I have a glass canopy for my 65G tank and was wondering what was the feeling on oxygen exchange on a covered tank. My tank does not have a canopy so the glass keeps the fish from jumping out as well as reduces evaporation. My only concern is the sufficient oxygen exchange. The sump is fully open and im imagining providing enough surface area and plenty of agitation for gaseous exchange. Is this typically a problem? In other words should I run out and order a dissolved oxygen test kit ( haven't found one locally)? Or is this a common setup that doesnt typically pose a problem?

as long as you leave a gap or 2, its not going to be a problem. The yanks typiclly dont use cover glass though

Having a sump helps.
A protein skimmer injects oxygen in the water.
Try pointing atleast one powerhead at the top to break the water, thus creating better oxygen exchange.

they will also restrict light penetration into the tank.

Bobby,
How much light do you figure is lost by using glass tops ?

i am not sure on a number, but even with metal halides it cuts down a pretty good amount of light from entering the tank. the salt creep that accumulates on them over time will also add to the light having a hard time getting through to the water.

It didn't take very long for my glass tops to scum over enough to visibly reduce the light transmission. I would clean them at least weekly with some vinegar water to keep them passing light well.

I need a par meter ! :D

Hmmm... I might just go with some black eggcrate for a cover If I can get it tp look half decent.

eggcrate does the same thing, but worse. white would be the way to go if you used eggcrate (light diffuser) for a top. it will still cut down on light penetration though. even something as thin as screen dramaticly cuts down the lighting if it is between the light and the water.

Bobby,
How much light do you figure is lost by using glass tops ?

lol, how much do you really want to know???? Cause i dont even pretend to completely understand the formulas involved.

Technical within the realm of simple.

5 main factors govern all.

1st - temp, creation + ambient
2nd - total mass of diffused atoms
3rd - mass viscosity & moisture content
4th - projected wavelengths intensities.
5th - distance divided by time

ouch, lets start counting the formulas that make the variables shall we..lol, i think not!


Basicly from what ive seen & read- and i could be wrong here , but anywhere from 3 - 15 mm, your looking at a range of 65% - 90% light transmittance, with UV transmittance about 20% lower. as a benchmark since starphire glass is universal, they sit somewhere between 70 - 80% depending on thinkness.
All glass manufactures must provide this data, so if your keen to see it yourself, hop on the phone to your local supplier. Hope that kinda answered your question

When I first set up my tank i was told that i needed a glass top. Very i felt it was a pain to clean, plus it kept any heat in the tank. This might no matter but living in Florida is was a big deal for me. I actually owned a chiller for my tank before i owned a heater!

lol, how much do you really want to know???? Cause i dont even pretend to completely understand the formulas involved.

Technical within the realm of simple.

5 main factors govern all.

1st - temp, creation + ambient
2nd - total mass of diffused atoms
3rd - mass viscosity & moisture content
4th - projected wavelengths intensities.
5th - distance divided by time

ouch, lets start counting the formulas that make the variables shall we..lol, i think not!


Basicly from what ive seen & read- and i could be wrong here , but anywhere from 3 - 15 mm, your looking at a range of 65% - 90% light transmittance, with UV transmittance about 20% lower. as a benchmark since starphire glass is universal, they sit somewhere between 70 - 80% depending on thinkness.
All glass manufactures must provide this data, so if your keen to see it yourself, hop on the phone to your local supplier. Hope that kinda answered your question

Verriann,

SORRY I ASKED !!! :o

I do use my glass top because it is the easiest way to have a light on my corner tank. You could hang it like a pendulum or get some sort of bracket but if I waited for that my Solaris would still be sitting in the box!

I have glass suspended about 3" above the water surface so there is still air exchange. I did this within my hood. It is just regular window glass I had cut. 3/32" or 2.4mm. My corals seem fine with the light from 175W MH through the glass. At this height they dont get much on them from the water. I mostly clean them every two weeks because of the dust accumulating. Maybe I can blame my diatom farm on the glass or dust. :D

I do not use the glass top for my tank. I use egg create but I cut a large hole in the center of the eggcreate. This allows for protection from carpet divers but lets in as much light as I can still get in.

I saw somewhere (not sure if it was here or not) someone who built a nice top with vinyl window screen frame and then used a black mesh with 1/2" or so sqaures. Protected the jumpers and had almost no light loss. It's something you could get from any Lowes or HD or even have a screen shop make up for you I'm sure.