How to Build A Sump

Updated: Sep 27


Custom built sump with protein skimmer and refugium

Building a sump is one of the best upgrades you can do to your BioCube. Yes, this means your BioCube is no longer an All-One-System, but the benefits of the sump are there whether you are running a nano tank or a 100 gallon system.


Benefits of A Sump


What's that benefit? More water = more stability! The smaller your water volume, the more susceptible it is to fluctuations. Think of it this way: Does a small increase in temperature cause natural reefs to instantly crash? No, of course not, because the ocean is a HUGE water volume. The more water you have the more tolerant your system will be. This small sump increased the water volume in my BioCube by 50%. Win!


Another great thing about sumps is that it provides a house for all your filtration. For a BioCube this is especially useful because there is not a lot of room to put some beneficial filtration in the back. Here, I put in a protein skimmer, a refugium, a ph and salinity probe, a GFO and Carbon reactor, and my heater. (Affiliate links to these products below; product reviews coming soon!)


The refugium is great. There are all sorts of debates on the best use for them. Technically, they are to provide a refuge for your more delicate creatures, like copepods, allowing the population to grow to help balance your ecosystem without getting eaten prematurely. But a popular use is the way I use it. Growing macro algae. See that big ball of green in the middle chamber? That baby is sucking up all the excess nutrients that would otherwise cause nuisance algae to grow in my display tank. I use Chaeto. Put a small light on it and it grows fast. Periodically take some chunks out and you instantly exported a whole lot of excess nutrients. Success! (If you want to pick up some Cheto, I offer it for sale with local pick up here in New Jersey. Check out my store!)


OK, Andy, You Convinced Me, How Do I Build A Sump?

Glad you asked! It's actually quite simple. So simple in fact, my 7 and 4 year old helped me do it! (It even inspired them to get their own aquarium!)


Here are some videos showing you how to build a sump!








Affiliate Links

Here's a list of what I used to make the sump and what I put in it. I hope to do product reviews soon, but in short, I'm only including links to the stuff I like and think works great, especially for the price. I'm not including anything I returned or threw out.




  1. Aquarium Silicone

  2. Aquamaxx Protein Skimmer--this thing is great! It is really plug-and-play, no need to figure out how to set up. And great customer service. I had some questions and they provided answers right away!

  3. Filter Socks with Draw Strings--I had to look around for these. I needed something small enough to fit in my sump. Most have a 4 inch diameter to feed the hose into. That would have left no room for my skimmer. These are both smaller and have draw strings to I can just tie it around my drain pipe. Throw in a bag of ChemiPure Blue and I ensure all water is flowing through my chemical filtration!

  4. Kedsum Pumps--These things are cheap and silent. At first, I just put my MaxiJet 1200 from the display in the sump, but it sounded like an earthquake. These are silent and powerful.

  5. Two Little Fishes Phosban 150.

  6. Auto Aqua Automatic Water Change--This is A-M-A-Z-I-N-G and will be featured in Part 2 of my Water Changes Made Simple series. It allows you to automatically change out a little bit of water every day so you new longer have spend time siphoning and dumping buckets. It also includes an automatic top off system.



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