Underwater Waterfall, for Cheap!




About: I've been coming to Instructables for years, but I only recently made an account. I love to build things, especially Aquariums. I love living things, and helping things come to life.

A feat so amazing you would think it's impossible. Even more amazing, it's easy and cheap. This gorgeous waterfall actually isn't water at all, it's sand. Using the same principles of physics that make bubble filters and Alex Andon's Desktop Jellyfish Tank work, this feature uses air bubbles to push water up a pipe to the top of the aquarium, creating a sort of vacuum to carry sand up to the top.

This project will only take a few hours to put together (depending on how much experimenting you do) and most aquarium hobbyists will have some of the parts lying around. I completed this project for under $50.

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Step 1: Materials


A tank (obviously) Under $20 at thrift stores.

Length of 1" PVC pipe about the height of your tank. ~$4

2 elbow joints ~$2

An air pump (I used a Whisper 60 for this 10 gallon tank) $30

Air tubing ~$2

1 air stone ~$2

A bag of sand (A fine grain, but too fine and it will cloud your tank. I got mine from Fred Meyer. White looks the most like water) ~$5

Rocks for a natural look Free- $20

A plastic water catcher tray ~$2




Step 2: Assemble the Pump

First, cut your PVC pipe to length, about 3 inches shorter than the height of your tank to allow room for the elbows. For my standard 10 gallon tank, this was about 8 1/4" (21 cm).

Now drill a hole in the top of one of the elbows, the size of the air tube. Then thread the tubing into it. This will be the top of the pump. Fit this onto the pipe, making sure that the air tube goes all the way through to the other end.

Attach the air stone to the end of the tubing, and fit the other elbow onto this end. The air stone should be at the bottom of the pipe (see pictures for details).

This is now a completed pump. Just attach the air tube to your air pump and submerge it underwater, so that the top half of the top elbow is out of the water. You should see that the water starts to flow.

UPDATE: The current may cause sand to shoot out of the pipe and spread throughout your tank. To fix this, I took a piece of fiberglass mesh screen, and glued it around the opening of the pipe so that it makes a U shape in front of the pipe. This blocks the sand very well. I used just a dab of aquarium grade silicone on either side of the pipe and wrapped a strip of the mesh around it. Sorry if this sounds confusing, see the last two pictures for better detail.

Step 3: Collection Basin

The sand has to go somewhere, and there are many ways you could do this, but here is my solution.

Cut about a third of the water tray around the edge (if you're putting the waterfall in the middle of the tank, cut it in half), leaving about 2 inches of plastic around the base. Place this in the corner of the tank as shown in picture 2. Now place rocks around the edge to hold it in place as shown in picture 3.

Now you have a nice place for the sand to gather to be collected again by the pump.

Place the pump in the corner and fill the area with sand (Pic 3 and 4).

This is when I took the time to fill the aquarium to test it out (Pic 5).

Step 4: Stacking Rocks

I placed a couple of small river rocks in the sand on either side of the pump to provide a stable base to start stacking rocks on. The rocks I used was some basalt I had lying around. Whatever you can get your hands on should work, so long as they're somewhat square. Stack them all the way up to the outtake.

Sorry I don't have any pics of me doing this. But you're very clever. You can do this.

Step 5: Decorate!

Add some gravel to the rest of the tank. I chose to go with brown pea gravel, but anything will do. Make sure to make it deep enough to cover the plastic tray. Or don't. Aquariums are art, so you may do whatever your heart desires with yours.

I put some Java Fern in between the rocks as you can see in the picture, and on the other side of the tank I banked up the gravel and put in a few more pieces of basalt, as you can see in the video in step 1. Other plants I used are Staurogyne Repens, Water Wisteria, Amazon Sword, Willow Moss, and Cyprus Helferi.

That's it. You're done.

Step 6: Tips and Tricks

Check out the pictures above for inspiration

Also check out these videos:

Some additional things you might try:

You might be able to hide your heater and filter behind the rocks if they are small enough.

