Place lens in constant contact with water?

[Runner]

I am retrofitting my LED fixture into the hood of my JBJ lighting 24G nano cube. Both the heat sink and the fans are 1" thick. This leaves about 1/2" or less air gap from the bottom of them to where I would install the acryllic protective cover (the one I am fabricating) if I made it flush with the bottom of the JBJ nano hood. If I lower the cover/lens any more, it will be splashed. Even if I leave it tight with the LEDs and fans, there will be quite a bit of splash that will require maintenance.

My question is this: Can you think of any reason why I should not lower my acryllic protector down about another 1/2" or so and place the bottom surface in constant contact with the water surface? It will be water-tight so I am not worried about that. I hope to gain sufficient air circulation without seriously modifying the heat sink and replacing the fans. And I can live with the loss of a shimmer effect -- I've been on PC bulbs for ages.

Thanks.

 

[macclellan]

My question is this: Can you think of any reason why I should not lower my acryllic protector down about another 1/2" or so and place the bottom surface in constant contact with the water surface?

Seriously reduced surface area for gas exchange, which is a big deal especially since you don't have a skimmer (I've killed fish this way in FW by overfilling so that the water was in contact with the glass cover). All you get is the back chambers then for oxygenation at night. Adding an airstone on a timer reversing the photocycle *could* counterbalance the problem.

 

[Runner]

Good catch. I would still have the fans constantly going for air exchange across about half the water suface area which would not be so displaced. And I do only have three smallish fish. But I see the point and would consider an air stone if I do it this way.

 

[Engloid]

Just some random thoughts...

You will probably not get any shimmering effect from the lights, since you would have no surface waves. One good thing is that you would have less problems with the top getting dirty ...except for ocassional cleanings for algae. But when the algae is off, you will probably get more light into the tank because you will eleminate one surface that reflects the light back upwards.

 

[macclellan]

Oh, I was imagining the whole front area being covered, so 1/2 is not as bad.

 

[DevinWolfe]

The only concern I would have is a SLIGHT increase in heat. Not so much due to the LEDs being warm, just the reduced surface area would allow for less heat to escape. And the cleaning thin that Spencer mentioned, but that wouldnt really be a big deal since you could easily lift the nano's lid from one side to scrub it clean.

I have PCs and have to run a heater in my 29-BC so you likely wouldn't have any issues with heat anyway, just thought I'd throw it out there.

 

[Runner]

Looks like I am going to start cutting acryllic tonight and am still not sure which way I'll go on tihs. This issues are:

1. Additional heat: Mitigated by fans moving air
2. Algae growth: Possibly rapid/severe growth. Maintenance concern for scratching over time from the cleaning.
3. Air exchange: Cutting down half my surface area and really don't want to put in an airstone.
4. No shimmer: Would like to keep it but can live without it.
5. Mounting: Problem with screw locations if do this.
6. Light levels: Increased because no reflection off water surface.

A big plus, though, is that I've never seen it done and it might be cool to try it. If I don't like what I get, it will not be too hard to remove a little bit of acryllic and bring it the cover out of the water.

Still not sure, though -- let's see how far I get tonight.