Open top reef, or covered

[SmartWrasse]

Planned reef is LS, LR etc, in 75g AGA with MH 250watt X2 6500K and X2 VHO actinic lighting in 10 to 12 inch tall canopy with at least 2 fans.
So the MH lights may be a bit warm. Can I not cover with tempered or whatever glass if I chose?
Thanks, Mike

[Nagel]

my 75 has the same setup, and no glass cover. be prepared for evaporation ( I evaporate 2g or so per day).

I have a PFO dual 250w ballast pushing 2 x 250 w iwasakis, and a PFO dual VHO ballast with 2 x 36" (95 w) VHO 7100 k bulbs. I like the look.

[Hawkdl2]

You will very likely find that you need the evaporative cooling effect of an open tank to deal with the heat from your lamps. If you have any fish at all you will want to put some egg crate or screening on top of the take to keep jumpers in. Use the 2' x 4' plastic egg crate panels for light fixtures at HD or similar - about $8.00 per sheet (find a broken one and ask for a 50% discount).

[SmartWrasse]

The heat issue will be something to see. This will be in the basement where it is often mid to upper 60's in winter (until I hit the gas logs) and rarely above 70 in summer.
I am thinking about trying a glass top under the canopy before livestock to see what happens.
Thanks

[wickerj]

I also have my tank in my finished basement where it stays pretty cool. I have a 58 gal and run a 400 watt 20K bulb. I have to keep my top open to keep the temp at an acceptable level. I also have a 4" fan in my canopy blowing across the top of the water. Don't put a cover of any kind on your tank. You'll be cleaning it all the time and you won't get any evaporative cooling.
Jeff.

[neuroracer]

If you do decide to put glasstops on, for whatever reason, don't buy the all-glass glasstops, because they cost an arm and a leg, like 45 bucks apiece here in NC... go to your local glass company or glass cutter, they'll cut exactly the type you want, the thickness and charge like 3 bucks. Big difference!

neuroracer

[SmartWrasse]

So you get a bit of greenhouse effect from the glass over the top and add on lack of evaporation resulting in too much heat.:rolleyes:

[Hawkdl2]

I just can't see any good reason to put a cover on the tank. Condensation, salt creep and algae will all reduce light transmission and cut down on available light to the tank. As others have said, even in a cool basement, heat entrapment could very well be a problem. Unless your having trouble heating the tank, why use a closed top?