eggcrate lessen lighting?

azocean709

Member
I am currently running 4 10,000 k 110wVHO's and 2 80 true actinics...will putting eggcrate over my tank lessen the light? even if the lights are only 6 inches above it?<i put up the eggcrate to keep firefish from jumping out>
 

wax32

Active Member
Some, but not by enough that your corals should mind, unless you were keeping SPS that were just barely getting by...
 

wax32

Active Member
The white works fine, it's actually semi-transparent (it's thin so you can see light through it somewhat. I've never since an actual clear one.
 

bang guy

Moderator
White eggcrate that has a thick side & a thin side will actually increase the amount of flourescent light that enters the water. Thick side up.
 

azocean709

Member
Originally Posted by Bang Guy
White eggcrate that has a thick side & a thin side will actually increase the amount of flourescent light that enters the water. Thick side up.
how does it increase the light? thats weird..lol
 

speg

Active Member
Originally Posted by AzOcean709
how does it increase the light? thats weird..lol
I agree.
 

bang guy

Moderator
Originally Posted by AzOcean709
how does it increase the light? thats weird..lol
Light that strikes the water at an angle will reflect off the surface...wasted. Light going through eggcrate gets reflected straight down so that it penetrates the water surface. A little bit of light is reflected from the squares in the eggcrate but a lot of the light that would be reflected off the water surface is reflected down. The net result is a positive.
This only applies to flourescent light, MH light acts differently since it's a point source.
 

bang guy

Moderator
Originally Posted by HSanchez
so is eggcrate over MH's a bad idea?
I really don't know so I can only guess. With MH reflectors already built to reflect the light at an angle that will penetrate the water surface I don't see how it could do anything but reduce the amount of light entering the water, especially with DE bulbs. In addition is the point heat source that could actually melt the plastic eggcrate material.
 

ssweet1

Member
One main point not mentioned is egg crate is of no concern for firefish. I had 3 jump straight through small eggcrate as if it wasnt even there.- unfortunately
Carrie
 

azocean709

Member
Originally Posted by SSweet1
One main point not mentioned is egg crate is of no concern for firefish. I had 3 jump straight through small eggcrate as if it wasnt even there.- unfortunately
Carrie
that sucks....lol thats the whole reason i bought it, was to keep my firefish from jumping out, which to my suprise they have not tried at all, and for some racks in the frag tank.
 

gregzbobo

Member
not sure how this would work, but perhaps fiberglass windowscreen? That would keep the firefish in, but might reduce light reaching your corals a bit more than you'd like.
 

azocean709

Member
I was told once upon a time that when i go to MH that i need to put some tempered glass over the tank to reduce UV as corals are from 5 to 30 ft down and UV only penetrates the first couple ft of water....How about if i make a top out of 1/4 inch thick plexiglass...do you think this will work?
 

gregzbobo

Member
Originally Posted by AzOcean709
I was told once upon a time that when i go to MH that i need to put some tempered glass over the tank to reduce UV as corals are from 5 to 30 ft down and UV only penetrates the first couple ft of water....How about if i make a top out of 1/4 inch thick plexiglass...do you think this will work?

screw in MH bulbs are already UV shielded, and most DE fixtures have UV shield glass built in.
 

uberlink

Active Member
Originally Posted by Bang Guy
Light that strikes the water at an angle will reflect off the surface...wasted. Light going through eggcrate gets reflected straight down so that it penetrates the water surface. A little bit of light is reflected from the squares in the eggcrate but a lot of the light that would be reflected off the water surface is reflected down. The net result is a positive.
This only applies to flourescent light, MH light acts differently since it's a point source.
Far be it from me to question Bang Guy on pretty much anything remotely related to fish, but this doesn't make sense.
The light that gets past the egg crate because it's going straight down would have hit the water going straight down in the absence of the egg crate. The part of the light that would have bounced off the water because it comes in at an angle gets blocked by the egg crate. But even that light coming in at an angle is not entirely "wasted" because some portion of it actually penetrates the water, even if relatively little compared to rays of light that hit the surface of the water at a 180 degree angle. So it would be right to say that the part of the light that is blocked by the egg crate would otherwise largely bounce off the water, but it's not correct to say that it would be (a) entirely wasted were it not blocked because some of it still penetrates, and (b) that the portion of the light coming in at a 180 degree angle to the water would not otherwise come in at the same 180 degree angle in the absence of the egg crate.
Thus, the egg crate lets through the most efficient rays of light coming in at a 180 degree angle, and blocks the less efficient rays coming in at acute or obtuse angles. But the relative inefficiency of the blocked rays doesn't mean that they're completely ineffective at penetrating the surface of the water.
Bottom line: the egg crate blocks a little bit of the light, most but not all
of which would have bounced off anyway.
 
Top