Well recently i just wanted to make a new fry saver by myself to waste time and to provide some more frysavers for my cory fry and bn fry. and after much thought and planning, here is how it ended up.
I just got a 4litre container and then cut out one end of it, and put in one of those carbon holding bags to cover it up to provide water from main tank
Next thing i did was punch two holes at the bottom to allowe me to attach a sponge filter (airdriven) with suction cups to provide some form of filtration and some water circulation
Before

During



After

technically i'm still not done with it because i plan to either silicon the filter to fry saver or using fishing wire just in case i want to take the filter off.
in the end it's a very simple model
All up it only took about 1 hour to make
Thanks
DJ