Create a custom rockscape for your waterfall to flow over using methods from these Instructables.



White sand looks the most natural, but you might also use colored sand for a visually striking waterfall. Florescent sand under a blacklight light can make your waterfall GLOW!


Use another pipe to make a wider fall (Pic 4).

Try using an elbow with a wider mouth at the bottom for increased flow.

If you liked this project, please vote for it in the Aquarium Contest.

Age of Aquariums Contest

First Prize in the
Age of Aquariums Contest



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40 Discussions

I won First Prize in the Age of Aquariums Contest! Thank you so much to everyone who voted, and to the judges.

Also, just hit over 30,000 view! I had no idea this instructable would be so popular. Thanks everyone!

If anyone tries this project, PLEASE post a picture, or a video, or an instructable. I really want to see what people do with this.

I'm especially interested in trying it in saltwater tanks. I have no experience with saltwater, so if anyone has any information on this, it would be much appreciated.


4 years ago

That is very cool! Nicely written. Do you think this is possible in a salt water tank?

1 reply

Reply 4 years ago on Introduction

I was wondering about that, and I'm not sure. Just to be clear, I have zero experience with saltwater tank, although I've done a lot of research on them.

That being said, I see no reason that it wouldn't work, and if you, or anyone else, tries it, I'd love to see a picture. Or preferably a video.


4 years ago on Introduction

So, is this something that could be done in a tank with fish, or would it be somehow problematic to have sand floating in the water with them? I feel like it should be fine, given all the sand in the ocean, but I know how sand feels in my eye, so I can't imagine it feels good in gills...

1 reply

Reply 4 years ago on Introduction

The sand is perfectly safe for fish, and inverts. Water flows out of fish's gills, so I think they would be able to easily dislodge a small piece of sand if it did get in their gills. Even so, fish are smarter than people give them credit for. They should be absolutely fine.


4 years ago

Hi there. Hopefully you can still help me out and check this .My waterfall worked fine, and then suddenly stopped. It seems like it doesn't have the suction power, like sand is being pulled into the pipe but not all the way up. Any suggestions? Thanks!


4 years ago on Introduction

Great Job want to know how does the sand flow to the collection area and a video of stone stack will be helpfull to understand


4 years ago on Introduction

This is fantastic but please don't claim ownership of this idea as you are not the original creator of the idea and methods of making it(I don't think you did but im just sayin :) )

4 replies

I do not claim ownership of this idea in any way. I am the first person to make an instructable about it though.

As you can see, in the last step I did include pictures and videos of people's work who have done this before me and inspired me to do this project.

Thanks for your compliment.

How strong of a stream of air are you putting in the airline tubing for the air stone as I've built several sand falls and my problem seems to always be not enough air to push the sand up or too much air causing my sand to blow all over the aquarium ? I have a 46g Marineland Bow Front Aquarium with 4 Parrot Fish basically have a small cave and a bought piece of deco art from Petsmart any help would be greatly appreciated as I have a sand fall ready to install it's made up of slate tile and marble putting coral and shells in between the slates looks pretty good so far tested and air comes out of the top elbow and also I've found that if you drill a 1/8" to 1/4" extra in the top elbow it seems to draw the sand up better just a thought Thanks Mike

2 replies

I'm using a Tetra Whisper 60 to move the sand only about 10 inches, and I restricted the pump just a little bit. I was thinking that having a larger opening at the bottom than at the top could accelerate the flow a bit, but I'm not certain of that.

As for sand blowing through the aquarium, I can help with that. I glued a piece of fiberglass mesh screen in a U shape in front of the pipe. I've been meaning to add that to my instructable, I'll do that within the next few days. I just put a bit of aquarium grade silicone on either side of the pipe and wrapped the mesh over it, using a strip long enough that there was about an inch of space in front of the opening of the pipe. Sorry, it's hard to describe, I'll post pictures.