Wow, that's a lot of gallons. In an aquaponic system, you want to cycle through your systems water at least once an hour. Are you planning on replacing your filters completely with growbeds? Or just supplementing filtration?
Flood and drain rates are all over the map and yours seems OK to me. Mine are about 10 mins flood and 20 drain. That's a huge pond you have but a very light stocking. All of the surfaces in your pond are also part of the biological filter so all total that's a lot of filtering. It will interesting to see what happens as the fish population increases. It all looks great.
Like George I think your flood and drains rates are great. However I don't think you need to cycle through your water once an hour. I think that is a good idea if you have a high density of fish, but in your case I would recommend moving 10 to 20 gals of water per lb. of fish.
Hope that helps, Josiah
Hello Josiah - please post some recent photos. You have the most unusual tank ever.
Yeah, Wendell your fill/drain times should be just fine...and I totally agree with Josiah in that there's really no point in you cycling through all that water once an hour with that fish stocking density.
The plants and bacteria are fine as long as the media is not completely drying out between 'floodings'.
Now, flow rates can affect other things like solids and fines settling, O2 replenishing, stratification of the water column...blablabla and all those things certainly have their place (even if sometime that 'place' is just academic contention)...but really, with what you described, it doesn't seem like you'd need to worry about any of that. Just keep the media from drying out and you should be fine IMO.
I'm uploading some more pics now :-) If you would like to see a lot more, I have pictures and videos here: