Diy dropoff tank

[Edlanier]

So I got a nice 20 gallon junk aquarium to try and see if I can make my own version of a drop off tank. Because I dont have 800 dollars to buy a 15 gallon version.

So I sketched it all out and took off the short piece of glass on the side. And I did so without removing a lot of the black bracing on top.

Now my issue is that I did not forsee the issue I would have. I thought I would just slip in new pieces of glass and call it a day. So what I ran into was how would I connect the new glass in the old aquarium and have it hold the best.

My initial thought was have the new piece slide in and have it slightly overlap the old glass and silicone the edges there. I would have a new piece of glass come up about halfway up and act as the wall of the aquarium I just took out and then have the new connecting bottom part of that glass joined there. That part I know is ok. The walls of the new piece is the tricky part. As I already said I thought I could just slide them over each other and do that but now I'm thinking maybe there is a better way.

Not the original sketch but a crude mock up. Hope it conveys my thought process.

Thoughts?

 

[UncommonSense]

The primary issue you’ll run into is hydrostatic pressure:

.433PSI per-vertical foot of water column, for distilled fresh water, .444PSI/ft for saltwater!

— for this reason, tank walls and bottoms get progressively thicker as the tank gets taller (deeper)!

This can work, but it does require the lower tank to be made of much thicker material than the upper tank…

Lapping the lower tank inside the upper tank’s walls with silicone is likely your best-bet, but also isn’t a sure fire way of pulling this off unless executed precisely!

Leaving a “lip” of lower tank wall glass sticking straight up from the upper tank’s floor works great to retain sand in the upper tank, and adds a lot of rigidity to the odd shape!



Further reading:

https://www.reef2reef.com/threads/calling-all-engineers-and-tank-builders.1153171/

 

[Edlanier]

The primary issue you’ll run into is hydrostatic pressure:

.433PSI per-vertical foot of water column, for distilled fresh water, .444PSI/ft for saltwater!

— for this reason, tank walls and bottoms get progressively thicker as the tank gets taller (deeper)!

This can work, but it does require the lower tank to be made of much thicker material than the upper tank…

Lapping the lower tank inside the upper tank’s walls with silicone is likely your best-bet, but also isn’t a sure fire way of pulling this off unless executed precisely!

Leaving a “lip” of lower tank wall glass sticking straight up from the upper tank’s floor works great to retain sand in the upper tank, and adds a lot of rigidity to the odd shape!



Further reading:

https://www.reef2reef.com/threads/calling-all-engineers-and-tank-builders.1153171/

So to clarify. When you say lapping do you mean what I referred to about having the two pieces of glass overlap? If so is it best to silicone all around that portion? Inbetween the glass I mean?

And yes I was going to add a lip to the piece. Although it will be mostly rockwork on top for more of a tide pools vibe.

So as of right now I have 5 pieces of glass going in. Would it be best to add another to better hold the thing together? If so how and where? Also its just a standard 20 gallon tank. I am not worried about the thickness of the glass. Just the way it should fit together. Ill have a base built to hold up the upper portion as well.

 

[UncommonSense]

So to clarify. When you say lapping do you mean what I referred to about having the two pieces of glass overlap? If so is it best to silicone all around that portion? Inbetween the glass I mean?

And yes I was going to add a lip to the piece. Although it will be mostly rockwork on top for more of a tide pools vibe.

So as of right now I have 5 pieces of glass going in. Would it be best to add another to better hold the thing together? If so how and where? Also its just a standard 20 gallon tank. I am not worried about the thickness of the glass. Just the way it should fit together. Ill have a base built to hold up the upper portion as well.

Ah! I see what you mean!

Yes, I mean overlap the glass, with silicone between each pair of panes around the entire joint, ideally all assembled at once so the silicone is applied all at once, ensuring that it all adheres together well!

(Don’t overlap more than ~ 5/8”-3/4” of glass or the silicone cure time goes up dramatically!)

 

[MnFish1]

So I got a nice 20 gallon junk aquarium to try and see if I can make my own version of a drop off tank. Because I dont have 800 dollars to buy a 15 gallon version.

So I sketched it all out and took off the short piece of glass on the side. And I did so without removing a lot of the black bracing on top.

Now my issue is that I did not forsee the issue I would have. I thought I would just slip in new pieces of glass and call it a day. So what I ran into was how would I connect the new glass in the old aquarium and have it hold the best.

My initial thought was have the new piece slide in and have it slightly overlap the old glass and silicone the edges there. I would have a new piece of glass come up about halfway up and act as the wall of the aquarium I just took out and then have the new connecting bottom part of that glass joined there. That part I know is ok. The walls of the new piece is the tricky part. As I already said I thought I could just slide them over each other and do that but now I'm thinking maybe there is a better way.

Not the original sketch but a crude mock up. Hope it conveys my thought process.

Thoughts?

Your drawing doesn't make sense. However - all you need to do to precent an issue with hydrostatic pressure is just putting crushed coral/live rock behind your drop-off