[hoppycalif]

I have a 10 gallon tank I plan to experiment with, first with a non-CO2 approach. But, the light is a single tube 17 watt fluorescent bulb. This could be enough, but it might not be, and the bulb is buried in a narrow white plastic slot - no reflector to speak of. So, as a fun project I am modifying it to use two spiral CFL bulbs, first two 15 watt bulbs, 6500 K. And, I am putting in a DIY reflector. First, the Perfecto Hood:

and its removable light fixture:

Notice that the light uses a starter and a magnetic ballast.

I removed the light parts, which involves unscrewing 4 screws and cutting the wires:

Then to the hardware store for parts: the sockets, ceramic ones to best resist any heat, a package of threaded nipples and matching nuts, and the bulbs:

A lot of studying of the housing, how it was shaped and how the bulbs would fit inside, and a lot of sketches, and I decided I needed a 6 inch by 14 inch piece of aluminum sheet, so I went back to the hardware store for that, then marked it for cutting and used tin snips to cut it:

The first photo shows the surface of the aluminum sheet before I started trying to make a mirror finish on it. The second, the opposite side, shows it after using 220 grit sandpaper, followed by fine grit coated cleaning pads, followed by #0000 steel wool equivalent polishing pads, rubbing with toothpaste, and using commercial metal polish on it. Still not close to being a mirror.

 

[hoppycalif]

A trip to Home Depot's tool department led me to buy a cheap hand drill model polishing pad set, with polishing compounds.

After using that to polish the flat metal surfaces as best I could, I bent the mirrors to a crude "parabolic" shape, re-polished the surfaces again, washed it with dish soap and water, and sprayed it with clear spray can lacquer.

The lacquer is now drying, so I started assembling the light.

And, this is where I stand with the project for now. After another couple of hours for the lacquer to dry well I will continue the assembly and continue the reporting.

 

[hoppycalif]

Here is the reflector installed, with the bulbs installed to check how much added area of the bulbs can get light into the tank.

You can see from the reflections of the bulbs that considerable more light can be collected this way, but the reflections are far from perfect - maybe a third of the light actually gets reflected. So, the question I need an answer for is: should I use it this way, or add aluminized mylar to the surfaces, and why? I was able to get some very good quality mylar from nokturnalkid and jazzlvr123 that I can use, nice thick stuff, but I'm concerned that so many seem to have found that mylar isn't able to survive well in this application for over a year. So, what should I do?

 

[hoppycalif]

Those are the energy saver bulbs that go into standard incandescent bulb sockets, with no starter or ballast needed. Both are in the bases of the bulbs. So far I haven't done the electrical connecting, and I don't think I have an wirenuts, so I won't do that until tomorrow. But, first I need to decide about the mylar.

 

[hoppycalif]

The light fixture housing has moulded in "towers" where the screws held the original guts in place. Those have to either be used to hold the reflector, or cut off leaving a problem trying to hold the reflector in place. I left them there and bent a zig zag into the reflector to get the reflecting part as far from the bulb centerline as I could. I couldn't easily do that with those pre-made MIRO reflectors. And, my goal was minimum cost or I would just have purchased a 2 X 13 watt AH Supply kit. Besides it is more fun this way.

 

[hoppycalif]

So, after thinking about this for a day, and thinking about those beautiful mylar reflector sheets, I went ahead and installed the mylar. I used 3M Super 77 spray adhesive, sprayed on the aluminum reflector surfaces, then just pressed on the mylar. The easiest part of this modification. Here is what it looks like now with the lights on. (Note that one bulb is defective.)

Looking at the light from the ends, to see how much gets reflected back to the ends of the tank:

And looking to see how much gets reflected towards the area in between the bulbs.

If this holds up well, and if I can get a bulb that isn't defective for the second socket, this seems like a real winner for increasing the light intensity for a 10 gallon tank. The parts cost about $15, not counting the bulbs, which cost $12.

 

[hoppycalif]

To see the finished hood, lighting up the tank, go to: http://www.aquaticplantcentral.com/...osand-diamond-black-substrate.html#post337735

 

[hoppycalif]

This light does a good job covering the entire substrate with light, probably high light intensity. Because the water is cloudy from dust in the substrate you can see the light pattern looking from the end of the tank:

 

[hoppycalif]

PM sent.

I think 60 watts of T8 on a 30 gallon tank, if you put a reflector behind each bulb shaped to capture most of the light from the back of the bulb and direct it into the tank, will be close to high light intensity. And, 80 would definitely be.

 

[hoppycalif]

the perfecto i picked up at petsmart now uses pc lights with reflectors, 2 13watts to be precise.. strange

If the reflectors are good ones, that lighting should be adequate for most plants. Apparently there are several versions of the Perfecto hood. The one I have was brand new, but I bought it through Craigslist from a lady who had not set up the tank, and decided to get rid of it instead. She may have had it for months if not years.

