Reddit mentions: The best pond filtration equipment

The pond looks to be a great one for longterm viability. It's deep, which is good to keep the fish alive during the winter, and it's long and narrow. These are a tad easier to maintain because the water can follow one path. From Plant Filter / Waterfall to pump. This keeps the water moving which thus thwarts as many anerobic zones from building up. (Anerobic means no oxygen. It's a bacterial zone where Nitrates are converted to Ammonia - fish don't like ammonia. This is the exact opposite of what you want to happen.)

To start with, plants are your friend. They are more vital to the wellbeing of a pond than fish. You can have a pond w/ no fish and just plants and it's great, but if you have a pond with no plants and just fish, it's a horrible situation. One that is full of chemicals and stress over diseased fish.

Regarding the plants, when they multiply that means they're healthy. It's the same thing that all plants do, but pond plants -since they have ample and abundant water and food - grow quickly. This is good, but better to keep it in check. There are three basic types of plants you need for proper pond balance and filtration.

• First is an underwater grass. The ones I use the most are Anacharis and Hornwort. YMMV as I'm just seeing that Anacharis is prohibited in Chicago. These plants do some decent filtering, but work mainly with the oxygenating of the water. Photosynthesis + daytime = Dissolved Oxygen for the fishes to breath. (Note: I hear Hornwort, under certain conditions, can produce more CO2 during the nighttime hours than it produces O2 during the daytime hours. Apparently fish have died as a result.)
  
  
• Second is a plant to shade the pond. This can certainly be a tree above the pond, but otherwise plants like Hyacinth and Water Lilies will do a good job blocking the sun from getting into the water. The reason for this is really just to thwart algae. When algae has light and food it will grow. So the whole point here is to thwart algae on all fronts while trying to maintain a good looking pond.
  
  
• Third is the most important. They are labeled collectively as 'Marginals', but really these are any plant that grows up outside the pond. 'Marginal' as in they grow on the 'margin' of the pond. They vary from bushy - Mint, Lizard Tail, and Celery, to tall and thin - Horsetail, Rush, and Iris.
  
  My baseline for an ideal plant filter, which in your case would be a smallish stock tank / waterfall weir on one side of your pond full of Mint, Corkscrew Rush, Horsetail, and some tall plants like Umbrella Palm, Giant Reed, Cattail. All while making sure you have room for a Canna. These are some of my favorite plants. But you can pick and choose as you like. The essential point is to have a variation of small / bushy and tall / thin plants as they have different filtering qualities. I am told the tall and thin ones are great for good, heavy duty, filtering, whereas the bushy ones are great for quick filtering. Either way, they're pretty. This stock tank gets water flowing into it, pushed through the plants, and then lets it go through a waterfall.
  
  Now all this is just to process the Ammonia waste from fish. Ammonia kills fish, and you really can't see it. Apparently a reddish tinge develops in the water, but I've never seen it. But, fish produce Ammonia, so if you don't have your three types of filters you will have issues utilizing all these awesome plants to keep your pond clean.
  
  
• First is a Mechanical filter. This is just something to get the floaties out of the water. Something that will coat the roots / block the water flow / gunk up the pump. Just get it out.
  
  
• Second is a Biofilter. This is a colony of Nitrobacters whose sole purpose in life is to convert Ammonia into Nitrates and Nitrites. You can read more about this cycle here. It's pretty important. Now, MY favorite biofilter is a 5g bucket of lava rocks surrounding the pump. I know it's not the prettiest nor easiest way to do things, but it gets the job done and it's cheap. If you'd like you can use items like Springflo and whatnot. But essentially this is just a home for your bacteria colony, which are living everywhere in your pond if the water is slow enough, but having a proper filter is important.
  
  
• Third is the plant filter. Using Marginals and other such plants you position them in such a fashion where the water is forced to go through them. This allows the water to move through the root systems and get stripped of its Nitrates. By doing this in an overkill fashion you won't have any algae problems because the algae won't have anything to eat.
  
