Turning 120 gallon with 2 corner overflows into a peninsula tank.

Tonycass12 · Nov 30, 2022

I was lucky enough to find a 120gal system 4'x2'x2' tank that was being given away for free this past weekend. The tank is in good shape and I'm getting everything cleaned up now. I was planning on upgrading to a peninsula tank before this one fell into my lap but now im getting curious as to how hard it would be to get rid of the overflows in this 120 and turn it into a peninsula tank. The overflows are plastic and look to only be siliconed in. I think its an old Marineland or aqeon aquarium. I could probably just cut them right out and scrape the silicone. I think ill be safer leaving a little chunk of the overflows and not messing w the silicone where it meets in the bottom corners. Then could I just plug the bulkheads? Or would I be better off removing the bulkheads and siliconing a 1/4" thick chunk of glass over them?

If I can get those removed and the holes plugged ill drill for another overflow and returns on one of the short ends.

Any opinions or pointers on this project?

Brad_95 · Nov 30, 2022

the overflows can be somewhat of a pain to remove, but that's just on a case by case basis. I'd recommend getting a couple gauges of guitar strings or just a basic metal wire and a pair of welder's gloves for grip. Should be thin enough to run through the silicone and separate it from the glass. when in doubt, heat the wire up then run it, itll definitely cut like butter.

Brad_95 · Nov 30, 2022

and for plugging, either plan works. but if you're going to go the glass route, make sure to silicone and place the glass INSIDE the tank and not the OUTSIDE. Big reason is for the water pressure, it'll only push down on the glass inside rather than pushing out on the outside.

Tonycass12 · Nov 30, 2022

Y

Brad_95 said:
the overflows can be somewhat of a pain to remove, but that's just on a case by case basis. I'd recommend getting a couple gauges of guitar strings or just a basic metal wire and a pair of welder's gloves for grip. Should be thin enough to run through the silicone and separate it from the glass. when in doubt, heat the wire up then run it, itll definitely cut like butter.

After reading some other posts like this I did see some people having issues with some overflows being glued and siliconed. Luckily for me mine look like they are just silicone I was able to push a razor behind one side already. Thanks for the wire tip though that may speed things up.

death-by-reef · Nov 30, 2022

excited to see how this turns out. are you going to do a build thread?

Tonycass12 · Nov 30, 2022

death-by-reef said:
excited to see how this turns out. are you going to do a build thread?

Yep figured I would start here in the DIY section. Once its all togeather I will start a new build thread once water gets in the tank and I start to transfer all my fish and corals. Ill make sure to post a link for it in this thread!

Dburr1014 · Nov 30, 2022

Tonycass12 said:
I was lucky enough to find a 120gal system 4'x2'x2' tank that was being given away for free this past weekend. The tank is in good shape and I'm getting everything cleaned up now. I was planning on upgrading to a peninsula tank before this one fell into my lap but now im getting curious as to how hard it would be to get rid of the overflows in this 120 and turn it into a peninsula tank. The overflows are plastic and look to only be siliconed in. I think its an old Marineland or aqeon aquarium. I could probably just cut them right out and scrape the silicone. I think ill be safer leaving a little chunk of the overflows and not messing w the silicone where it meets in the bottom corners. Then could I just plug the bulkheads? Or would I be better off removing the bulkheads and siliconing a 1/4" thick chunk of glass over them?

If I can get those removed and the holes plugged ill drill for another overflow and returns on one of the short ends.

Any opinions or pointers on this project?

There is a thread somewhere here, someone has done this already... Let me look at build threads.

Tonycass12 · Nov 30, 2022

Dburr1014 said:
There is a thread somewhere here, someone has done this already... Let me look at build threads.

I found a couple that link back to an old reef central post on removing them but those a definitely the more difficult to remove style overflow.

Dburr1014 · Nov 30, 2022

Tonycass12 said:
I found a couple that link back to an old reef central post on removing them but those a definitely the more difficult to remove style overflow.

Yes, can't find the thread and I think it was back mounted overflow.
I would do a wire down each side then razor across the bottom. Be sure not to slip into the corners of the walls.
I wonder if you cut most of the plastic out then twist the piece connected to the corner, and with help of a razor, get that little section out. Just go slow and steady.
Definatly use glass to cover the holes on the inside.
Good luck!

Tonycass12 · Nov 30, 2022

Dburr1014 said:
Yes, can't find the thread and I think it was back mounted overflow.
I would do a wire down each side then razor across the bottom. Be sure not to slip into the corners of the walls.
I wonder if you cut most of the plastic out then twist the piece connected to the corner, and with help of a razor, get that little section out. Just go slow and steady.
Definatly use glass to cover the holes on the inside.
Good luck!

Thats what I'm thinking I may just use a dremmel and remove all the plastic and notch the bottom corners very close to the glass but with some room around the silicone to keep it from being disturbed. That way I can break or cut the remaining plastic from the overflow away from them and leave a small chunk that will be below the sand eventually. Thats the only way I can see of doing it and not messing up that silicone where the sides and the bottom glass come togeather.

Tonycass12 · Nov 30, 2022

Re thinking things now. Was getting the tank cleaned up after work today and noticed this ugly sticker. Im going to assume that all the sides are tempered but I'm unsure about the bottom. So that leaves me with 3 options.

1. I leave the tank as is and just make due with what I have and upgrade to a peninsula in another year or two. This is obviously the least amount of work.

2. Remove the overflows as planned and add an overflow to the center of a short side. The bottom should be able to be drilled so moving the holes shouldn't be a big problem. Probably the most work of any of my options.

3. Remove the overflow on one end and keep the other. Would have a little section I would have to cover to conceal the view of the inside of the remaining overflow but not really a big deal. Plumbing would end up coming over the side for the returns.

At least the tank is all cleaned up the glass had a good coating of algae and coralline build up.

Tonycass12 · Dec 10, 2022

Went ahead and pulled the overflow from one end. Everything was pretty easy these were only held in with silicone so it pulled right out after a couple passes with a razor blade. Now I just need to find a local shop to cut me a chunk of glass for that corner.