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Discussion Starter · #1 ·
I am writing this post because I drilled my oceanic biocube 29 / BC29 it broke in the process and this thread may help someone in the future.
It's possible this thread also applies to other biocubes and specifically the oceanic series.

1. New back glass ($18)
19 3/4" x 15 3/8" (oceanic Biocube 29)
3/16" thick (though I must admit there's room for 1/4" glass
(Acrylic won't due because it doesn't stick well to silicone and I don't want to get into gluing 2 different materials.
Feel free to debate this in the comments)

2. A good flat scraping razor.
Exacto or box cutter could also be useful. But mostly for scraping off silicone

3. A 10 oz tube (caulk gun size) of aquarium safe 100% silicone sealant.
$18 (I overpaid)

4. Small flathead screwdrivers.
Good for getting silicone out of crevices


Step by step instructions.
I was inspired by another post on this and it helped me alot. So here you go.

1. Remove the top rim.
Stick your razor up underneath and carefully cut all the way around the tank until the top peels off.
if you do break it you only need the back corners for bracing. You can also modify it to go rimless if you choose, As long as you reinforce those back corners.
The oceanic biocube 29 "BC29" is glass all around, you probably won't scratch it. It's not acrylic.

2. Remove those plastic side things.
Take note of the tiny tab's on top of these... There are also more tab's on the bottom, be careful not to break them. I did, no big deal.
You remove them by carefully prying them off. Using the razor scraper as needed.

3. Take out the sump and divider
It's just siliconed in there. Just slice and scrape gently until it's out.
Taking it out makes the process so much easier.

4. Remove the back glass.
Once again it's siliconed in place. Gently slice and scrape until it's out.
Notably slice between the glass joints on all 3 sides.
It's harder in the bottom corners. If you got this far you know what I mean.

5. Scrape the silicone off the glass edges.
Scrape off all the silicone to clean up for reassembly.
It doesn't have to be perfect. Silicone sticks to silicone.

6. Order the glass.
You get this from a glass repair company. The kind that fixes house windows when you break them.

Measure it of you don't believe me.
3/16" thick
non-tempered (aka annealed) glass
Tempered is ok if you're not drilling
I also feel like 1/4" thick may also fit.

19 3/4" x 15 3/8
3/16" thick

Cost $18 (year 2021 "Rona era")

Your chance to drill is now while the glass is out. At your own risk.

7. Test fit the glass.
Make sure the bottom edge and corners are clear of debris that will prevent it from seating properly.
I used a tiny flathead to get the silicone in the bottom corners.

The top edges doesn't need to align perfectly with the other glass because the plastic rim covers these joints.

8. Clean up the plastic.
Get the silicone off it.
Alot easier than getting it off the glass.
A smaller screwdriver helps get the silicone out of the top rim.

9. Final clean before reassembly
Soap and water scrub the plastics.
Soap and water scrub the glass edges.
Clean the edges of the new glass.
Make sure everything is dry before proceeding.

10. Silicone. and back glass install
Gloves are recommended.
A large bead of silicone on the bottom, in the corners and up the display glass edges.
Carefully place the back glass and run finger up the excess silicone to smooth it out.
Make sure everything is watertight and beautiful.
You can move on to the next step or wait for this to dry first.
If you wait. Use duct tape to secure the 2 pieces of glass together.
Shims might work here too.

11. Silicone the inside corner of the side thingys and place them.
Be sure if you go crazy with the silicone to keep it out of the water level display window.
Use duct tape to secure the thingys.

12. Silicone inside the rim slot. Then install the rim.

Don't put the bead of silicone on the glass for the rim. Just put it inside the lip of the rim.
Press the rim on.

I light tap with a rubber hammer all the way around would be a nice touch, but I didn't think about it at the time.

Wait for it to cure for a day before ...

13. Water test.
Probably do this outside

13. Install black vinyl on back and cut the sump viewing window.
At your leisure you can get this stuff at Michael's, target or other crafting store.
I buy it by the roll on Amazon or eBay.

I hope this helped.

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