Will this Lighting setup Warp/Crack my acrylic tank?

[Timothy Tom]

I am considering adding a DIY 150 Watt HQI 20K lighting fixture next
to my 250 watt 10K fixture. The purpose of this is mainly to get a
little bluer color to my tank as opposed to a need for additional
lighting wattage. There is no room for any other type of fixture that
I can find to fit in the space that I have (VHO or PC) . The problem
I have is that the only space for a new fixture would place the bulb
about 4" away from my some of the top acrylic bracing for the tank. I
have heard horror stories that the heat of an MH will eventually crack
acrylic and destroy the tank. I will place a glass shield between the
bulb and the tank. Any opinions on whether a 150 watt HQI MH place 4"
above my tank bracing with a glass shield will cause a problem?

[Marc Levenson]

Hi Timothy Tom,

That is really close to the water. Is there a reason you are keeping it that
close?

I do know that you can add a secondary acrylic piece over the original, using a
small spacer betwixt the two. This allows a little ventilation, and the added
piece gets the brunt of the heat. It can crack and be replaced easily.

Marc


Timothy Tom wrote:

> I am considering adding a DIY 150 Watt HQI 20K lighting fixture next
> to my 250 watt 10K fixture. The purpose of this is mainly to get a
> little bluer color to my tank as opposed to a need for additional
> lighting wattage. There is no room for any other type of fixture that
> I can find to fit in the space that I have (VHO or PC) . The problem
> I have is that the only space for a new fixture would place the bulb
> about 4" away from my some of the top acrylic bracing for the tank. I
> have heard horror stories that the heat of an MH will eventually crack
> acrylic and destroy the tank. I will place a glass shield between the
> bulb and the tank. Any opinions on whether a 150 watt HQI MH place 4"
> above my tank bracing with a glass shield will cause a problem?

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[Timothy Tom]

Marc Levenson > wrote in message >...
> Hi Timothy Tom,
>
> That is really close to the water. Is there a reason you are keeping it that
> close?
>
> I do know that you can add a secondary acrylic piece over the original, using a
> small spacer betwixt the two. This allows a little ventilation, and the added
> piece gets the brunt of the heat. It can crack and be replaced easily.
>
> Marc
>
>
>The reason that I am mounting the MH lights so close to the surface
of the water is that the MH lights are retros into an existing hood
which was originally intended to house VHOs only. Your idea of adding
another piece of acrylic though is something that I had not thought
of.