good job, but I do notice one rather large design flaw;
you have all the water traveling over the top of all the media chambers and not
through the media.
You need to set-up the baffles so that water enters from the tank at the top and out the bottom of the first baffle, and then basically up/down through the rest of the chambers.
It appears as if the water simply flows over the top of everything.
You will not achieve very efficient filtration that way.
Luckily with silicone you can cut out a couple of baffles and re-seal them in new positions.
Take the first baffle and raise it up almost to the top so water exits it from the bottom, then add another small baffle to the top of the last (#3) baffle so that it creates a passage in the middle of the baffle for water to exit.
that way it will be forced to flow through the macro-algae without disrupting the sand bed of that section.
plus shouldn't you have the filter pad before the bio-balls? otherwise the bio-balls will become clogged with muck and lose efficiency.
Also lose the output pipe and let it discharge straight from the pump. That way you are circulating more of the tank. Where the discharge is now you are essentially re-cycling a lot of the same water through the filter and not moving the entire volume of water.
Remember, the intake and discharge should always be at opposite ends whenever possible.
