In a previous decade (ok 4 years ago) I tried to build a pond but life got in the way, there is an old thread but I decided not to necro it since the plans have evolved. Now I am finally back at it construction has started! I collected a few things over the years as deals and money allowed but most of the things I am finally buying now.
So the proposed size and shape are mostly dictated by environmental factors and a very high water table. I have a shallow end which is 2 feet to ground level, it slopes quickly to 3 feed then down to 5.5 feet. I managed to get a nearly flat 8-9 foot bottom on the deep end. The total width is 12 feet moderately consistent. The pond is roughly oval with a max length of just over 21'. I estimate the volume to be close to 6k gal. Based on the fill rate of the hose and confirmed by online calculators. I am above grade by about 6 inches and above the water table by about 2 feet. Really the water table is probably lower but I have springs popping up all over. Including in the pond site. Here is roughly what it looks like.
I tried to get a bottom drain in the low point, but due to the water table I was working in mud. I managed to get a pipe in place but had to abandon it due to muck and mud. I opted to go with a retro drain, reluctantly. On the upside I have a liner in place which has been filled for a week and the bottom firmed up and is pretty flat in the deep end. (people keep asking if it's a pool )
I have some equipment including 2 sequence 750 pumps (lightly used), a 500gal water tank for a settling chamber, a UV sterilizer, two sand gravel filter (and parts for a second), and trickle tower. The SG and TT are already running on a quarantine tank. The quarantine tank is about 1k gal. I will need to expand the mechanical and bio filtering.
My rough plumbing and layout will look something like this
I am concerned about the bottom drain size but I'm not sure I can get a 4 inch in place here, most of the retro ones are 3 in. Based on the size I think it will sweep the bottom ok. Maybe not the sloped part. I hope the TP's and the slop will push stuff down to the BD.
I am also looking for advice on TP placement and general plumbing. I am expecting that the skimmer will feed into one pump, go through SG filters and return via the waterfall. The Bottom Drain would feed the settling chamber then into the second pump, from there into a tt and would also return via the waterfall. I was planning to have the outputs of both pumps split, one side going to filters and one side returning via tpr, with ball valves to adjust flow. I will probably use the UV filter on one of the TP lines, probably the ones coming from the BD. Maybe it makes sense to have one on the skimmer side too.
Filtering in general is area I think I need the most help. I have looked through so many guides and builds my head spins.
I think I will need at least two SG filters and additional TT filters, or some other bio filter.