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Sven 01-14-2003 09:57 PM

I have a glass cover between my light and the water surface and have been wandering if the glass reduces the light intensity that reaches the aquarium itself??

m.lemay 01-14-2003 10:44 PM

Yes, glass does reduce the amount of light getting to your plants. Firstly, it reflects when the light is coming at it from an angle. Even though you lights could be sitting directly on top of the glass many of the lights rays get reflected back, much like when you look at the window of a house from outside and you see your reflection. The reflection is light bouncing back at you. The other problem with glass is that it gets dirty fairly quickly which blocks the light. Dust from on top and water spots and mineral deposits from below all contribute to lost light.

I have a glass top on my tank and as soon as I build a canopy I'm getting rid of it.:hehe:

Buck 01-15-2003 02:51 AM

I removed the glass top off my tank about a week ago and everything seems to be shifting gears...
I have my lights timed to come on at noon and go out at eleven so just before I am going to bed I watch the tank for a few minutes and my plants always pearled a bit at the peak but now it is UNREAL !
My wife even asked me what I changed and I said ... I Dunno...nuttin that I can think of :hehe:
Taking the glass off is the only thing I have changed !
Before seeing this post I never thought about the reflection factor of glass but I sure am a glass hater now... not to mention I love the look !
I can tell you this ...when I went to bed my poly was below surface...when I got home from work 3 stems of poly and 1 stem of Sunset were growing out of the water an inch !

Bad glass.. go away !:P

Sven 01-15-2003 08:15 AM

but if I donīt have the glass plate on, isnīt there a posibility that moisture might get on the ends of the bulbs and ruin them?

GulfCoastAquarian 01-15-2003 01:22 PM

As long as the bulbs are several inches away from the surface, moisture shouldn't be TOO much of a problem. But yes, if you go without a glass canopy, I would recommend moisture resistant endcaps.

Right now I have a glass canopy because of my Silver Hatchetfish. I've even had one jump out one night after I left the glass slightly askew, leaving just a 1/4" crack. Insane. The glass is VERY stained with mineral from my ultra-hard water and I know it is blocking some light but I love these Hatchets so I can't get rid of it.

Eventually, I am going to build a tight wood canopy and get rid of both of my strip lights. I'll definitely use some waterproof endcaps like these, though.
Coralife Endcaps

STAT 007 03-03-2003 09:02 AM

Interestingly enough though, Kim at AH Supply told me on the phone a couple weeks ago that a glass cover between the lights and the water is actually GOOD and HELPS along with those awesome AH Supply reflectors. I think he was implying that the glass acts as a diffuser, which is good here. I'm not saying that he's right or wrong and it's certainly hard to say that he's right in spite of the real-world evidence you guys just gave us, but I just thought I'd throw this out there. :)

fishpoop 03-06-2003 03:57 PM

I'm going to start to build my new hood should I use glass to cover the tank or not? I'm using AH supply lights. How much more evaporation do you get without glass, over a week?

m.lemay 03-06-2003 04:11 PM

I took the glass off of my 75 gal a month ago and I like it much better and so do my plants. I got negligable evaporation with the glass on, but with the glass off I lose about 1 inch of water over the course of a week. Evaporation rate is dependent on relative humidity in the room. Right now the house is really dry because its cold outside and the heat is cranking in the house. The evaporation rate will probably less in the spring. It doesn't matter much to me since I do a 30-50% water change every week anyway.


corvus 03-06-2003 05:08 PM

Inso far as corroding endcaps goes, here's my deal. I have a 45 in my basement with a 2 bulb shop light fixture over it, hanging from the ceiling by chains. it sits maybe 3 inches off the water, nothing has corroded in 3 years, with no glass cover. that tank loses water to evaporation at a ridicuolus rate, sometimes as much as a half inch per day.

aquaphish 03-06-2003 07:37 PM

I feel that having a glass cove will not have an effect on lighting as long as the glass is kept very clean. That is why I removed my glass!!! I'm too lazy to keep it clean!!!

I made my hood and have the lights around 4 inches from the water surface in addition to a very large open section in the back of the hood to help in air circulation which keeps the humidity low in the hood. I will be adding some fans before the summer to keep the temp. down too.

Work In Progress 03-06-2003 09:11 PM

:drool: Ok for all of you advance aquascapers, I am drooling over all of this glass yall are removing. Anyone interested in maybe recouping a little cash for that old glass? I need glass for my 55g w/center brace. It is my next step in bettering my light situation. Heck a donation would be even better, Ha Ha Ha!
Glass tops around here start @ $30, so trying to find a deal...


STAT 007 03-07-2003 12:19 AM

STARTING at $30? Where are you shopping? Look online at places like and others. You should be able to find some pretty good deals. :)

Work In Progress 03-07-2003 05:57 PM

Well got my Drs Foster Smith catalog yesterday and found a perfecto for $22. Sounds good till you tack on that $8 shipping. Ha Ha, then I am right back at about $30 give or take. Oh well, might just have to spend all of my little allowance this week. :cry:


anonapersona 03-07-2003 07:26 PM

The trick is to save up until you need several things from an online source, then shipping on the second and third thing is free, essentially, and you are actually saving money. If you only need one thing and you need it now, you may as well support your local fish store.

Work In Progress 03-07-2003 08:11 PM

:roll: Unfortunately I suffer from the, "I Want It Now!" syndrome, and saving $30 a week for some of the bigger things, feels like FOREVER! :roll:
If only my money matched my wants...

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