Good day all, long time creeper but the date draws nearer that I can start my experiments. I guess the most important thing to mention at this stage is that I have no practical experience with AP as of yet although I do consider myself fairly well read on the subject (pause for laughter). With that out of the way let me get right into telling you how I think things should work around here. Not at all of course, but I do have an idea that I would like to hold up to the tempering fires of public scrutiny and ridicule, so please share your vast wisdom with this lowly noob. My idea springs from research into greywater systems and a technique where they make a slow moving, shallow body of water with obstructions (baffles) to allow for the settling of any solid wastes. To these shallow beds are added marsh plants, which are natures uberfilters, and they go to work breaking down the organic waste.
"But wait!" I hear you exclaim, "This idea is nothing new, it is the basis of aquaponics!", but please, bear with me now. It is my thinking that if this marsh set up were placed into the system after the grow beds just before the water is reintroduced to the fish tank. Instead of draining this bed it would run like a slowed down NFT, so even if you are running ebb and flow systems, when you drain your grow periodically this should not affect the outflow rate of your marsh. Ideally I think this could be tuned so that the marsh drains over the "down" cycle of your grow beds, for example, if the grow beds were flooded for 15 minutes per hour, then the marsh would drain over the course of 45 minutes.
To what purpose though? I was thinking that this would allow you the ability to hold more water "in-system" to act as a buffer for your fish. The filtering powers of marsh plants may even allow for a higher concentration of fish to grow beds (if that is what one desired, I like my veggies personally). the last of the potential benefits that I see right now would be the ability to add extra nutrients into the system with a reduced chance of harming your fish. Pathogens from worms or their compost seem to be the main reason why many people are hesitant to introduce them into their aquaponics systems. If there was a "super-biofilter" in place then I do not think that would be as much of an issue and worms could go to work preventing soilless compaction right in the grow beds.
I wonder however how a slow moving body of water would affect the overall O2 levels in the water. This is the only potential drawback I see from my limited perspective, but I would gratly appreciate knowing if anybody has implemented this idea already, pros or cons I have not listed here or even if this idea has simply tickled you. ttfn happy trails.