Eggcrate on top of tank, effect on lighting

[chevegan]

I want to be rid of the glass on top of my tank to let in more light. Plus I'm Oh so tired of keeping them clean. Eggcrate is he best way to do that. I just wanted input as to whether or not it has any effect on par ratings. There is also the mirror finished eggcrate which in an office will actually increase light substantially. Any thoughts?

[aninjaatemyshoe]

First of all, eggcrate is only appropriate with fluorescent (ie long-tube) lighting. It will not work well if you are using metal halide. I've used eggcrating with a t-5 fixture before. While I did not have a way to measure the effect on par, I would say that the light levels did not go down in the tank appreciably. I would guess that the effect on PAR is minimal. When comparing using glass tops with using eggcrating, I would definitely say that more light gets in with the eggcrating (especially when you factor in how quickly the glass gets dirty).

Stay away from the mirror finished eggcrate. The mirror-finish paint is likely to flake off into your tank. Who knows what it will do then.

[Runfrumu]

Eggcrate blocked a ton of light with my 150 HQI's. Try making the one with the screen door kit and hardware mesh. Theres a DIY thread somewhere. I made one last week and it blocks no light at all and will keep things from jumping out of your tank.

[chevegan]

I should have mentioned, I have a 6xT5 light setup.

[reefergeorge]

I don't know for par, but with the egg crate on my tank it lights up the entire room. When you take it off the room is much darker. I have the nova 4x54 t5.

[nikon187]

+1 for the bird net window screen top. Its great and doesn't let light spill into the entire room, doesn't block any light and keeps fish in if small enough netting is used

[jtma508]

I use eggcrate on the top of my tank and am only using PC lights at the moment. I don't notice any appeciable lessening of light into the tank.

[chevegan]

i placed it on last night. I see a very slight difference in the light to the very front and back of the tank. But nothing that will seem to matter. Especially considering the fact that before it was trying to penetrate through glass that gets stained consistently.

[chadfarmer]

flip it over and see if you like it better

[Alastair]

I used black koi filter grid as a cover on my tank for a while.. I used some thin clear acrylic whilst I had T5s but when I switch to the halides this couldn't take the heat.

There were two effects.

1. The overall illumination in the tank was vissibly reduced.
2. The shadows were dramatically increased, the ends of the tank received almost no light. It was very dramatic, but not beneficial for coral husbandary.

I switched to a glass top as soon as I could get it cut. To save hassle I had feeding holes drilled in the glass. To reduce salt creep I mounted the glass on dozens of rubber bumpers (the 2-3mm rubber feet sold for computer cases) to leave an air gap. Once every couple of weeks I rinse the glass in the shower.

This is the tank with the grid fitted.

http://i145.photobucket.com/albums/r222/SaltGeorge/Aquaria/PICT2174crw.jpg

As a halide it's a point light source, with T5 tubes ther shaddow effect will be less.

This is now quite an old pictures and my tank (http://www.marinefish-uk.co.uk/forums/index.php?showtopic=16931&st=125&start=125) has moved on quite a bit since.