Complexity of design about akvo-caddisfly-colorimetry-hardware HOT 2 OPEN

Update #1 at resolving this:
3 pieces, the main body, a lens and a cap (not added in the prototype). No need for a mesh/additional components - Easy to manufacture and assemble
rectangular footprint- keeping in mind the need for an increased diameter to accommodate the flash in most phones
Problems:
Volume has increased. Now about 10ml.
No overflow chamber, but it can be accommodated on top of the testing chamber.

How it looks on the phone:

from akvo-caddisfly-colorimetry-hardware.

Update 2:
Similar to previous design, but circular shape with threading so it can easily be integrated with the current versions. Did a calibration + test, didn't look too promising.
Fixed the increased volume of the previous iteration. Now 6ml.
Problems:
Had to reduce the height to accommodate the same volume of water+camera flashes on all phones. Has lead to a much less saturated colour - more prone to errors.

from akvo-caddisfly-colorimetry-hardware.