Rimless Tank Lid Questions

[Shane L.]

I'm putting together a rimless tank (39" x 12" x 12") and will probably add a lid to it. Being such an odd size, I know I need to do a DIY lid. Nearly everyone I've seen online makes lids from either glass, polycarbonate or acrylic and then hang them inside the aquarium with clips, so the lid sits down and inside the inner edges of the tank. My question is, why does no one sit the lid directly on top of the top edge of the aquarium (not inside it with clips)? Seems to me it would be more secure sitting on the top edge rather than clips and would square up the look with the edges of the tank nicely (obviously would have cutouts for filter, tubing etc.). But is there a reason why I shouldn't just sit the lid directly on the aquarium edges rather than using clips? Will condensation seep under it and run down the sides of the glass?

Also, I see online some people drill a few large holes or dozens of small ones for air circulation under the lid (usually in acrylic), and others don't. Assuming the lid has a few cutouts for filter, tubing, heater cord, etc. and is not completely air tight, would you still recommend adding a few large holes or several smaller ones for air circulation? Seems like that might defeat the purpose of trying to eliminate evaporation by giving water more holes to escape from?

[Zenzo]

I use the polycarbonate twin wall panels as lids. For my rimless tanks, I rest them on the edges as you suggested. As far as holes, the only holes I have in the lids are for the airline tubing to pass through. These seem to suffice as far as air getting in and out, especially because I run an airline to every tank.

I hope this helps.

As far as the clips, I believe that this is for for aesthetics. 

[Ragnarok12]

I am a big fan of having a lid set on the top of the tank as opposed to within the tank. And I agree with Zenzo that the latter is mostly about optics. I have a 12 gallon tank with similar dimensions to yours (something like 8x8x36, I forget) and I actually decided to get a local glass shop to custom cut a lid for it that sits right on top of the tank. They cut it with sturdy and clear 1/4 glass, beveled the edges so that it looks REALLY nice, and even cut out a notch in the back for my HOB. The whole piece cost me around $40. I then put rubber bumpers on the corners of the tank and that created a nice 1/4 inch gap that I can run air line tubes or heater cords through.

The pros of this setup are that it looks great, is sturdy, is easy to clean with the wipe of a towel, and doesn't sag or discolor over time. It is also very easy to put an LED light on top of. The cons are the cost and the fact that I have to slide the lid to the side to feed or remove the lid altogether to clean. The pros far outside the cons in my opinion though. I would highly recommend for your setup. Any local glass shop should be able to do it. Here are some pictures of what my setup looks like:

 

[Shane L.]

@ZenzoThanks for the info, good to hear sitting it on top edge is working for you.

[Shane L.]

@Ragnarok12 Thanks for the info and photos. Your tank and lid look amazing and that's exactly what I would like to do. And I like the tip of using the rubber bumpers. I'll look into local glass shops for pricing! Thanks again for the photos.

[Andy's Fish Den]

I have a rimless 93 gallon cube and the glass top sits on clips and the top is inside the tank flush with the top of the side panels. I like the idea that @Ragnarok12showed above. I do see droplets of condensation on the glass top, and one thing I would be afraid of is that if the tank and/ or the top is not perfectly level, those droplets would slide to one side or the other and potentially drip down and run down one of the sides of the aquarium, which could lead to potential damage to the stand that the tank is siting on. Other than that, I like the looks of it.

[Ragnarok12]

On 11/10/2021 at 6:43 AM, Andy's Fish Den said:

I do see droplets of condensation on the glass top, and one thing I would be afraid of is that if the tank and/ or the top is not perfectly level, those droplets would slide to one side or the other and potentially drip down and run down one of the sides of the aquarium, which could lead to potential damage to the stand that the tank is siting on.

That's a valid concern. I think the beveled edges on the glass sheet may help wit that. I've had this tank set up for around 10 months and I have never actually had any dripping or running down the sides from the condensation. I also have very little evaporation from this tank, so the gap between the lid and the tank don't seem to be facilitating water loss at all.