need advice re open/closed aquarium and lighting

[otrlynn]

I can't decide whether to us a glass cover on my new 58 gallon reef tank, which will be an upgrade from my 29 gallon reef tank. I will not have a sump. I am currently using a glass cover on my 29 and have been maintaining good water parameters incl. alk and pH. I have 2 HOB filters (biowheel removed) that contribute a lot of flow and are open to the air themselves, as well as a HOB skimmer. Also, there is a gap of about 2.5 inches between the back of the glass and the back of the aquarium. Excess heat has not been a problem, though I will be upgrading my lighting, so the new tank may tend to get hotter (will be using T5s). I have seen multiple posts recommending open tanks for air exchange but wonder whether there are people out there successfully running tanks with glass covers/canopies. I need to make a decision because it will affect the lighting set up. Thanks for any advice.

[Sk8r]

I can't feature running a larger tank without evaporation.

One nice compromise is a 9" or more false canopy: it has sides, but no top, and lights can be mounted across it. The back can be cut out for equipment and hoses. This false edge prevents jumping and still allows plenty of evaporation. Mine is a simple laminate shell mounted to a very light stick frame---waterproofed painted pine...corner pieces, and a frame that provides a 'resting' edge for the whole canopy. Easy to build, easy to remove for cleaning or maintenance, no heat buildup.

[mg426]

I am in agreement,open top is the way to go.

[otrlynn]

Can you explain what you mean by a false edge? I think I can otherwise picture what you mean Sk8r.

[Sk8r]

YOur tank has a plastic rim, right?
Lay a piece of one x one pine along each rim. Assemble it with dowels [lasts longer than screws] into a light but sturdy picture-frame-like structure. You might put triangles of wood in the corners to keep it stable.

Now paint and water proof that frame.

Get some light material---laminate, some sort of nice-looking exterior. Have your hardware folk cut it into an approximately four 10" strips that will equal the outside measurements of the 4 sides of your frame [mine, being a bowfront has 3, but never mind. ;)]
Now lay one of the longest pieces on your work table and go measure the width of your tank's plastic rim. Go mark that on your laminate's good side.

NOW, set your frame lengthwise on that mark, leaving most of the laminate's expanse above it, and the width of the frame below. Mark it with a pencil.

Get some masking tape. Tape between those two lines: you're about to drill, and the masking tape prevents chipping. Drill holes for your screws [evenly spaced looks better.]

attach your frame to the laminate.

You will need to screw or glue a triangular piece above in the corners, too, to keep it stable.

You can mask the screws by using a strip of molding fixed to the outside of the laminate. You can mask the corner joints by using a corner-cap type of molding to fit the corners. Same with its top edge---if your weight isn't too high, you can create a second 'picture frame for the top' which will enable it to support quite a heavy light unit resting atop it.

Your 'shell' of a canopy becomes capable of keeping mh lighting the requisite 9" above the water, or just of supporting any other kind of fixture; you can build across it to accommodate your lights, etc. And you can make it match your tank, or just do black, or a combo of the same. If you want to get fancy, use a very light ply, [light! is good, because you'll want to be able to lift this on and off solo, and you don't want it warping under its own weight] and glue on a nice wood veneer that will let it match your furniture. Etc. It's a basic design, but the whole deal is, it's a hollow box that comes down to mask your tank rim, and continues above to raise your lights off the water, while resting on an interior frame that resists moisture and yet is light and strong and NOT metal. ;)

[otrlynn]

Thanks for the description!