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DIY Sump for 90 Gallon Aquarium
DIY Sump for 90 Gallon Aquarium

I built a DIY sump filter for my 90 gallon freshwater aquarium using a standard Aqueon 20 long tank. There are a lot of great advantages to using a sump filter, especially on larger systems. A sump can hold several times more filter media than a hang on back or canister filter. Sumps also allow you to remove equipment, like heaters, from the display tank so that it is out of sight. Finally, since a sump can technically be any container that holds water, there is a lot of room for customization.

Overflow Plumbing

Gluing the Overflow Plumbing
Gluing the Overflow Plumbing

This system is using an Eshopps Eclipse (Medium) overflow, which requires drilling a hole for a 1.5" bulkhead. The overflow has two 1 inch bulkheads, which allows for a Herbie style overflow setup. With this configuration, the primary overflow valve is set partially closed, so that the water level in the overflow box rises to the top of the red secondary, or emergency, standpipe.

Herbie Drain
Herbie Drain

The partially closed ball valve limits the flow through the strainer, maintaining a siphon that runs quietly. A small amount of water flows down the open emergency standpipe. This configuration is popular in reef tanks for its quiet operation and ability to handle a lot of flow without worrying about a clogged strainer causing the display tank to overfill.

Sump Design

This sump is built from a standard size Aqueon 20-long, with three glass baffles siliconed in place to create the different sections. The first two baffles force water flowing into the sump down through the mechanical media and then up into the second section. The third baffle sets the minimum water level in the sump at about 6", or half the height of the tank. This leaves room for roughly 9 gallons of water to overflow from the display tank into the sump in the event of a power failure or pump failure.

Empty 20 Gallon Sump
Empty 20 Gallon Sump

Egg crate style lighting diffuser creates dividers that hold the media in place and keep it off the heaters. I cut sections of the lighting diffuser down using wire snips, and attached the pieces to each other with zip ties. The first section has a platform that holds the media up above the bottom of the first baffle.

Lighting Diffuser Platform
Lighting Diffuser Platform

The second section of the sump holds the bio media and heaters. Here I made a platform for the media to sit on, as well as a divider for the heaters. I also made an air driven circulation device using an old sponge filter housing without the sponges. The two intake tubes sit on the glass bottom of the sump below the diffuser, pulling water from the bottom up to the top of the media. The idea was to create more movement across the media and oxygenate the water before it gets returned to the aquarium.

Circulation Lift Tube Installed
Circulation Lift Tube Installed

Filtration Media

This sump is using a combination of polyester quilt batting, thick sponges, bio rings, and lava rock for filtration. Water flows from the overflow pipes into a basket that holds a layer of polyester batting, which catches most debris and fine particles before they get into the rest of the sump. I covered how cheap and awesome quilt batting is as a filter media in my post about DIY filter hacks.

Polyester Batting
Polyester Batting

The bottom of the filter basket is lined with a 1 inch think coarse sponge. This traps debris the batting didn't catch and allows the water to drain evenly through the sides and bottom into the 3 inch layer of sponges below.

Mechanical Filtration Basket
Mechanical Filtration Basket

In the second chamber is 7 pounds of lava rock, with 4 one-pound bags of bio rings on top. Lava rock is highly porous and often used in pond filters because it is cheap to buy in bulk. I picked up a 7 lb bag for less than $10 at a home improvement store. I got the bags of bio rings, as well as the coarse sponge for the filter basket, from aquariumcoop.com.

Biological Filtration
Biological Filtration

The heaters are positioned in front of the bio media so they are easily visible and accessible if I need to make an adjustment. The final chamber houses the pump, which sends the water back up to the display. This section has extra space I can use to add activated carbon, purigen, or any extra media I may want to cycle.

DIY Sump in Service
DIY Sump in Service

The entire build for this DIY sump cost me under $100, not including the submersible pump ($20) and overflow ($110). Compare that to canister filters like the Fluval FX4 that, while effective, run well over $250 and provide virtually none of the advantages of a DIY sump.


4

My 90 gallon freshwater aquarium is filtered by a sump made from a 20 gallon long tank. Details on that build will be posted soon. I bought the tank second hand and it came with an Eshopps hang on back overflow, but I decided to drill it after doing a lot of research about different plumbing options. I don't want to have to worry about losing siphon in a HOB overflow, and the Eshopps Eclipse overflow box I chose takes up less space inside the tank and looks cleaner.

Eclipse overflow installed
Eclipse overflow installed

I bought this aquarium used, so I was not sure what brand it was, but based on the dimensions and the design I believe its a standard Aqueon 90 gallon. This is important to know so that you can determine whether or not the glass is tempered. Aqueon has a great reference sheet that lists the dimensions of all of their tanks and whether they have tempered bottoms. I still checked the sides of the tank with polarized glasses and a cellphone in sunlight to make sure they were not tempered.

