Light Intensity Variations - some thoughts - Page 8 - Lighting

zer0zax · 06-12-2008, 05:11 PM

Geese Hoppy, you might have just invented the next trend! As you guys have stated, the only problem with aluminum foil is the oxidization that can occur. I am wondering how long it would last with all of the humidity from an aquarium... probably not long at all if you run open-top.

Oh well, I am already trendy because I wear a tinfoil hat.

hoppycalif · 06-12-2008, 08:15 PM

Quote:

Originally Posted by treefish

I obviously don't browse these forums often enough because I just discovered this thread today.

Very interesting stuff hoppy.

I admittedly haven't read it all yet. Hopefully I will have some time tonight to thoroughly investigate the data here.

I must say, I'm quite disappointed with your results from the mylar tests; especially considering I am 99.9% certain the mylar you used is from my stock. If you want, I can find the manufacturer information for it. Perhaps conclusions will be different for other mylar types, brands, thickness, etc.

Aluminum foil might be a better choice for your solar cooker as well.

I am also now wondering if the mylar is the reason behind my problems being discussed on another thread. I'm using mylar only as a reflector on 4x24 T5HO. My actual wattage is about 3.3wpg. I assumed I could call it 3wpg safely. Maybe I should have gone with plants that are less light demanding than what I currently have. Certain plants are now dying. This might just be the reason why.

Yes, my mylar is the piece you sent me. It works great for my solar cooker, but now I have to believe that ordinary aluminum foil would work better there too. (tonight we had excellent split pea soup cooked with that solar cooker!)

In my case I was working with a light fixture, the one for the 10 gallon tank, that is very marginal at best, so the loss from the reflector was significant. I don't know if you are that close to having inadequate light, but I doubt it. 3 watts per gallon allows you to lose some of it without a problem.

I'm almost sure the mylar is inferior at doing what we need, which is to redirect the highest percentage of the light from the back side of the bulbs towards the water. It is great at letting us see a good image of the back of the bulbs, but not so great at capturing all of the light energy involved. The aluminum foil is bad at showing us a good image of the backs of the bulbs, but who cares? It does reflect more energy, if somewhat chaotically, which is what we really need. The white paint does the same, but totally chaotically.

zer0zax · 06-17-2008, 07:59 AM

Hoppy, do you still have the PAR meter? I am really curious about dual bulb reflectors and the amount of light lost. If you have some T8s laying around it would be interesting to see 2 bulbs running in one reflector versus one bulb running in the same reflector (other bulb completely removed).

If anyone has any ideas or charts on this that would be awesome! (Sorry for hijacking thread!)

hoppycalif · 06-17-2008, 08:31 AM

Quote:

Originally Posted by zer0zax

Hoppy, do you still have the PAR meter? I am really curious about dual bulb reflectors and the amount of light lost. If you have some T8s laying around it would be interesting to see 2 bulbs running in one reflector versus one bulb running in the same reflector (other bulb completely removed).

If anyone has any ideas or charts on this that would be awesome! (Sorry for hijacking thread!)

I don't have the PAR meter now. It was borrowed from Tom Barr. I'm sure I could borrow it again if I needed to. But, I don't have any T8 fixtures laying around. As long as you are willing to just test a fixture in the air, and not measure the light in the water, you can use almost any incident light meter for this. You will get comparative numbers for different reflector/bulb configurations, but no numbers that can be used to compare to readings other people get. I think the comparative readings are just about as good anyway.

newbie314 · 06-18-2008, 05:54 PM

So you've done the whole solar cooker thing too.
What did you make out of it?
Funny I was thinking the same thing about cookers that aluminum foil should work better than mylar.

I wonder how my mylar with the white backing would work?
Can buy it locally in sac. here.

Quote:

Originally Posted by hoppycalif

Yes, my mylar is the piece you sent me. It works great for my solar cooker, but now I have to believe that ordinary aluminum foil would work better there too. (tonight we had excellent split pea soup cooked with that solar cooker!)

In my case I was working with a light fixture, the one for the 10 gallon tank, that is very marginal at best, so the loss from the reflector was significant. I don't know if you are that close to having inadequate light, but I doubt it. 3 watts per gallon allows you to lose some of it without a problem.

I'm almost sure the mylar is inferior at doing what we need, which is to redirect the highest percentage of the light from the back side of the bulbs towards the water. It is great at letting us see a good image of the back of the bulbs, but not so great at capturing all of the light energy involved. The aluminum foil is bad at showing us a good image of the backs of the bulbs, but who cares? It does reflect more energy, if somewhat chaotically, which is what we really need. The white paint does the same, but totally chaotically.