 

[hoppycalif]

what type of switch did you use and how did you wire your lights

That Perfecto hood had a switch on the back, so I just used it. The wiring is very simple, since the ballasts are in the bulbs. You just connect one white wire and a black wire to each socket, then connect the white wires to the power line white wire, and the black wire to the power line black wire. The power line green wire is the ground, which goes to all metal pieces, from one to another.

 

[hoppycalif]

I'm not at all sure what the current rating is for that switch. My guess is that it would handle 10 amps, which is about the lowest amperage a 110 volt switch is made for. That would be about 1000 watts, or 4-250 watt bulbs. Even 4-25 watt bulbs would only draw about one amp, so it is very likely that the switch will work fine.

 

[hoppycalif]

GE makes 6500K CFL bulbs, which I got at my local Ace Hardware store. I haven't seen those bulbs anywhere else. I now have 20 watt bulbs in that fixture, with the glass insert in the hood removed, so I get more light down to the water, and much less heat trapped.

 

[hoppycalif]

Today I started measuring light intensity from this modified fixture, using a PAR meter borrowed from Tom Barr. It is a very revealing test!

First, I wanted to resolve my doubts bout the effectiveness of the simple reflectors I used. To do this I moved the fixture off the tank and put it on a simple stand so I could measure PAR at various locations and distances from the bulbs. The set up is:

I measured PAR at 11 different locations over the tank footprint area, for 8 different distances from the bulbs. Then I removed the reflectors and measured the PAR at the same locations at 2 different distances from the bulbs. I plotted that data for the location right under the center of the fixture and that looks like:

You can see that I get about twice the light intensity with the reflectors as I do without the reflectors. To me this proves that simple, mylar covered reflectors like this can be extremely effective, especially for those of us with a limited budget for lighting.

 

[hoppycalif]

how are the plants holding up under these lights?

I'm considering modifying my light fixture (for 10gal, holds one 14W/11k tube), but I don't want to take the step to do so if live plants won't survive.

My plants are not doing well. The actual light intensity at the substrate level seems to be too low, but I'm still experimenting to try to figure out if that is the reason. The tank now has glosso and rotalas in it, plus a small crypt.

If I had that bulb over my tank I would try to figure out how to get a mylar covered aluminum reflector in there to try to get more out of the bulb. I suspect that a tubular light like you have may suffer less drop in intensity with depth than I get with the CFL bulbs, so your 14 watts may give more intensity than my two 20 watt bulbs, down at the substrate.

 

[hoppycalif]

That looks great Hoppy! Any chance you can shove some aluminum foil behind the bulb and see how that goes? I've always wondered how much worse they are as reflectors. There is also the lack of consensus on how good diffuse white reflectors are. I can't wait to see the rest of your data with the PAR meter.

If I can think of an easy way to get a white reflector in there without ruining what I now have I will make some measurements with it also. I doubt that I will try the aluminum foil though. I can probably keep the PAR meter for a week or so.

 

[hoppycalif]

i diddn't read the whole thread so it might be stated already but did the mylar not workout?

Under the lighting forum I am reporting my results using Tom's PAR meter. One of my "discoveries" is that mylar looks like the perfect reflector material, but it isn't. Aluminum foil is much better. Glossy white paint is even better than mylar. This jolting discovery is easily explained: the mylar makes a good mirror in that it accurately reflects what light strikes it, but it doesn't reflect as much of that light as aluminum foil reflects. Aluminum foil is useless as a mirror, because it doesn't accurately reflect what light strikes it, but it does reflect much more of that light than does the mylar. Glossy white paint (and maybe matte white) is a good reflector in that it reflects a very high percentage of the incident light, which is what makes it white, but it diffuses all of that reflected light so the reflection isn't at all accurate. I hope that isn't confusing.

 

[hoppycalif]

Would doubling the layer of mylar help increase the efficiency

I don't think doubling it would change a thing. It is the metal surface that does all of the reflecting. Light that penetrates that surface is lost, even if reflected with a second layer. The reflected light from that layer would then be reflected again by the back side of the first layer, so very little would make it through to augment the first layer reflection. Aluminum foil is cheap, easy to buy, and works best. Or, just a sprayed on coat of glossy white paint is even easier to apply. I think I will stick with aluminum foil.

 

[hoppycalif]

I'm not sure white plastic is as good a reflector as white paint. I know in bright sunlight a house painted in pure white paint can make your eyes hurt from the reflection. I doubt that white plastic would do that.

 

[hoppycalif]

Today I looked at this fixture and hood more closely. The original Perfecto hood and fixture has glass between the light and the water, mounted on a lip in the hood. The lip is about .38 inch wide all around the opening for the light to go through. The opening is 3 inches by 18.25 inches, so the lip reduces that opening by about 30% in area. That is acting as an aperture to reduce the light entering the tank. So, I trimmed the lip out with a utility knife.

I did some measuring of the light from the fixtue, using a PAR meter, and charted the results:

The red dashed line is what I should get if I replace the mylar reflector material with plain aluminum foil. And, that would, in total, represent a major improvement in the amount of light this fixture provides at the substrate level.