Lighting Question - Glass penetration

[SFMAquariums]

Hello,

I am looking for some help with a tank I am building. I bought a house last year with a 225 gallon aquarium built into the basement wall. I am currently trying to get it setup for my first saltwater tank!

I have been starting to look at lighting options & have identified a bit of an issue with my tanks design. The central portion of the roof of the tank is reinforced with a large piece of glass (see picture). I can therefore hang lights over the right & left open portions, but I worry about the lack of light to the middle portion of the tank.

I don’t think I can cut that glass away as I worry it would affect the structural integrity of the tank. I am not sure if a high enough powered light would still offer enough light to penetrate through the glass, as it is quite thick. I am wondering about the feasibility of cutting a smaller hole in the center of the glass that I could hang a light over, but am also not sure of the efficacy of this & also worry if it would affect the tanks integrity.

Does anybody have any experience dealing with a similar issue? Or any thoughts on solutions?

Any feedback would be greatly appreciated!

 

[wvned]

Most large tanks have cross braces and you avoid putting a light directly over one. The braces on my tank are black and opaque.

 

[SFMAquariums]

Most large tanks have cross braces and you avoid putting a light directly over one. The braces on my tank are black and opaque.

Oh wow okay gotcha. I didn’t expect that! Do you find that you have issues with corals & other things growing under your cross brace? Or does the light manage to still be sufficient?

I was originally planning to use black sand as my substrate but had been reading some possible issues with this type of sand & also read that lighter colour sand can help reflect light & increase PARR so was planning to go in that direction instead in case that also helps!

 

[wvned]

All lights produce a cone of usable light. Adjusting the height and spread of 2 fixtures lets you put the cross brace outside of the cones shining down and avoids casting a shadow into the tank. The corals are then unaffected by it.
If a coral grows up to your glass cross brace I expect enough light will go through it that it will be fine as long as it is kept reasonably clean.
I have never used black sand. There were always rumors of it containing metals.

 

[griss]

Years ago, I had an old Oceanic 200 gallon tank that had a brace like that in the center. My lighting was (3) 250 watt Iwasaki Metal Halides and (2) 400 watt Radions. One of the 250 watt Iwasakis was directly over the glass brace. There was definitely loss of light under the brace so, I just kept lower light corals in that area of the tank.

The really negative thing, the brace would get salt creep on the underside and cleaning it was a pain.

 

[wvned]

The 240 has 3 cross braces, the 180 2 and the 75s have 1. Its just something you deal with.

 

[oreo57]

Hello,

I am looking for some help with a tank I am building. I bought a house last year with a 225 gallon aquarium built into the basement wall. I am currently trying to get it setup for my first saltwater tank!

I have been starting to look at lighting options & have identified a bit of an issue with my tanks design. The central portion of the roof of the tank is reinforced with a large piece of glass (see picture). I can therefore hang lights over the right & left open portions, but I worry about the lack of light to the middle portion of the tank.

I don’t think I can cut that glass away as I worry it would affect the structural integrity of the tank. I am not sure if a high enough powered light would still offer enough light to penetrate through the glass, as it is quite thick. I am wondering about the feasibility of cutting a smaller hole in the center of the glass that I could hang a light over, but am also not sure of the efficacy of this & also worry if it would affect the tanks integrity.

Does anybody have any experience dealing with a similar issue? Or any thoughts on solutions?

Any feedback would be greatly appreciated!

Glass, even dirty, only cuts like 15% of your PAR.
AI's take..

AI Overview



Glass covers on aquariums
reduce PAR (Photosynthetically Active Radiation) by roughly 10-30% or more, depending on cleanliness, salt creep, and condensation. While they effectively minimize evaporation and prevent fish from jumping, they can reduce light penetration and restrict gas exchange. Regular cleaning is essential to maintain high light levels, or consider switching to a mesh lid.
Key Considerations for Glass Covers and PAR Loss:

• Light Reduction: Even clean glass blocks some light. Studies suggest a 10% reduction when clean, rising to 30% or higher with dirt/salt creep.

And yes, do not mess with the brace...