A 3D model of an hydroponic tower that uses 3 inch cups, didn't test it too much.
Printed just one tower and gave it to a friend, if you have some feedback i will be happy to hear. 

I used petg with 0.6 nozzle. 

Link to the 3 inch cups :  https://s.click.aliexpress.com/e/_oFjodBp

Link to the pump i used : https://s.click.aliexpress.com/e/_oBv342b

You will also need  some tubing and a bucket. I bought those locally so there is no link. 

The top and bottom lid mounts are parametric models so you can adjust the outer ring size to fit better to your lid. You will have to put a 110mm hole in to the center of your lid. 

I also added a test you can print to the locking part. For me it fits very tightly.

You will need one of each part except the hydrophonic tower 3 way part which you will need one for each level you want. 

Good luck! 

Don't forget to upload your makes