Glass top for reef?

[aceiswild7]

i never used the glass cover for my 125 reef but now i have a 180 that i set up and it came with a glass cover for it. im just curious whether or not anyone else uses them? do they trap too much heat or take away from the lighting in any way?
just curious what everyone else out there is doing
thanks

 

[maroonclownfan]

Glass tops will do both, trap heat and weaken light intensity.
Some people may argue that, but I think the majority will agree.
Not to mention the salt creep will make them a mess over time.
JMO...MCF

 

[hookedonreefs]

I don't know about weakening light intensity, but I know they trap heat. I have versatops on my tank. I prop them open with the veturi connection for my powerheads. I don't run air through the powerheads so they are spare parts. Doing this dropped the temp about two degrees. As for salt creep I don't have any. I clean the tops every weekend as part of maitenence. I use them because my lights are only about six inches from the top of the tank. I don't want water to splash or fish to commit suicide.

 

[maroonclownfan]

It has been discussed in other threads about glass tops filtering out some light. Maybe someone else can add more.
I stop using a glass top on my tank because of the maintenance, constantly wiping it off, and because I got better air/water contact without it, plus better temp. stability.
One thing I also noticed was that the evaporation was greater which required more frequent water top-offs.
MCF

 

[cincyreefer]

Glass tops SHOULD NOT be used on reef tanks. Not only do they trap heat, but they also diffract much of the light and block out most of the UV rays that corals require. Without a glass canopy, you also get better oxygen exchange.

 

[nm reef]

Topless here also...better gas exchange/less heat/lower maintenance...definitely major plus to remove the glass tops and let the reef breathe!

 

[jumpfrog]

I guess those of you who go "topless" use egg crate to keep the fish in and in some cases to support the lights. Does it really work well?

 

[bonermeister]

Topless.

 

[polarpooch]

I used cut acrylic from Home Depot (about $6 bucks worth and they cut it for you) to lay lengthwise across my tank in the front and back to keep my jumpers in. Cheap and effective.

 

[tangman99]

Topless here also.

 

[phil1964]

I go half topless. I am shy
I added the glass tops because my lights are mounted to my canopy top and only 3 or 4 inches from the water. They kept getting salt on them and one day one poped. I have the tops on but leave the front lids open. Works for me.

 

[foulbrew]

Hmmm, no suprise that most of the guys prefer topless...
I use a top on my 46 bow for several reasons and have had no problems.
The main reason is lighting. I use a lamp that has 2 96 watt PC bulbs and wanted to get the most light penetration possible. I found that I got a better more intense light with the PCs closer to the water with a glass cover than I did with just the PCs farther away. Beacause of this I wanted the PCs as close as possible without causing heating issues.
Heating is the second issue. I live in Minnesota and for most of the year the issue is not too mich heat, but to little. The lid helps keep the temperature more constant with less electricity.
Evaporation is the last but maybe not least. I have chosen to use Kalkwasser for my main calcium supplement. To do this I need at least a half gallon of water to evaporate a day ( this is the amount of kalkwasser needed daily to maintaing my calcium/alk levels in the 46).
I have drilled two 1" holes in the top to help achieve a good balance heat/evaporation and this does provide a little better environment for gas exchange than a lid with none. However, I believe I already have more than enough surface area for good exchange with my refugium and sump (and protein skimmer).
92 Corner :
I am just finishing the lid for my newest tank a 92 corner. This tank will be lit with a single 400 watt mh lamp. I do not plan on using a lid for this tank, guessing that I will be best able to balance the heat and evaporation issues without one. However I am building the cover in a manner that leaves my options open.

 

[cincyreefer]

If you are having a problem with saltcreep or want to put your PC's right on top of the tank then use plexi glass. Plexi glass allows the UV rays to pass and doesnt diffract nearly as much light as your typical glass canopy.

 

[jlem]

Glass tops SHOULD NOT BE USED ON CINCYREEFERS TANK. Now I have used acrylic tops on my reef for a while now and if you have ever seen pictures of my reef there has been no ill effects what so ever on my reef. I used glass for more than a year but went over to acrylic because of weight. I do have little spots cut into the acrylic for air movement so gas exchange is just fine. I would not use a top that seals around the tank but even an inch or two lenth wise in the middle of the tank will allow plenty of gas exchange. I won't argue about the heat because a top will increase heat but I run a fan and the temp stays around 78. Glass won't diminish the light that much or else no one with a reef could run tops which some people do and have done for years.

 

[cincyreefer]

well now you are getting into another topic: types of corals being kept. Many corals such as polyps, mushrooms, and soft corals will do fine with a glass canopy, but many clams, sps, and lps will not thrive without the needed UV rays. That is not to say that they won't live, but they might not do as well or grow much. It has been proven that glass canopy's block out UV rays (reason why you wont get nearly as bad of a sunburn if you are in direct sunlight in your car with the windows rolled up, compared to being outside) and that glass canopy's also diffract and deflect light. Doesn't mean that you can't keep corals (lps sps) with a glass canopy, just that you will have a better chance of getting them to thrive without one.

 

[cincyreefer]

I just studied light diffraction/deflection in my physics class and if someone can tell me how to put in the symbol for theta and subscripts then i can post the equation for diffraction. I can still explain this though... when light enters glass perpendicular to the glass, then all light passes through unobstructed. So if you have enough lights from the back of your tank to the front of the tank then you will get lots of good light unobstructed through the glass canopy (except for the UV rays) and the tank will have a nice coverage of intense light. However, if you dont have several bulbs evenly spread out over the tank, then the light that is entering the glass canopy at an angle will be diffracted and half of it will be reflected. The point is still that reef tanks can do fine with a glass canopy, but will be under ideal conditions without one.

 

[slowest is fastest]

FWIW
Glass traps heat
Glass gets dirty
Glass tops have been shown to reduce the amount of light into the aquarium by about 10% (article by Ivan Busko lighting article )
Glass does not in my expierence hinder the growth, health or color of any of the SPS, Clams or softies in any tank I have owned or seen.
Currently I have a heating issuse when using glass tops on my 120gallon so I do not use them.
On the 125 gallon there are three 400 watt mH 20 K radiums inside pendant lighting with glass covers. The tank is uncovered and is supplimented by two 160 watt VHO actinics. Some of the pics can be seen here
pics
SiF