How To Plug A Drilled Aquarium: 2 Easy Methods!

How To Plug A Drilled Aquarium

Aquariums need to be drilled because of built-in overflow. The drilled holes can be in the bottom or in the upper left corner. Depending on the overflow holes are drilled in the rear or bottom parts of the tanks.

But you might not need the holes and want to plug the holes. 

So, how to plug a drilled aquarium?

For plugging a drilled aquarium, you need to patch a glass on the hole. For this, you need a piece of glass and aquarium silicon. Simply apply silicon to the glass and patch it on the hole. After that, you can install a bulkhead in the hole. Another method is to use a rubber expansion plug.

This is not all. We’ve discussed the methods broadly in this article. To know the methods in detail read the article till the end.

How To Plug A Drilled Aquarium

How To Plug A Drilled Aquarium: Step By Step Guide

Method 1: Glass Patch

Things you’re going to need 

  • A piece of glass (same thickness as aquarium glass)
  • Aquarium-safe silicon (To cover up the bottom drilled hole)
  • And a glass cleaner to clean the glass. 

First, clean up the drilled space a little bit. The bottom drill hole is actually a nice feature if you want to use it. But sometimes it is tough to maintain if you have limited space and time. 

The glass needs to be approximately the same thickness as the aquarium itself. Otherwise, for pressure and playing with rock and other stuff, it doesn’t feel secure. So that nothing can happen for which you really need a thick glass. 

Next what you are going to need is aquarium silicon. It is essential to use aquarium-type silicon if you ever glue anything inside the aquarium. Because the whole thing is going to be under the substrate. It doesn’t matter if it is black, white, or transparent.

Some intend to use flex glue to seal their aquarium. But make sure that the flex glue adhesive you’re using is dry and cured.

Now, open up the surface of the aquarium and clean up everything. Use a glass cleaner that can remove oil and fat from the glass surface inside the aquarium. Also, clean up the piece of glass. 

After cleaning up the glass, apply the silicon around in a round shape on the glass. And then simply insert the piece of glass inside the aquarium.  Now, place the glass on the drilled space and gently press it to adjust the glass. Leave the glass for 24 to 48 hours to dry.

Method 2: Installing a Bulkhead

Things you need for the installation are a paper towel and water. But you can use an alcohol pad. It will make quick work of any dirt and debris and remove oils from the surface. 

First, clean the inside and the outside of the glass. While the glass dries, you can clean the bulkhead flange on both sides of the rubber gasket. 

Now, the main focus is to clean all the surfaces that will create inside the tank. You can plug your bulkhead to properly create a seal that will remain leak free. 

Plugging the bulkhead with a gasket in the flange is also a good option. You can plug it on the inside or the outside of the tank. 

Although some reefers have created seals when installed backwards. This does leave a high risk of developing a leak down the road. 

Now, the hand tightens the retaining nut from the dry side. Make a small 8th through the quarter turn with a pair of pliers. One thing to mention here is usually hand tight is enough to create a seal. Also, over-tightening can crack the glass or bulkhead itself. 

You can tighten the retaining nut until you meet pressure, and then you can use the pliers. Also, the threading on the outside of the bulkhead is only there for the retaining nut. It will not adapt to standard plumbing with different threads. 

All you are left to do is fill your tank for a leak to test. You’re done if you do find a leaky bulkhead usually tightening the retaining nut. Another eighth of a turn can solve it. But again you really want to be careful not to over-tighten.

Method 3: Rubber Expansion Plug

Go to any hardware store and look in the plumbing department for a test plug. It has a plug with a rubber gasket around it and a wing nut on one side. They come in a variety of sizes. 

I have been using one on an acrylic aquarium for years with no leaks. It is easily removed with a turn of the nut.

You can use a rubber expansion plug for your aquarium too. The rubber expansion plug is easy to use. You can easily plug in or unplug it. 

Alternatives Of Plugging A Drilled Aquarium

You should use Weld-on acrylic cement to affix a larger piece of acrylic. It will cover the hole for a long-lasting repair. Purchase an acrylic piece that is at least 2″ bigger in all directions than the hole. But bigger would be preferable. 

To ensure a flat tank bottom, I would place it within the aquarium rather than underneath.

If you want to decorate your aquarium you can use clay pots. Attach the clay pot’s bottom with silicon. 



What Does It Mean When An Aquarium Is Drilled?

Reef-ready aquariums, also known as RR aquariums or RR tanks. It is built-in overflows in the middle or a corner of the rear glass. It has holes that are punched into them. The hole is drilled in the back or bottom panes of the tank in the factory. It actually depends on the type of overflow.

How Thick Does Glass Need To Be For An Aquarium?

The typical size that most enthusiasts are familiar with is the 4-foot by 15-inch, 55-gallon aquarium. Glass measuring six millimetres (or 1/4 inch) thick is typically used to build this aquarium. The glass has a safety factor of 2.92, per calculations according to the aquarium glass thickness chart.

What Type Of Glass Is Best For Aquariums? 

Compared to glass, acrylic is substantially lighter. A material that can provide you with at least 50% the weight of glass. And still keeping strength and integrity is undoubtedly an enticing alternative as aquariums get bigger. Glass of the same dimension is about 17 times stronger than acrylic.

Does Drilling A Tank Weaken It?

Yes, drilling a tank has an effect on its structural integrity. But the outcome of the drilling won’t be enough to cause problems. Unless you go crazy with the quantity or positioning of the holes. The vast majority of tanks are built with a respectable level of structural latitude.

Can You Drill Tempered Glass Aquarium?

No, you can’t. If you try to drill tempered glass the glass may shatter. Many manufacturers add on their aquariums not to drill a tempered glass aquarium. It is better not to mess with your tempered glass aquarium.


So, that’s all about how to plug a drilled aquarium. Follow the methods to plug your tanks. 

Hope the above-mentioned method work for you. The opportunity to create, construct, and personalize our tanks is what I love most about aquariums. Keep up your aquarium hobby.

That’s all from my side. Hope to see you in the next article.

Until then take care!