forward with that company, for my tank, two units are suggested. Cutting that in half would be a great think from that stand point. If I motorize the LED, I can save many hundreds of dollars.
The shielding and redirection of light is just a project that grows out of having to clean the glass so many days per week "¦week after week after week "¦for decades. If I could put some time in now and it worked, it could save me so much time.

Again, this is mostly just for fun. "¦but my concern is whether all this would actually be detrimental to the corals? You have given good feedback that may have saved me from burning a lot of corals. There just aren't that many experience people that will step up and give advice based on what they have done. Aside from the expense and work, what do you think the LED movement and shielding will do for or to the corals?

 

[Ron Reefman]

IMHO, and that's all it is, opinion, I don't see any of what you are considering as being 'detrimental' to the corals.

On the other hand, I only see it as very marginally improving the system. Maybe you get a better light overall, not a bad thing but then not a big deal either. You also might get a bit better growth pattern as leds do tend to be very top down with shadows that don't help the underside of bigger, branching corals. But then just adding a couple of t5 fluorescent bulbs could do the same thing and be far less complicated.

 

[herring_fish]

Thank's a lot for the help.