Thank you for the kind compliment!
Yes, those are flow meters on each port of the manifold. They aren't a must-have, and if you do want to measure flow there are a couple different ways...
I find meters do come in particularly handy though for things like UV sterilizers, and carbon/gfo reactors however.
For meters, you also have the ones that go with the Neptune Apex. I picked the ones I used for reliability, and I think they look cooler [emoji41].
Let me know what your thinking, and I'm happy to draw you up a design, and give you a list of materials. There are a lot of options, so we can go all out, or make it budget friendly. Just let me know when you're ready!