moldovan said:
Bog option promises less maintenance and cleanup, clearer water. I attached the location where I plan the pond. Starting on top under Japanese maple and going slightly under bridge. Any feedback, ideas are welcome.
This is a tough one. Basically, and I mean basically because there's not enough detail to know much, I would see all 3 choices as basically the same.
I think there is a bottom line in ponds, and pretty much everything else, people who build ponds build a certain kind of pond. Building ponds for profit means building something you can make money on. Customers drive this. Customers like to see tangible "things" on a bid. Like the Aquablox. It's something customers can Google and understand. Contractors make money on things like that. There's nothing bad about it's just the way the world works. Is the cost of the Aquablox needed? Of course not (as far as I can tell).
What you probably can't do is find out the Aquablox isn't needed and going the contractor and expect him to cut the cost by the retail price of the Aquablox. That's part of his profit. In general many pond builders just build ponds and have absolutely no understanding of ponds beyond how to get them to hold water long enough to get paid. Again, not as bad as I'm making it sound, ponds really aren't super complicated. There's not really any reason why a pond builder would ever need to know how a pond works beyond "put this here".
They probably use the Aquablox when building pondless waterfalls and figure why not put it into a pond.
So my advice is to pick the pond you aesthetically like the best.
DIY Pond
This is more of a DIY forum. Many people in your shoes come to forums like this a few years after the pond is in looking for fixes to problems. You're pretty usual for checking into it before hand. But this is why it's going to be confusing. DIY is way different. Different filters, different building methods. And within that space there is a wide range of what people consider "good" or "bad".
It has to be driven by your goals. Otherwise it's a confusing mess. If you say you want 10 goldfish in your pond you have a set of options. And a couple of Koi...entire other set of options. When I built ponds for people I spent 2 or 3 hours talking to try and figure out their desires. These aren't so easy to express I've found.
Filters
Filters are super simple, but people make them super complex. Filters remove stuff. Simple. Do you have a filter in your house for removing feathers? NO! You should get one. Oh, you don't have a feather problem? Well you could in the future so don't you want to protect yourself, family, dog, cat? Don't you love them?
I just happen to sell them. Now, which model do you want. I have Small, Med and Large. How do you pick which size? That's easy. Base it on how much you love your family.
That's silly right? Welcome to pond filters.
Pond filters should be picked for a specific problem...a problem that can be measured. A pond that tests 0 for ammonia on a regular basis isn't going to have lower ammonia if a bio filter is added. But a pond testing ammonia can benefit.
Clear water
It's the number one thing people want. Kind of like loving your family, it's always a good thing. So surprise, surprise, guess what every single filter being sold on the market today do...give you clear water. Do you want Small, Med or Large?
The reality is there isn't a single single in the world that produces "clear water".
Actually controlling a pond to clear water isn't super complex, but there are degrees. More clear = more complex.
For example, is almost guaranteed that your new pond will turn green within a month. It's a good bet. A UV filter is 100% effective in stopping this, giving you "clear". People may not be able to agree on what "clear" means but a green pond sure isn't it. If your builders are specing UV and you're talking about wanting clear water there is a problem...or there is going to be a problem.
#2 speced Ionizer (ion generator) which in theory would do the same job as the UV. There are some issues with ion generators. The main issue is they were never intended to be used in ponds so they don't actually keep a pond clear. They were introduced into swimming pools years ago as a way to reduce chemical use, less chlorine. Ion generators require fairly clear water in order to "work". It can kill a small amount of algae, but needs the chlorine to keep the amount down to a level the ion generator could handle. They've now fallen out of favor in the swimming pool market and in the past year or two they've been looking for suckers in the pond market.
This doesn't mean I think builder #2 is cheating you. He probably is that sucker the ion makers are looking for. Builders don't need to understand ponds, just what customers want to hear. And ion generators have a great pitch...they sound like magic.
UV is proven and inexpensive. All 3 of these pond builders may not even know what a UV filter is even though it's very common. Many pond builder were mowing lawns for a living last week....and will be again next week. Just the way it is.
Bog filter
The term "bog" in the context of ponds is a completely made up term and therefore can mean pretty much anything. The one underwater one to me might be called a gravel bed filter, or a whatever. Specifically it is a "static submerged media bio filter". Break it down. "static" means it doesn't move. That means muck settles on it so not good for the good bacteria. "submerged" means it doesn't get a lot of O2, not good. "media" just means the material, the gravel. "bio filter" means it converts waste from living creatures like fish and other things living in your pond.
The waste bio converts is specifically ammonia and nitrite. That's it. People will say it "keeps pond clean", "keeps water clear", etc. Whatever they want to believe. But ammonia and nitrite are clear.
People will say "oh your pond is green, you need a bio filter". Well algae consume ammonia directly. They prefer ammonia over nitrate because it's easier for them to use. Algae is a bio filter. They remove ammonia. A green pond will have 0 ammonia. Adding a bio filter will do nothing.
Bio filtering is normally done by a few species of bacteria that are everywhere. Inside pipes, your pump, on the liner. The question of whether you need to build more homes for the bacteria is purely a function of how much ammonia there is. That's found with a simple test kit. There are some general guidelines. Like if you said you wanted to add 10 full grown Koi on day one we know you'd need serious bio filters. If you're adding 10 tiny goldfish you don't need any bio filter beyond what the pond will already provide.
A bog filter outside of the pond is the same deal with the added feature of being a "settling tank". Over time, like 2,3,4,10 years after the pond is built decomposing stuff will start to appear suspended in the water. This can make water less clear. A settling tank's job is to allow that suspended matter to fall out of the water column. Doesn't trap it, just makes the water so calm the matter falls and stays.
Bog vs whatever
Which is a better car, a Toyota Prius or a Telsa Roadster? Silly question, they have different purposes.
Bogs are not good bio filters. Meaning that pond for pound they don't convert as much ammonia as other filters. But the question should be will it work well enough for your pond. Probably. No way to really tell without testing the water for ammonia. The "may be few Koi" leaves that question up in the air. How much food you plan to feed is the actual way to predict.
Settling tanks are not the best filters for removing suspended waste. Mainly because the waste isn't removed. It continues to decompose into such small bits that it once again becomes part of the water column. In that form we call it DOCs (dissolved organic compounds or carbon). It acts like soap and you come out to the pond one morning and see soap foam floating on the surface. I don't like the look of it myself.
It is what it is
I wanted to explain one thing...this can be very complex or very simple. The middle ground is where it gets weird. If you try and figure out a little bit you're likely to get fed a bunch of myths and all will be very confusing and make little logical sense. Unfortunately there's not a single book to explain it in 10 words or less.
So imo I suggest one of two paths.
1. Hire which ever builder you like and enjoy whatever comes your way.
2. If you're interested in the hobby dive in. Build the pond yourself even if you hire out the labor.
Splitting the difference just seems to drive people crazy and unhappy. Been in pond forums for 10-15 years, see it like once a day.
