Wow!!! This is an awesome build. Love all the equipments you choose, no expense spared. One note though, not sure if you plan any manifold for the plumbing, but your return pump is most likely not strong enough for a 300g tank. Looking at the height, your return is probably going to give you no more than 800gph for just plumbing as a return. It's a fantastic pump but the flow probably not what you would expect after the height. Max gph of 1400 ish is at 0 height I believe, and at 6 feet ish, it going to drop a lot. With your budget I would look into a red dragon return pump . Good luck with your build.