I took a look at the Innovatek blocks they look like they have a very small channel. I would go with changing out the tubing and go with 1/2 OD. If your lines are stiff, right now it is probably from too much backpressure. I recommend getting "quick connect fittings" like mine
You can get them at
US Plastics or at
McMaster-Carr.
Make sure you get the plastic compression fitting inserts.