So I had an E02 failure in my egg-shaped AirJet pump. I changed the propeller, but I was not able to test if the E02 is gone, as the pump basically expects to have proper level of water inside. On the other hand, I wanted to descale it just for peace of mind, so I quickly designed a small water reservoir connected directly to the pump.

This was done in Tinkercad and is far from perfect, but it works great.

Distance between inlet and outlet is 15.5cm (measured from center of inlet and outlet), but keep in mind that these pipes are quite flexible, so some wiggle room is avaliable if your pumps differ somehow.

Water reservoir is 7x7x25cm (not including threads).

There is an extra cover that you should print as there is a lot of water splashing around.

There is HUGE room for improvement:

• Reservoir could have rounded edges and the bottom is too high (I was too lazy to fix this).
• There could be some water release system added to the bottom.
• Cover should have better mounting system (but this one works)
• BUT keeping in mind above: this gets the job done, so while it was designed in 10 minutes and printed overnight, it is good enough for me.

Print with supports and 4-5 walls for strength. PET-G is a good choice.

I used awesome screw design from Eried: https://makerworld.com/en/models/462546