I know I'm coming into this conversation late, but I just came upon this thread and I have an idea for you.
Background: For the last year I was fighting an algae outbreak in my tank. I have a 110 gal
tank with sump, a Reef Octopus SRO 2000 (for up to a 500 gal
tank) and a reactor running phosguard. Nitrates and phosphates were all 0, yet I had algae. I tried everything to get rid of it, but in the end a large CUC of hermits has solved my problems. However, during this process, towards the end, someone mentioned an Algae Turf Scrubber (ATS) might be the way to go. So a few months ago I built an ATS and pulled both the skimmer and reactor out (along with their not so silent pumps). Low and behold, that was the start to my road to recovery. Even without the skimmer for a few months now, and increasing my feeding schedule (daily feeding now), my algae is almost completely gone, with the last few spots shrinking noticeably daily.
For what your pics show of your sump, you are perfectly set up for what I wish I would have done as I also have a 2 section sump. I would consider a weir type ATS setup. This would require very little to build in the sump you showed on the 25th.
You would need some 1/2" pvc
pipe, fittings, an acrylic rod and #7 plastic sewing mesh.
Using the fittings and pipe, you would build a few vertical pipes along the front and back glass, held apart by a couple pipes connecting the front and back rows.
The vertical pipes would have a slit cut on the inside right thru to the top of the pipe.
Then the mesh would be cut long enough to fit into the slit in a front and corresponding back pipe. a length of acrylic rod would be cut to the same height as the pipes and zip tied to either end of the mesh. The rods would slide down into the pipes with the mesh going out the slots.
Water in the sump would then flow through the mesh screens and with a light, algae would grow there. You would easily remove the screens on a 1 a week or 2 basis and scrape it clean. Your pods
would love it.
Best of all, I have only the return pump in my sump, no more noisy skimmer and reactor pumps to listen to.
I'll try to post a drawing of what I'm trying to describe.