Build Revision - Media plus DWC

I purchased a copy of the Green Acres Aquaponics' manual, which describes both the basic knowledge required for aquaponics and their specific build projects.  It was a good read.  I skipped a good deal of the basics, having already obtained them from multiple other sources.  But their build was fascinating.  They basically have a compact system that sports a small-ish fish tank (100 gallon I think), a roughly 4-ft by 4-ft media bed, and a 4-ft by 8-ft sump and DWC tank.  You can get all 8 feet of sump to work as DWC if you have the floor space available.

This turned me on to something I had been mulling over since I first designed my prototype: how to make use of that blasted sump.  One idea was to add media to it, to improve the bio-filter.  But without growing plants, it seemed like a bit of a waste.  The GAA manual also demonstrated how to use a specific liner for their builds, and that opened the door to this:

This is a media bed over a combination sump/DWC tank.  The upper bed is 2' by 8'.  The lower is 3' by 9'.  Since the entire system has to fit in a very small footprint on my back porch, and will already require artificial lighting, I'm planning on simply adding additional lighting to the underside of the media bed.   The last foot or so of the DWC will either get lighting somehow affixed over it, or be partitioned off and used as a place to add chems, etc.  While most publications seem to favor putting the pump in the sump tank, I still think I'd prefer it to be outside the tank for ease of access.  Guess we'll see how everything fits on the porch.

The GAA build also sported a radial flow clarifier.  The clarifier fed directly into the sump, and the media bed drained into the sump via bell-siphon.  I had originally started planning one into this build, but then changed my mind after figuring the media bed would probably provide sufficient filtration of the particulate matter.  That said, I can always add a clarifier later.  My idea for the clarifier was to set it high enough that I could set the sludge drain to empty into the media bed.  After all, the media bed was going to get straight fish water one way or another.  Theoretically, managing the plumbing such that the outlet for the clean water and the outlet for the sludge would be at the same elevation ought to give me two outlets with two different purposes, from the same device.  This will be something worth experimenting with in the future.

I have yet to price out the lumber for the above build, and the build requires a little further fine-tuning anyway.  If the total price comes out below the original build, I think that'll be a great value.  If higher, it will probably still be worth it for the fact that we'll more than double our growing capacity (since DWC gives you a much higher plant density than what you can achieve with media).  If significantly more - which I'd have a hard time believing - then we'll reassess just how important the DWC tank is.

Some things that this build doesn't give me: I won't be able to control the media bed flood and drain rates as much as if they were two separate beds - this means less opportunity for experimentation.  The DWC might suffer from particulate accumulation without the clarifier; we'll see.  The top of the media bed is quite a bit higher than the original plan called for - or at least I think it is...I haven't measured yet, but it's at around 40" at present and I don't want it to go much higher.

I'd love to have the space to spread things out, rather than planning to bend and stoop for DWC plant access.  However, this is a trial build after all and hopefully, with sufficient lighting, we'll get a good return.