Hi, you can have an overview of my build here
https://m.youtube.com/watch?v=_XtqNO...ature=youtu.be
I chose to have two wetland areas because I like plants and creating a natural environment but also because it allows to shut one off to work on it or even overhaul it completely if required while the other keeps things going.
Generally if you want to keep fish it is suggested to have wetlands equivalent to 25-30% of the fish pond surface, in my case the pond is 40 square meters (430 square feet) while each wetland is 10 (107 square feet) so 25% each, in your case in proportion you have even more so you are ok there.
The single aerated bottom drain gravity feeds through a 4" PN10 pvc pipe (with a shut off and a drain valve) to a 750 liter or 200 US gal tub while the surface skimmer gravity feeds through a 2" pvc pipe to a 1000 liter tub (housing a few goldfish). These tubs serve as sedimentation tanks, I have put valves on the bottom of both. I would have preferred to use a sieve filter on the bottom drain but I need the pond as emergency water reservoir for my other animals and with a sieve filter dropping the pond level significantly is not an option. I also would rather have had a bigger skimmer and pipe but during the initial months of covid when Italy was hit very hard supplies were hard to come by.
In the tub from the bottom drain I have six Sunsun CTP 3000 l/h pumps, each one by means of a 1" hose is connected to an 8 meter length of 2" pvc pipe in which I have cut slots every two inches or so. In the tub from the surface skimmer I have two of the same pumps each leading to a 37w UV clarifier and then to a similar section of slotted pipe.
I have chosen to use multiple smaller pumps because I have been using them for years and am happy with them (they can be used both in and out of the water), it gives redundancy (if one stops working I only lose 1/8 of the flow), ensures each length of slotted pipe gets the same amount of flow and it allows me to better control how much water goes where, as a bonus they are very energy efficient as long as they don't have to push water much higher - I only have 2-3" to deal with.
The water from the slots in the pipes flows up through the gravel and then spills back in the fish pond