Backyard Aquaponics
A place to discuss aquaponics

I have a Jebao 1200GPH pump, this model: http://www.amazon.com/gp/product/B00SW32BUE?psc=1&redirect=true&ref_=oh_aui_detailpage_o05_s00

The packaging on the pump says it's suitable for handling solids up to 6mm which makes me think it should have no issues pumping fish waste and uneaten food matter.

The pump has male threaded 1-1/2" ports for both the intake and output. Would it be a good idea to plumb a SLO pipe array at the bottom of the tank directly into the intake on the pump?

I'm noticing a significant amount of solids at the bottom of my FT already, and the system is relatively new. I think it might be contaminates that have fallen in from the environment, for example fallen leaf/tree seed matter from nearby trees that gets blown in. The water is very cloudy right now, with lots of visible particulate matter. I do have 24 channel catfish in the tank currently.

In your fish tank you have , ‘Big bits’ and ‘little bits’ Swirl and RFF filters are good at removing big bits. Little bits, Suspended solids are harder to remove. You need finer filters to remove them. Your pump may accept 6mm solids but I bet it macerates them.
The smaller it makes them the finer the filter required to remove them.
So the question really is. How do you then handle them?

My gut instinct is "keep adding more grow beds with lava rock until there's enough surface area". I suppose the alternative is a separate mineralization tank. Everyone has different opinions how how to deal with (or not deal with) solids in an AP system.