Glass top under canopy?

[SteveM]

I'm setting up a new 29G, and for the first time I have a wood canopy to go on top. I have a coralife PC fixture, which will be up about 2" from the top of the tank on its legs. The coralife instructions are quite adamant that there be glass separating the light fixture from the water, but since it has an acrylic lens cover I'm wondering if this is really necessary. Putting the glass top in under the canopy makes things quite a bit less convenient as far as access to the tank, but I guess if its necessary its necessary.

Any opinions?

 

[flipz]

I can't speak specifically for your fixture because i don't have anything that advanced (so hopefully someone else will help out) but i can tell you that in my personal opinion, if all the components of the hood aren't protected from the water, they need to be.

one of my tanks is a small little 10 gallon and it had a hood with a light that doesn't have a cover between them and the water. let me tell you that these bulbs burn out on a very regular basis, and it also became very rusted in there, and ive had to replace the switch twice from it rusting out. i finally cleaned it out real good, and sealed it up just using some window cover (basically the same thing has syran wrap but thicker) and double sided tape, and i haven't had any problems since.

so basically what im saying is if any of the hoods components would be exposed to water... don't try it! good luck

-brent

 

[slowboattochina]

Glass tops also help so that nothing is ever accidently knocked in. Wouldn't want electrocuted fish

 

[Blazeherd2306]

or you can use a thin acrylic top since they're better at letting light through than glass.

 

[jsoong]

Acrylic top will start to melt & sag under light, esp a pc. You can try 1/4" lexan but that is very expensive (like $300 for a 4x8 sheet).

In the DIY forum a year or so ago, someone solved the access problem by making a sliding top. You slide the front half of the glass back to access the tank, without having to remove the canopy.

 

[Blazeherd2306]

a plexiglass cover thats about 1/4 of an inch thick wouldn't melt would it?

 

[megos1]

I know someone who just has the light without the glass piece and there aren't any problems.

 

[jsoong]

a plexiglass cover thats about 1/4 of an inch thick wouldn't melt would it?

I have no personal experience but others have reported that Plain old acrylic - including plexiglass, even at 1/4" will sag over time under lights.

I suppose it all has to do with how hot your light get, how close it is to the plexi & how much ventilation around the top, etc.

Those "acrylic" covers in the halogen lights are actually lexan - which is more heat resistent.

 

[SteveM]

Thanks for all the suggestions. I went and priced acrylic at HD, and it looks like I'd need to spend about $30 for a 1/4" sheet that would fit my tank. The only lexan they had was thinner, 3/32" I think, and it was definitely not thick enough to hold its own weight. With the thought that it might just end up melting into my tank I'm leaning against this approach for the moment.

On their website I found an all-glass versa-top that is designed for their twin-tube light fixtures. Instead of the seam in the middle, it has a larger glass in the back and a thin strip in the front. I think I'm going to have my lfs order one and give that a try. Hopefully it moves the seam far enough forward that it is not blocking the light and I can open it without interference. Has anyone actually seen one of these?

 

[malkore]

If it's in a canopy, you'll have more moisture buildup inside since the air doesn't circulate very well. It could condense and short out.

SteveM - yes, those are how they make the glass tops for wider tanks, the 18" wide instead of 12". The back glass is about double width of front piece, and I still use the plastic trim piece along the back (to help reduce evaporation).

 

[jibboo]

I have the same situation ... i have a 55g and have a 48" Current-USA PC light on top. I originally left my glass canopies on ... but it got frustrating since they don't fit perfectly on my tank, always hit the light when opening them and they also get all these water spots which (I think) prevent a certain amount of light from shining in. So, with that said, I've had my glass canopy off of my tank for at least 2 months now ... basically my light just sits over top of the water (yes my light has a plastic slot covering the bulbs ... so there is something between the PC bulb and the water)

I think the only things to be concerned about are if your light would ever fall or drop into the tank (mine seemed pretty sturdy, so I tried it and haven't messed with it since) ... and if you have any fish that jump or attemp to escape. And ... evaporation is an issue (especially in the winter/dry-air months). I typically had to top off my tank once in between my weekly water changes. I'd lose between 1-2 inches of water each week ... although it appears to be slowing now.

I'm no expert, but that has been my experience

 

[SteveM]

I went ahead and had my lfs order the glass top with the wide back/skinny front. I never could find measurements for the front/back split, but hopefully it is moved far enough forward to get out from under my light fixture. I should get it on Thursday - I'll let you know how it works for me.

It looks like they make them for 55G also - it would probably help your problem with opening the tops. I know what you mean about the spots though - I clean the tops on my 75G every week or two trying to let in as much light as I can into the tank.