ginger_biscuit69 said:
was there a need for the increased flow?
stalked your profile, see it's about 50,000l concrete in a bowl type of formation. Assume the bigger pump is in that central recess and the rest of the pond is leaning down towards this point.
All correct. Do I need more filtration? Biologically/chemically, no. My fish load is extremely light for such a large pond, I have absolutely no ammonia or nitrites problem. I probably wouldnt have one without the 15K pump and DIY filter, as there is also a fairly large iris bed (although its in clay and water is merely running over it, not through it. Very poor design, but it is what it is. Its fed by a third pump btw, not sure about the capacity, but I estimate around 5-6000L/hour).
Some Koi have grown huge and survived for decades in this pond with just those irises and that pump. I added all the rest recently, as, well, those koi didnt survive in the end (mass die off from parasites a few years ago) and the entire pond had become a giant mud pool.
Mechanically, I need everything I can get to have any hopes of keeping the water somewhat clear. The pond is surrounded by overhanging trees and bushes, and there is a slope. The amount of stuff falling in is absurd and not all of it floats. But much does, so I really need a skimmer. Ideally Id need many skimmers in fact, but if youve seen pics of the pond, you may understand its not easy to install.
As to this:
Assuming the filtration is coping physically with the 15000l/hr pump, id use the 8000L placed with the output firing straight out the unit, to make a pond current spinning around, turning the entire pond into a vortex with the large central pump taking out this waste to the vortex then filtration?
Thats pretty much what I was thinking, and why I said Id add a T and use part of one pumps capacity for just that purpose (perhaps with an added venturi, although I already have a large airpump with a disc in the pond and several stones in the filter).
A few problems with that though:
1) my waterlilies dont like this idea
2) I already tried it for a while, and the pond is not uniform enough to create a real vortex. The pond is formed like a croissant and the resulting flow is complex. Pumping water around does help, but not like it would in a round pond.
3) im gonna need some pumping capacity for a makeshift "skimming lava filter" that I intend to make in one of the "croissant tips". See here:
https://www.gardenpondforum.com/lava-filter-t7926.html
Now believe it or not, I still have a 4th pump laying around, its a "basement pump". Its extremely powerful, 25K liter per hour or so, but its also a power hog (1000W). So I think Ill use that pump for the vortex, but put it on only a few quarters of an hour per day on a time clock. Then use the 8000L pump for the lava bed/skimmer I have yet to make, and I might as well feed that back to my biofilter. Not sure about that yet.
Anyway, I appreciate your thoughts.