# Am I better off without glass covers?



## wagz (Aug 6, 2012)

Hey there,

I justed started using the glass covers that I had cut to size to allow room for canister hosing and the fact my hob is on the side, its an hos.

I have injected co2 and from what I read covers stop some of the loss due to mixing with o2. Obviously it helps with evaporation and jumpers too. Only lost one lf zebra danio a few months ago during an escape attempt.

I noticed it is not as bright in the aquarium as before. I am working with 2 watts/gallon on my 75g, and not even sure if its that because my odyssea t5 may not put out the rated amount because of cheaper ballasts etc. So I can't afford to lose much light. I do plan to buy an additional light in the future, but I'm still in debt over everything I've done so far.

I have been researching and have conflicting thoughts. Some say you lose very little 5%, some say more including all UVB rays(I don't know how important UVB is in freshwater plants). Some say they never use them, some say use with no problems. 

Also the glass is green from the side, so it's the typical iron content one, which diminishes more light. 

Does the blockage of light outway the benefits to evaporation, and or co2 preservation using glass covers?

Thanks.


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## niko (Jan 28, 2004)

Just do away with the glass.

One reason being that over time the glass accumulates deposits and unless you rinse it every day it will get cloudy eventually blocking much more light.

Loss of CO2 is not an issue unless your surface is being stirred very strongly. Evaporation is something to deal with - all cool looking open top rimless tanks need to have the ends of all 4 glass pieces cleaned daily or you risk them getting dull and possibly impossible to clean.


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## Seattle_Aquarist (Mar 7, 2008)

Hi wagz,

I responded to a similar question on another forum about this subject and the results I got from a PAR meter. The results were interesting. It was a standard 30 gallon (36" length) with an 2X36 watt (6700K) AH Supply kit over a Aqueon Versa-Top. With new bulbs and no glass top the PAR = 110; with cleaned Versa-Top in place PAR = 101; with "dirty"* Versa-Top in place PAR = 96. All readings were taken with new bulbs @ substrate level about 13 inches below the fixture.

*dirty = lots of dried water spots on top; some "etching"; condensation; dust


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## wet (Nov 24, 2008)

Thanks for those numbers. That drop off is interesting.

One more reason for open top: emergent plants!


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