[MichaelMcG]

I strongly suggest you check this out. I believe Hoppy has par values for this in his lighting thread. Very good chrome reflectors.

http://www.homedepot.com/p/Lithonia...escent-Shop-Light-Fixture-1241DP-RE/202192989

 

[sowNreap]

If you're going to be using pressurized CO2, & since you want high light, you might want to try two of the 3 bulb version of that Diamond Plate fixture: http://www.homedepot.com/p/Lithonia...te-Fluorescent-Shop-Light-1243DP-RE/203300803 .. online shows it being black outside but I was just in my store a couple days ago & the display was chrome. Might have had black too but didn't check. The 3 bulb version is basically the 2 bulb one with a 3rd bulb added into the center that hangs a bit lower than the other bulbs.

My guess is two of the 2 bulb Diamond plate fixtures will give you closer to medium light except in the center where the light might overlap giving you a bit higher PAR. YMMV.

I have 1 single bulb t8 strip & one dual T8 Diamond Plate fixture (total of 3 bulbs) hanging about 24" & 27" above substrate on my 75 gal tank (only 18" deep) & I figured I'm low-medium but my setup is kind of weird. If my Diamond plate fixture was hanging lower the light would be too high on the back side of the tank without getting algae or using pressurized CO2.

If you find two of the 3-bulb fixtures are too much light check to see if you can disable one bulb & the fixture still operate correctly. Or you can use window screen or hang the fixture higher. Even the clear tube bulb protectors can cut the light just a bit .. not a lot though.

Nice thing about Home Depot, it's easy to return stuff.

 

[AlecFish]

If you're going to be using pressurized CO2, & since you want high light, you might want to try two of the 3 bulb version of that Diamond Plate fixture: http://www.homedepot.com/p/Lithonia...te-Fluorescent-Shop-Light-1243DP-RE/203300803 .. online shows it being black outside but I was just in my store a couple days ago & the display was chrome. Might have had black too but didn't check. The 3 bulb version is basically the 2 bulb one with a 3rd bulb added into the center that hangs a bit lower than the other bulbs.

My guess is two of the 2 bulb Diamond plate fixtures will give you closer to medium light except in the center where the light might overlap giving you a bit higher PAR. YMMV.

I have 1 single bulb t8 strip & one dual T8 Diamond Plate fixture (total of 3 bulbs) hanging about 24" & 27" above substrate on my 75 gal tank (only 18" deep) & I figured I'm low-medium but my setup is kind of weird. If my Diamond plate fixture was hanging lower the light would be too high on the back side of the tank without getting algae or using pressurized CO2.

If you find two of the 3-bulb fixtures are too much light check to see if you can disable one bulb & the fixture still operate correctly. Or you can use window screen or hang the fixture higher. Even the clear tube bulb protectors can cut the light just a bit .. not a lot though.

Nice thing about Home Depot, it's easy to return stuff.

Hope I'm not butting in or anything but SowNreap, what was your placement of the two fixtures over your 75g. I have a dual T8 diamond plate like you but I feel like I'm not getting enough light spread to the very front and the very back. It's getting to the extent where I can't see my rainbows full colors. The fixture is sitting right on top of the glass. I'm curious to see how you do it, because it's something I might want to try out.

 

[sowNreap]

Like I said I have a very weird setup & almost hate to describe it. :icon_redf It's not a show tank that's for sure but looks ok to me & suits my purpose on my limited budget.

My single bulb strip which has pretty good reflector is located in front half of the tank but it's tilted slightly toward the back. The Diamond plate fixture is on the back half of the tank & it's also tilted toward back so the front bulb is maybe 2" lower than the back bulb and the whole fixture hangs about 2" higher than the front fixture. This helps to light my HOB plants. It's almost like using a single fixture that has 2 bulbs 8" apart or two single bulb fixtures 8" apart. That 3rd bulb doesn't put that much light into the tank.

Since I feel the need to explain this weird setup :icon_smil here it is. One, I already had holes in the ceiling for 2 fixtures in those spots & didn't really want more holes in the ceiling. Secondly, and really the main reason, the spillover light from the Diamond plate hanging above the tank blinded me just walking around the room. So I came up with this arrangement since I already had both fixtures.

If I remember correctly, during testing it seemed I got the most even light spread for the PAR I wanted at around 24"-25" from substrate to bulbs. Meaning the "PAR" varied less from the center versus the front/back. For example, at 24" I got about 39 PAR in center while the front/back was about 33. Lowering the fixture to 21-22" produced more light in center like maybe 45-50 PAR while at the front/back was still only 30-35.

This post might help visualize it better: http://www.plantedtank.net/forums/showpost.php?p=2024596&postcount=37. You can read the whole thread if you want to see how I tested & problems I had, etc. Basically used a Lux meter & hung the fixture in open air. Small measurement errors & it appears the light reflecting off my back kitchen wall caused the numbers to vary. I did the best I could with what I had which gave me a general idea at least of the light level & spread at various heights.

Edit: I almost bought a 2nd dual bulb diamond plate & was going to try running one bulb from each fixture in order to get better spread but have it hang lower or even right on top of tank. I didn't really want my lights sitting on tank though. And once I measured my single strip & looked at the figures/heights/spread, I figured I could work with it better since it blocked off the spillover light.

 

[AlecFish]

Whoa! I never realized that a work light would have such a high PAR rating. I still don't get how to get more light spread... I tried to raise it off the tank using a couple blocks of wood but I keep getting blinded when I walk by the tank. Do you think changing the spectrum of the bulb would have any effect on the light spread?

 

[sowNreap]

Yep that light will blind you for sure! I don't think you can get more spread using a different spectrum but a pinkish bulb (such as the zoomed flora sun) might not be as blindingly white as daylight 6500k bulb.

I tried using a plastic tube protector with a thin strip of window screen to block the light just on the side facing out which helped some... Just didn't like it.

If you can figure out how to extend the reflector so it looks decent that would help light spillover.

Sent from my HTC One V using Tapatalk

 

[zigis]

I have three icecap 430 ballast that can run 12 two ft bulbs or 9 four ft bulbs
or 6 five ft bulbs. I have reflectors that are polished aluminum. I'm running two 165 watt led panels now and was thinking the large group of T8 would be higher light.