need expert advise on glass tops on aquariums

lousybreed

Aquaria Central Site Controller
Sep 7, 2004
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Bay Area, CA
Will 1/4" glass tops greatly reduce the light spectrum? Do you use glass tops or open tops like they do for reef aquariums? I have 1/4" glass tops and i am debating whether to use them
 
Use the glass top. My light actually has a built in acrylic cover on the bottom and sits over a glass strip. My plants are growing faster than I could have believed and I only have 65 Watts of PC lighting over a 29 gallon that is rather tall.
 
Found this info on the Krib. I rember reading it before, so I searched for it quick and found it.
Link!
According to this, a glass top will lose ~10% of the light. On a reef aquarium, where no inhabitants will commit suicide, it works fine to leave no cover on. If you have fish, you probably want the cover, to prevent jumpers....

Another thing that a cover will do is prevent water from getting into your light, and to keep the water from evaporating. IMO, keeping the water out of the light, or keeping the light out of the water :eek: is worth losing the 10%.....
 
Glass and water (assuming that both are clean) don't really block light. They do however bend the light rays. I think that the index of refraction of glass and water are .93 or something close to that. Anyway, it means that the light will be bent at an angle of about 21 degrees. Which isn't very much at all. And the light hits the water at all angles so there aren't any dark spots in your tank.

If your concerned, reflectors really help brighten up the tank because they add more angles to the way the light hits the water. So you might get a reflector if your really concerned.

Last, and more important, keep your hood clean under the lights. There can be mineral deposits (most common) and mold (also common). Both of these block light. Blocked light is much worse than the light rays being bent.
 
I don't use glass tops. I guess its just my preference. My fish don't jump out and i clean my tank frequently enough that evaporation does not really effect me. I just like the look better and i hate messing around with glass tops.
 
I do a 15 gal. change in my 55 a week. I usually add somewhere around 18 +, especially in the winter. For some reason, the water will evaporate out of my larger tanks that are only partially covered at an extremely high rate. My 42 hex. tank will lose 1 gallon a day or more(Most of the top is covered, except a 4" strip at the back). For me, it is a big thing w/ evaporation, as in my room, it is usually ~77 deg. F, and probably around 75% + humidity.....
 
Harlock said:
Use the glass top. My light actually has a built in acrylic cover on the bottom and sits over a glass strip. My plants are growing faster than I could have believed and I only have 65 Watts of PC lighting over a 29 gallon that is rather tall.

I purchased the plastic egg crate 4' x 2' for about $5 at home depot. I cut it to fit the top of my tank (regualr scissors work for this) and then ordered the legs for my coralife light. It is perfect (for me anyways). The fish can not jump out. I have a 90 gallon so I have to replace about 1 gallon of water every two days. I use RO for this so that the disolved minerals do not become to concentrated.
 
Jason01 said:
I do a 15 gal. change in my 55 a week. I usually add somewhere around 18 +, especially in the winter. For some reason, the water will evaporate out of my larger tanks that are only partially covered at an extremely high rate. My 42 hex. tank will lose 1 gallon a day or more(Most of the top is covered, except a 4" strip at the back). For me, it is a big thing w/ evaporation, as in my room, it is usually ~77 deg. F, and probably around 75% + humidity.....

The water evaporates in relation to the humidty and surface area of your tank. The water in a taller tank will evaporate at a slower rate than a longer tank. That is, a 20 gallon long will evaporate faster than a regular 20 gallon. The long has less surface area and isn't as deep.

There is almost always more humidity in the summer than in the winter. So thats why your tank's water evaporates faster in the winter.

Also, if your tank is in the top of your house and not in the basement, it my lose water faster. Basements are generally humid.

A canopy is probably the best way to prevent exaporation followed by the hood. It all depends on the amount of open sapce in the hood or canopy too.

There was a product made a few years ago that would fill up your tank and do a water change constanly. It ran at a very slow rate. It would change about 5% of the water every day. All you had to do is plug it into your faucet. One of those would probably help your evaporation problems. I don't remeber what its called, but I seen it in that fish place's catalog several years ago.
 
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