For me, I had a lot of teething problems with my drum filter. It being a single point of failure in my pond, and being somewhat less than bulletproof was a source of stress. Heck. I started dreaming about it, which can't be good
That's behind me now tho. Know the unit inside out, and can pretty much fix most problems. The warranty support, even though it is out of China, is good. As I tell they folk on Koiphen, it is a solid unit for folk willing to DIY. I will be using a somewhat modified version of the drum filter in my new pond. I know where the faults of the unit are. And I know precisely how to get rid of them.
My advise to you would be to plan everything to the finest detail when embarking on your quest. Comb through the details over and over. Once a pond is built, making changes is nearly impossible.
- Size and volume? Affects fish load.
- Placement? Ground beams and buried utilities can be a concern.
- Type? Poured concrete? Prefab Fiberglass? Liner? (not so common in Singapore)
- Technology? Breakback brush and mats filter? ERIC raceway? RDF? Sieve?
Don't worry too much about circulation. Strategically placed drains and returns will sort that out. Airlift pumps can make great circulation devices that move a lot of water for very little energy input.