Thanks "/>to the help of many KP ponders I finished my koi pond 2 years ago. (I haven't posted pics of the finished project yet as I am still working on the landscaping around it .... and I wanted a good photographer with a good camera to take them so it'll look even awesomer than it really is ).
It is 10 x 15 x 4' 1/2 and the kids have been known for falling into it (with goggles and snorkel ) and struggle to come out for hours !! They are a great help with picking up rocks and sticks from the bottom and sweeping it.
My wife and I are now considering building a huge swimming pond the size of our entire backyard "/> (we live in a small city lot), we (I) have read lots of books and internet info on the subject, and have followed lots of KP threads, learning a lot . But we have lots of questions as to which way to proceed: filtration, wall construction, plumbing , grading, etc. . .
Right now we are thinking of an oval (ellipse) shape, 50x25' !! , 8'on the deep end and 4' the shallow end (that should be approx 44,000 gal if I calculated it right). We would also have a separate bog pond, adjacent, with separate pump & plumbing (ie. just for looks), that may or may not be connected with the main pond.
There will be no fish in the new pond, with the exception of a few mosquito fish.
Of the 4 main ways to build a natural swimming pool I am thinking of building what this book calls type 4, which is the one that has a high flow rate (into a large quantity of bio media) and needs no plants , bacteria in the bio-film apparently will do the job.
Of course having almost no fish waste, the chemistry of the filtration is very different from the one that occurs in koi ponds, however I think that it must be very similar as debris that falls into the pond need to be collected and discarded before they decompose in the same way it's done in a fish pond. And water quality for humans must be the same, or similar, to the one in koi ponds. So here are a preliminary list of issues I am confronted with:
1) FILTER: At first I was thinking about building a huge manhole to host a huge SC and a huge bio-filter
(either cement built chambers or 275 gallon tanks) but now I'm thinking of buying a sieve and / or a Nexus. Can these two replace SC & BF ? It should have a water turn over of 1, 2 times a day ...
2) PLUMBING: I was thinking of two 4" bottom drains (both in the deep end), both plumbed on the same 4" line (to avoid risk of suction). Does the line from the BDs have to be sloped down a bit (or be horizontal) all the way to the SC? In which case, I'd have to build the manhole 8' deep. . . if I bend / elbow the pipe upwards, wouldn't that cause clogs?
I've written too much already. I have more questions but I'll stop here for now.
Any guidance / advice you have to offer would be greatly appreciated. TOM