  Doing something like this, or an approximation of this, will keep the pond clear and the fish happy. You can get Nitrate and Ammonia testers to see what your levels are in case that might be the issue. I must say that multiple fish without any plant filtration and no algae makes me suspicious.
  
  EDIT: Things

For clear water you don't need great filters. What is more important is building a system that is easy to clean because dirty filters don't do shit. To find the best filters you should look at what aquariums use, specifically reef aquariums. Clear water is far more important in an aquarium than in a pond. And Reef aquariums need to filter out a lot of things that you can't see to keep the coral healthy.

These sock filters are great, and protein skimmers will pull out all the organic waste your fish produce.

You can also use a "reactor"to extract any and all other chemicals by filling the reactor with different kinds of medium. These are very simple and can even be built with pvc pipes. By removing all of the phosphorous for example you can prevent algae from growing because it requires that ingredient.

No the pump pictured is not a a 2 in 1, I'm surprised the pond has living fish in it without a filter though! And I'm wondering where the bio-balls came from! The filter has to be outside the pond otherwise you'd just have all the fish waste at the bottom instead of floating around which is pretty much just as bad.
Look up oase or green genie or nexus or rdf filters, the last two being quite a big step up in price. Basically filters are giant buckets with sponges and media and mesh in them to stop fish waste and dirt circulating and reduce ammonia and harmful toxins in the water.
Here is a filter that's quite overkill but it will keep your water perfect, is easy to set up with your current piping and has everything in on small unit, not to mention is amazing value.
https://www.amazon.com/gp/aw/d/B016M6DODK/ref=mp_s_a_1_6?ie=UTF8&qid=1503702744&sr=8-6&pi=AC_SX236_SY340_QL65&keywords=Filter+pond&dpPl=1&dpID=419sZFALDtL&ref=plSrch

I wouldn't be as concerned with the mineral content as I would with water treatment chemicals. Chlorine or chloramine would be the two biggest things I wouldn't want in my bubble.

RO is best but if you're on a budget, I use one of these..

Hydro Life 52700 Inline Water Filter (with Flexible Hose Protector, Hydroponics C-85) https://www.amazon.ca/dp/B01N8TYQ9W/ref=cm_sw_r_cp_api_i_Z74hDbFT8WC9Z

Great for living/no till soil as well.

https://www.amazon.com/Aqua-Flo-Coarse-Black-Universal-Filter/dp/B071YNPN9J

I used these in the past. Just cut them into pod sized pieces and then split it halfway down the middle. Put your seed or sprout in there, close it and you're good to go. Definitely safe for your water and flows very well.

Get a filter with a UV light on amazon, it'll clear the water right up and requires probably the least amount of work. the bulb will need to be changed every year, but they only cost about $20 for 2... you'll also need a pump.

I struggled doing it without a UV light for years... then finally got the aforementioned filter with UV light and it fixed in 2 or 3 days. But as I said, stay on top of the light.

I have this one, it's pretty big...

https://www.amazon.com/Goplus-Pressure-Filter-4000GAL-Light/dp/B016M6DODK/ref=sr_1_2?crid=AX1B1LXYPVUY&keywords=goplus+pressure+bio+filter+4000gal+with+13w+uv+light&qid=1565725957&s=gateway&sprefix=bio+filter+UV+light%2Caps%2C252&sr=8-2

I installed this yesterday. Seems to be working ok.
Jebao SK-30 Floating Pond Skimmer 660 GPH https://www.amazon.com/dp/B00BKP8J1G/ref=cm_sw_r_cp_api_cFUhzbMXPJMP8

I think they might be these-

https://www.amazon.com/Atlantic-Water-Gardens-EcoBlox-Matrix/dp/B003LM7CMS

I don’t have the prettiest set up, but my indoor stock tank pond is functional and affordable. I run a Beckett Pond Filter in this 110 gallon tank. The basking dock is just a Penn Plax dock that I suspended with bungee cords. My turtle just knocks the suction cup pillars that came with it over.

I do have plans to add live plants, including planters around the sides eventually.