Glass tank cover and lights

[skennelly]

What is everybodies outlook on having glass covers on their tanks and the effects on lighting. I have 440 watts of VHO lights on my 90 gallon along with all-glass glass tops. My lights are mounted in an all-glass wood canopy so the lights are about 6 inches above the water.

It seems to me if I remove my glass tops the light seems more intense. But I have heard glass tops help with evaporation and salt creep.

any thoughts?

[Birdlady]

My take...

I run an open top because it helps with oxygen exchange at the water surface, and helps keep tank cooler.....flip side...higher evaporation rate and if something is splashing the water surface, you get salt creep.

I have the water 'boiling' on the top but no splashing.

My light hood is enclosed with a piece of plexiglass. Glass and plexiglass does reduce the amount of light passing through, no doubt. My light is about 4" from the water surface. Less light, but closer to the surface....and no busted bulbs or damage to the lights from humidity and salt water

[skennelly]

Another thing I notice is that salt deposits build up on the glass tops and I believe it blocks light out. I usually clean them off every 2 weeks or so.

[Midnight_Madman]

But if you dont have any glass, doest that same salt deposit go onto the bulbs?

[jnbahwkins]

As far as glass goes i am using glass because it drastically reduces evaporation and holds heat in keeping my tank temperature very stable.I figure my sump and protein skimmer will inject enough oxy.

But the glass i am going to use is being cut at a glass shop a couple blocks away from my house.I just called them today.
it is called Starphire glass,it is crystal clear optical quality glass that passes like 99% of light ,there is no green tint also known as optical quality glass.It is the same glass imax theaters use in projection booths.

I will have to keep it clean like other glass but at least it blocks little to no light.

[Midnight_Madman]

Actually acrylic or plexi is just as clear I believe..? but it may actually be more expensive..

[jnbahwkins]

acrylic is very clear but it scratches easily.since it is going to be used as a tank top it will need to be cleaned often,i think glass will hold up better to that abuse and the starphire glass is more expensive.but it is not that bad.it will cost me about 40 dollars

[JohnO]

I'm the same as BL, don't use a glass top at all :-)

John

[Midnight_Madman]

Once I get my new MH lights I have a lot of desiding on what im going to do also..
Right now I have a AGA glass canopy top, but if I have the halides a few inches above that glass, wount it reflect off of it too much?

[Birdlady]

MM, I believe you got the HQI's?...and if I am not mistaken (which sadly, I often am LOL) I think you need to run some type of UV filter (glass, plexi, something) to prevent excess radiation.

The bulb type metal halides have the glass bulb doing that job.