This is my enhanced version of the Aquarium Overflow Box by MrLunk.

Changed:

• better flow rate
• added a connector to attach a 22mm hose to the outlet. No need to glue or stick in a hose into the hole in the model which would never be really watertight
• corrected errors in the original that can cause failed prints or water leakage
• added a fish weir on the intake so you dont have to fear that your little friends escape through the hose :)

General Notes:

This overflow box works on a physics principle. To make it work, you need to put it underwater and rotate it underwater a little, so ALL air is coming out. It needs to be filled totally before you can slide it onto your fish tank. But then its working perfect. It will always transport the amount of water that is reaching the surface of its intake out of the aquarium.

This is perfect in case you have a pump that is pumping up water into your aquarium and you do not want the additional water to fill up the aquarium and run over its edges.

If you have some little aquarium under your fish tank where you put in all your technical filtering stuff, you can create a wonderful cycle of filtered water being pumped up into your fish tank and exceeding water running down into your filter aquarium.

Prusa

i3 MK3 MMU 2

No

Yes

0.1

100%

I recommend transparent PETG since it´s foodsafe.

Also make sure your print settings are optimized for a watertight print.
For me it worked with 100 % infill, 6 perimeters and 9 top and bottom solid layers.

The print takes a good while and make sure to pause and clean your nozzle with a brass brush every now and then in case you experience burnt filament flakes being baked into the print.

Also try to print with supports but put a support blocker between the two separate large blocks (the intake with the fishweir and the outside box with the outlet) so it does not print supports from top down all the way to the connecting tunnel on the upper side. It does not need supports there. The overhang can easily be printed without supports.

HOWEVER it probably NEEDS supports on the hose connector.

So you may try what is working best for you. I added supports under the hose connector and blocked them everywhere else. Make sure you dont have any supports inside the model as you will never be able to remove them later (unless you use water soluble support material - which is not a good idea for a model that is supposed to be watertight in total. Because you always have some smaller amounts of the water soluble filament bleeding into your main print and when you put it in the water you get away the supports but your model becomes untight and acts like a sponge :) So i cannot recommend water soluble supports.