My Custom Sump

Okay so I'm hoping at this point you're following along. I've explained the basics of a sump and now it's time to GET a sump. Most of you are probably thinking "cool, lets go to the fish store and buy one." Sure you can do that. Maybe. Sumps are made in certain sizes and shape to fit under certain aquariums. They are also fairly expensive. You could custom order one and it'd cost a few hundred followed by a few hundred more to ship it. I decided to take a different route. I've decided to build my own sump!

Okay so you may be thinking yeah right good luck. Am I the handiest man in the world? No. Have I ever done anything like this before? No. But still, I have a lot of free time and I want to try my hand at it, so cut me some slack! I mean hell, I know more about it that you do, boob.

So remember back a few posts ago I said...

"Well there are a couple different parts that come together to make a successful tank...

1- the tank
2- filtration
3- lighting
4- water chemistry
5- decor
6- fish!"

...well now it's time to focus on #1 the tank. Most all tanks are made of glass. They're more abundant and cheaper typically. But there is another options it's called acrylic. Acrylic is a type of plastic so it has very different properties than glass. For starters is MUCH stronger. Like 20 times stronger than glass. A good quality to have in a tank I'd say. It's also lighter which is good for handling and movement. On the downside acrylic is very prone to scratching. In fact, most anything will scratch acrylic whereas glass is very hard and resistant. Then again you wont have to see my sump the whole time so a few scratches won't make a big difference. Acrylic is also easier to cut- you can just use a table saw and chop it up yourself. I'm not sure how to cut glass but I really don't want to mess around trying to do it. For all these reasons I've decided to build my sump out of acrylic.

Another thing to keep in mind is a sump should take as the maximum space possible. You see, with a fish tank the more water the better. More water = more space for your pollutants to be diluted in and therefore are less likely to kill your fish. I'm going on the principle more is better and will make my sump the maximum size. So lets see how big I can make this thing..

So first problem. Remember my tank? It's a weird shaped pentagon. So in order to use the maximum volume I need to make an odd shaped tank. A rectangle just won't use sufficient volume. Here's a view of the interior of my stand to give you an idea. So I decided to go with an "L" shaped sump that will fit underneath my stand with a length and width of 15'' of the two long axis. Keep in mind my tank is TALL so if I want to use maximal volume I need to build my sump up, not long. Most sumps are just typical short rectangles. So far I've decided to build a 15x15 "L" shaped tall sump. Straight off the bat this is a weird project. I measured out my maximal height space and I have 22'' to work with upward. So I've decided to build my sump 16'' tall So I have a few inches to reach my hand in and work on the sump if I so need. So far sounds like an okay plan, right? Here's a schematic.

Below-tank sump schematic (click for larger view)

So as you can see nothing too complex. In theory. Now the only issue is I have no measuring instruments, no acrylic, and no table saw to cut it with, and nothing to glue to together with! First thing first I checked the local yellow pages under "plastic" and found an acrylic supplier. Took a trip to the store and bought about 40$ worth of 3/16'' thick acrylic. That wasn't too bad. A quick look on craigslist yielded me a small table saw for 40$ as well! After an afternoon of putting the saw together and doing some research online I learned I was going to need a blade with approximate 80 teeth on it. My current blade only had about 40. Supposedly too few teeth and the cut won't be fine and clean enough to weld properly in the end. A trip to the hardware store and another 40$ and I had a new blade. Somehow I even figured out how to install it. Certainly not professional work but it'll do the trick. Oh and don't worry- I eventually got the blade's guard to stay on.

Not gunna lie, I was a bit terrified the first time I used the saw. I had to assemble it myself and change the blade and I figured if I did anything wrong this blade was going to fly out at me and slice me with like 10000 rpm's of evil. At least it'd be a quick death. But no issues. The acrylic was easy to cut and the blade worked fine. The biggest issue was I was covered in plastic shards at the end and my neighbors probably didn't appreciate the noise (boo hoo).

I sliced up all my pieces and I was ready to begin forming the sump! Here's something I didn't know about acrylic until I started working with it. You don't actually glue acrylic together, you weld it. You use a plastic adhesive (its the consistency of water) and apply it between the two pieces. The liquid actually "melts" the two pieces of plastic together on a molecular level so it's more like welding than gluing. Here's a fun video (Tap. Tap plastics!) on how to properly weld acrylic. Sadly I didn't find this video until 1/2 way through my sump. Oh, and for any of you who might actually care about the specifics, the guys at the plastics store told me to use Weldon #3. So that's the solvent I used.

So I welded the box! I must admit I didn't really have all the tools and that's kinda a bummer. I didn't have a T-square or really anything to lean my pieces against to ensure they were at 90 degree angles so for anyone who's going to try something like this ensure you can do perfect right angles! The seams were far from perfect and I had some blotches (if the solvent drips anywhere it leaves a stain) but theoretically it is a functional sump. Take a look!

Ain't she pretty?

After about 10-30 minutes the tank is solid but it is highly recommended you let the solvent cure and the joints to weld for at minimum 24 hours. Many people give weeks to months to allow for a strong seal before using in an aquarium.

So that was day 1! Not too bad over all had a lot to learn and was some good practice!

Day 1
Cost- 40$ materials
80$ tools

Time- Approximately 6 hours