can I cut the plastic bracing?

[dbates]

hey all,

quick question, I just got 2 175 watt metal halides, and have them mounted in my hood, but the plastic bracing across the top of the tank is blocking the bulbs, and putting a big shadow into the tank.

Since it is not euro bracing or anything that is structural, do you think it would be alright to cut them out to allow for more light exposure?

 

[menard]

Are U crazy ? No NO, dont even think about doing this.

 

[Bryan89]

That plastic bracing IS structural.

 

[dbates]

does the bracing help to pull the two sides together? kinda put less stress on the front and back glass? this is what I was thinking and afraid of...

the way it is now, the bulbs are almost directly above the bracings, do you think there is any chance that the heat from them could melt/warp the plastic?

 

[mhurley]

Yes, the integrity of them can be damaged over time by those lights...Heating and cooling plastic will cause it to lose strength over time.

Have you considered installing a glass brace and then cut that one out? It can be done, I've seen people do it. Just clamp the tank, cut the plastic one out, silicone the proper size of glass in there, let it cure for a few days and remove the clamp (and cross your fingers)

 

[Douglas LEHMAN]

Hello
How large is the aquarium, and what brand.

I modified my 26 g bow front, screwed in a 1/4"x3" piece of acrylic.

 

[dbates]

this would be the best way to do it, but sounds like a huge project, especially since we're talking about a full and running tank...

any ideas anyone?

 

[dbates]

it is a 180 gallon All-Glass

 

[Douglas LEHMAN]

Hello
I'd add a third MH, and space the out over each of the three opening ! That's what I'm gonn'a do...

 

[dbates]

ok, update, i just had the lights running for about an hour, and went back to check on them, and they ARE MELTING the plastic, wet, bubbly, darkened spots,

so this problem just became more serious

 

[Bryan89]

Do what Mike suggested above and replace all of the plastic with siliconed glass. Post a photo of the top of the tank, you 'may' need to drain it and repair, depending on how badly damaged it is.

 

[dbates]

well, it wasnt melted, but like a darkened spot, , i think this brace is still functional,

I am in the process right now of just shifting the light over and changing my mounting inside the hood, I think its the easiest way, it will just favor one side of the tank, then I can balance the other side out with my pc fixture...

yea?

 

[mbunaman]

You might want to replace it with glass. It seems like the plastic is getting structurally weak by having dark hot spots on it. Post a pic of the brace so we can help you better. Dont ignore this bigger problems down the road is not what you want.

 

[dbates]

alright, I changed the mounting on the inside, I had wood crossbars inside the hood, so that the 2 light fixtures could just rest across them, and I had to add in 2 more and move one of them

the lights are not positioned above the bracing anymore, so I think it should be good, I'll be able to tell within a few hours...

heres a pic, it is minimal, looks bad, but the brace is still very strong

 

[Dberg79]

Well i wouldnt remove the whole top plastic brace since sometimes the top edges are not finished and smooth. What you should do is what mike suggested. Get a large clamp that can reach across front to back. Place some cloth agains the glass and slowly hand tighten the clamp. Make it so its just snug dont over tighten!!! Get some sideing snipes and cut the middle brace out so your left flush with the inside plastic rim. Get some glass cut the same width as the plastic brace. Silicone that into place of the removed brace. Let it cure for a few days with the clamps in place. After this you should be fine. Shouldnt have to do anything with your tank to do it. Make sure you do have ventalation, like a fan, blowing across your tank while the silicone is cureing.

 

[MadTownMax]

I replaced the center brace on my tank with a piece of 1/4" acrylic, about 2" wide - the previous owner had used 1/8" and it had bowed, so if going this route, I'd recommend 1/4".

I used superglue in a special pack that included a plastic "activator" this created a very strong bond between the existing plastic rim and the acrylic - using a small screwdriver I could not separate the acrylic from the rim without first chipping away the acrylic.

I also made sure that my halide was at least 10" above this brace, so that it would not damage the plastic - it looks like you have your lights mounted pretty close - you may thing about going a bit higher - if a fish ever splashes a large amount of water onto the bulb it can shatter - YMMV

HTH

 

[dbates]

yea? how high would you all recommend having the lights above the water surface?

 

[ostrow]

10-12"

 

[MadTownMax]

If just over water, I know a lot of people go as low as 6". I know reef-optics reflectors are optimized to have the bulb 8" above the water's surface (this is from a company spokesperson) and 8" might even be OK over the acrylic - but for safety's sake, 10" is a more agreeable distance.

FWIW - Most acrylic tank manufacturers recommend 12" from a halide bulb to their acrylic tank bracing to avoid premature cracking.

I only removed the brace so that I could light my tank w/ a single halide - and I found that the closest I could mount the bulb was about 12"due to heat issues (this was in a non-air conditioned house )