Drilling the Tank

The Eshopps Eclipse overflow comes with an included drilling template and diamond coated hole saw. This helped tremendously because it eliminated the need for me to measure and mark where I wanted to drill. I also didn't have to make my own template to get the hole started. The template is a piece of acrylic with a hole sized for a 1.5" bulkhead.

Eclipse Hole Saw and Template
Eclipse Hole Saw and Template
60mm diamond hole saw
60mm diamond hole saw

To drill the hole I clamped the template onto the inside of the back wall of the tank. With this kit, its important to push the top of the template up to the inside rim of the tank so that the water level isn't set too low. I didn't want to lay such a large aquarium on its side, so I drilled the hole with it upright. I clamped a hose onto the rim of the tank to keep a stream of water on the drill bit.

Eshopps Eclipse Hole Saw Template
Eshopps Eclipse Hole Saw Template

The actual drilling was similar to what I covered in my post about drilling 10 gallon aquariums. It took about 15 minutes to drill all the way through the glass. The side of a 90 gallon tank is about 3/8" thick, and I didn't want to go too fast and crack it. I ended up with a nice clean hole for the overflow bulkhead.

Drilled Hole for Overflow Bulkhead
Drilled Hole for Overflow Bulkhead
Glass removed by the hole saw
Glass removed by the hole saw

I decided not to drill the tank for a return - because I will probably want to make a spray bar or play around with different returns - so this was the only hole I had to make. Having a drilled overflow makes me feel a lot better about the risk of the tank overflowing. Below is a shot of the overflow box on the back of the tank. I'll go into more detail on the plumbing and filtration for this aquarium in a later update.

Eclipse Overflow Box Installed
Eclipse Overflow Box Installed


19

20 long with DIY glass lid
20 long with DIY glass lid

I have DIY glass aquariums lids on three of my planted tanks. They're cheaper to make than almost any lid you can buy commercially and, unlike lids with hinges, they allow a ton of light into the tank.

Each one of these lids cost less than $20 and required no tools to make

Pros & Cons to a DIY Glass Aquarium Lid

Above you can see a glass lid on my 20 gallon long planted tank. There are a lot of benefits to a solid glass lid like this:

  • It wont become cloudy or discolored over time like plastic lids
  • It wont bend or sag like plastic lids
  • It keeps moisture in the aquarium, and blocks almost no light
  • It is made custom for your application, so you can choose its dimensions

There are only a couple of reasons NOT to use a solid glass lid:

  • This design only works on aquariums with a rim on the top
  • They are breakable, and can cause injury to you or your fish if broken (I have broken one)

In my opinion the benefits definitely outweigh the risks. I have used these lids for years on different aquariums and only ever broken one. No glass actually got into my aquarium, I was moving the lid and not paying enough attention. If you're always careful when handling them, there's not much to worry about.

How to Make a DIY Glass Aquarium Lid

Making one of these lids is very simple. All you need to do is:

1. Measure your aquarium

You want the lid to rest on the ledge inside the plastic rim of the tank, so you'll measure from one inside edge to the other. Then, you have to decide how far across the aquarium you want the lid to extend.

measure top of aquarium
measure top of aquarium

In the photo above you can see my HOB filters extend about 2 inches into the aquarium. I had my lid cut to leave a little more than 2 inches of open space in the back, so that the filters don't contact or spray water onto the glass. This space on the back side is also handy for dropping food into the tank without moving the lid.

2. Have a piece of glass cut to your dimensions

I have always gone to a local hardware store to have pieces of glass cut, but you can also go to a specialty glass shop. I use Ace Hardware in the Denver area, but I have also heard that some Lowes locations will cut glass. You should be able to find a place that will cut glass in your area.

Since this is just a single pane of glass, it should be less than $20, even for a long cut like my 29" lid below. I paid about $10 for that piece of glass that is roughly 29" x 9".

this lid is 29" long
this lid is 29" long

3. Attach hooks for lifting and moving the lid

I use clear command mini hooks as handles for these lids. A pack of these hooks is enough for 4-5 DIY aquarium lids, and only adds a couple dollars to the cost of each one.

clear hooks
clear hooks

I like these because they blend in with the glass lid, and they stick on extremely well. Once they are attached, you can lift the lid off just using the two hooks as handles.

That's it. These lids are easy to clean using a damp paper towel, and the only maintenance they require is being wiped down once every month or so. As long as you're careful not to drop them, they will last as long as your aquarium.

glass lids on my two 10 gallon tanks
glass lids on my two 10 gallon tanks

If you are interested in other types of DIY aquarium lids, see my post on making lids out of Polycarbonate here.