Problems with glass tops anyone?

[Kats]

about 1 week after we had our 46g running (with a glass top) we saw that the top had cracked and returned it.  I remember posting posting here and most of you agreed that we had just been unlucky and that it rarely happened...

Well, it just happened again...  Is anyone else having problems with glass tops?  Ours is a bow front so BA always have to special order it... a pain    We have the Hagen Glow T5 (2x39w) setup.

I'm curious to see if anyone else is having similar problems. 

Here is a picture of this crack, the other one happened in the same side, same spot (more or less)

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[woodendude]

Cracked in the same place, same tank, it sounds as though your lighting is  possibly creating a pressure point causing the fracture. Have you checked the bottom of the unit for any unusal bumps or uneven spots, etc... also check the inside lip of the tank frame for uneven surface.

[fishycanuck]

I never had a crack, but also could never get the sliding parts to work. In the end, I had my husband epoxy a handle on it and I just lift it off. Fortunately it's my quarantine tank so I rarely use it - it's a drag. 

[kennyman]

The only top I have ever seen crack happened because there was heat being conducted from the light housing directly onto the glass panel. Does your light hood have plastic feet to elevate the unit and insulate whatever it is resting on?

Also is the glass touching the body of that AC filter and the lip of the frame at the front? Does it have room to expand every so slightly when the light comes on?

[dan2x38]

Also is the glass touching the body of that AC filter and the lip of the frame at the front? Does it have room to expand every so slightly when the light comes on?

Good thinking Kennyman I would put my money on that bet...

[Adam]

I had my glass top on top of a large pot (so nothing to expand into).  I put the very same hagen 2x39W on top of it, with no airspace between the glass and the fixture.  A couple days later and the glass had cracked exactly where the fixture had been.  I'm going to vote it's the heat with nowhere to escape, and not expansion of the glass into a solid surface.

[dan2x38]

Heat alone should not crack the glass. If cold or cool water splashed on it when it was very hot, yes...

[charlie]

Kats , can you post a picture with the light fixture in place( the way it would normally be mounted), i don`t think it`s the heat from the fixture , i run the exact same fixture on a glass top & no issues & i don`t think you have a wood canopy ( cap ) on the tank to trap heat.

If it`s not covered under warranty, check into getting a piece cut locally @ Rossen glass in Kanata.
http://www.rossenglass.com/glass/index.php
Regards

[Kats]

Hi all,

Jim here. I'm Kat's hubby...

Good thinking Kennyman I would put my money on that bet...

That's a good idea, but it's a no go... There's at least an eighth of an inch clearance all around for expansion.

The light is a Hagen GLO and it sits on a wire frame that is supported by the edges of the tank, there's about a quarter inch clearance between the bottom of the lighting fixture and the top of the glass top, and the T5s themselves are recessed further from the glass...

I'm pretty frustrated with these tops.  This simply shouldn't happen as far as I can see... I suspect it's merely the result of cheap glass - I can't imagine quality tempered glass breaking like this! My car windows get hotter on a hot summer day than this top gets with the lights on for eight hours!! I'm sure it has to do with the heating and cooling under the lights, but give me a break - it's an aquarium top, and the fixture never gets so hot you can't rest your hand on it; we're not talking extremes in temperature here.

I called BA's and they're going to talk it over and get back to me... I'm hoping we can source a higher quality glass top from them... I'm also planning to lift the fixture a bit.

[Kats]

Kats , can you post a picture with the light fixture in place( the way it would normally be mounted), i don`t think it`s the heat from the fixture , i run the exact same fixture on a glass top & no issues & i don`t think you have a wood canopy ( cap ) on the tank to trap heat.

If it`s not covered under warranty, check into getting a piece cut locally @ Rossen glass in Kanata.
http://www.rossenglass.com/glass/index.php
Regards

Hey Charlie!  Here are a few pics...  the one where you see the filter is kind of misleading as you might think that the water is touching the glass but it does not, there is almost 1 inch between the filter/water and the glass.



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[kennyman]

Yea 2 of these things breaking in a row would get under my skin too. I have never owned the Hagen light unit, but I do have a pair of Coralife Power compact units. "Basically T5's that go in a loop" and they have legs on them that put the acrylic shield 2" above a glass top.

[charlie]

Hey Charlie!  Here are a few pics...  the one where you see the filter is kind of misleading as you might think that the water is touching the glass but it does not, there is almost 1 inch between the filter/water and the glass.

After looking @ the pictures , i `m now thinking the heat might be a factor, here is why , your fixture is sitting lower than mine & there is not much air going through there, i did some test on mine & even though mine is sitting higher ( as the pic show) i`m still reading about 104 degrees F between the fixture & top.??

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[Julie]

Has to be heat, I have the same glass tops on my tank under metal halide and they don't break.
My fixture is elevated on legs.

[dan2x38]

Well my mind is changed once I saw the pics. That is almost touching the glass. I now believe it is the heat... Oh yeah Adam sorry you were right... 

[Adam]

 

Mine was touching the glass, so it's a very good indicator of too much heat.  I'm running it on some glass and it is about 1/2" elevated and it is fine.