[Khledar]

Ok I gots an idea, that's some small ass tubing - could be putting a lot of strain on the pump. Since you're probably running the blocks in a series, why not try making a manifold to convert one 1/2"ID into two or three (or four!) 1/4" ID tubes and run all the devices in parallel.

Let's see
1/4" ID = pi*r^2 = 3.14*.125 ^2 =~ 0.0491

1/2" ID = 3.14*.25^2 =~ .196

.196 / .0491 = almost 4 (3.99something)

So if my math and reasoning are correct, which they probably are not, you could most efficiently run one 1/2" ID tube into a manifold, and four 1/4" tubes out. Not really sure what all the effects of this are and whatnot but someone's probably tried this so give us your insight!

GL
(AHHH! Edits all over the place except not in the math so it's probably still messed up.