A koi pond can be either high maintenance or easy care depending on variables. I strongly recommend you do some research on various forums (like this one! But there are others). You very much want to get references from the company who installs your pond (or upgrades/renews it). I’ve kept koi in the past, and frankly my first pond was not set up correctly – it was a weekly hassle and the pond never really looked great except the first year. I dreaded cleaning it.

As an older couple now, DH and I have almost finished our latest pond. We’re far better informed. The following was on my wish list:

• Heavy Duty Liner – a given. EPDM, 45 mil. You want to make sure the company also uses padding under the liner. We used geo cloth, some use carpet, some use carpet padding. Prevents rocks and roots from poking holes in the liner.
• Bottom drain – this makes draining your pond so much easier. Of course, you can always just buy a cheap pump.
• Bio Filter with backflush – these are not inside the pond, but rather in a small pond/pump house or buried up to a certain point. To clean the pond, you simply turn it to backflush, run it, then turn it to drain, and allow the sediment cleaned in the backflush to run out. This will need to be done every week to every month, depending on your pond (and at first, every other day as new ponds have a lot of dirt in them). Many bio filters also have settings that recirculate rather than clean (handy when adding fish medication to pond). In the winter the bio filters are cleaned, lids removed, water sucked out. I wouldn’t have a pond without a bio filter. It’s just much easier to clean.
• Skimmer – well placed, with water circulating around your pond, the skimmer will pick up sediment/leaves/etc. floating on top of your water. These can be cleaned weekly to monthly, depending on your pond. Easy to clean. You will need to remove the net and empty it more often if you’ve got trees/leaves in the fall.
• UV light – some like them, others don’t. I do. Ours is a smaller one, and takes a full day to filter the entire pond (1/4 of the water goes though it each pass). These help keep your pond clearer.
• Falls/aeration – this is a given. You need oxygen in your pond, either via falls or fountain or aeration stones.
• Pump – another given. This pulls the water out of the pond, into the bio filter, then into the uv light filter, then back into the pond. We have a large pump, installed next to the bio filter and uv light (not in the pond or skimmer).

All this means you need electricity and a place for all this stuff (the skimmer goes at the pond). Now, others use a far more natural method, and they can explain that to you : )

• Plants – always beneficial. They’ll feed your fish, provide a healthy balance to your pond. Water Lily’s and submerged plants are good to have. If your plants will survive with bare root planting, this is a good way to go (plant the roots in pea gravel filled pots, no clay or dirt. If you need clay, get the right kind, and top with pea gravel. Then don’t mess with them until you must! Make sure if you use pond clay your pots can be overturned by rambunctious koi – they can make a huge mess and dirty up your pond in no time.
• Fish – ha! I said I had koi… they poo a lot. I mean, a lot. So we are going with shubunkin this time around. Heartier, less expensive. Goldfish with long flowing fins/tails. And you can have more. Buy from a pond dealer in your area and look for healthy fish. Another reason to go with goldfish – comets, shubunkins are not only heartier, but cheaper, and if you’ve got cats or wildlife, expect to lose a few or all beloved fish. Happens.
• Feeding – don’t over feed. Nothing will make your pond dirtier than overfeeding. Dirty pond = high maintenance = dead or sick fish. Some never feed their fish. I wouldn’t feed more than 3 times a week if you’ve got plants and algae, and you will have algae – it’s part of the healthy balance.
• Don’t sweat the small stuff – every spring most ponds have algae blooms and we ponders often call it pea soup. Looks nasty but with a well balanced pond it will clear up in time. If you see too much algae, stop feeding your fish and let them eat it.
• You’ll want a water testing kit. I recommend establishing plants this next spring well before you introduce fish. Slow is good : ) And do not overload your pond with koi or goldfish – best way to have an unhealthy pond.

So, how hard is it to maintain a well-balance, properly built, well planted pond? Not hard at all. You might never have to empty your pond or you might have to each summer. Depends on weather, surrounding trees, shade/sun, feeding habits. A bio filter with backflush makes cleaning the pond so much easier – I don’t even get my hands wet! I never put any additives in the pond… except if I have to drain and replace quite a lot of water and dechlorinate. Good Luck!

I'm going to add this: We wanted someone else to install our latest pond. It was a disaster. He did everything wrong, concentrating on looks rather then getting it technically right. Then he walked off the job as it was beyond his company's abilities (just a 750 gallon pond!). DH and I have worked tirelessly on it every weekend to get it up and operating correctly - not to mention all the leaks. Get references, then get some more, and go look at the ponds!