Having trouble figuring out a filter solution

[BennyLava]

As I said in another thread, I am in the process of upgrading my pond from roughly 350 gallons, to 2500 gallons. Still not a large pond by most of you guy's standards. I have decided that I am indeed going to attempt a waterfall, so I am wondering if I should have one of those filters that is sort of installed inside the waterfall. All I have right now is a lowboy in-pond biological and mechanical filter all in one. And it's only rated for 1000 gallons.

I have to admit that I am kind of at a loss as to what to do here. I am not opposed to building my own, but those 55 gallon drum monsters that you guys build seem to be pretty serious overkill for a 2500 gallon pond. Or am I wrong about that?

I am going to have a bunch of plants, so that will help with the nitrates part. But I could use a little help on finding an easy to clean, biological and mechanical filter. I guess those can be separate if need be. I don't need an all in one type of deal. Any help would be greatly appreciated.

 

[koiguy1969]

overkill..not at all..no such thing as too much filter. i use a 55 gallon filter on my 800 gal basement pond and a 70 gallon skippy style on my 1200 gal outdoor pond... both DIYers. you can find both here in the DIY section
https://www.gardenpondforum.com/koiguys-70-gal-skippy-style-filter-t5089.html, i even sell the weirs for the falls.

 

[koikeepr]

koiguy is right, benny. If you are building a 2500 gal pond, you will need at least two of those 55 gallon filters (or at least a 100 gallon stock tank). The rule of thumb is one 55g drum per 1500 gals. And since most of us overpopulate our ponds, it's always best to go a little higher in filtration.

If you have an in-pond filter, you need to get that thing outta there as those are largely junk.

Here's a photo of someone who turned a 100g stock tank into a waterfall filter, with instructions. They are using it in a commercial setting, so the final pic isn't very attractive, but this can be hidden behind a berm, wall, shrubs, etc. You could buy the weir from Koiguy, too, to fit it.

I am making a similar filter, tho it will not have a waterfal weir. It will just be my bio filter. I will fit it with strapping.

 

[BennyLava]

Ok I have no problem with using those massive 55 gallon drum DIY filters. However, I do have to ask:

How hard is it to clean them out? Seems like that would be quite a task, indeed.

 

[koikeepr]

Oh, not at all. They have a waste dump pipe that you open up and the cruddy water just whoooshes out! Couldn't be easier!

 

[BennyLava]

Nice. Do yall bury yours somehow? How do you obscure those big giant 55 gallon drums?

 

[koiguy1969]

https://www.gardenpondforum.com/koiguys-70-gal-skippy-style-filter-t5089.html
check it out, a great filter, easy to build; this will show you ...i sell the waterfall weirs for this filter too.

 

[koikeepr]

My current barrel is buried under ground in a filter pit. If you do this, then you have to have a sump pit below so that you can dump into a lower bucket. I can tell you that though it works perfectly, it's a PITA with the constant bending down.

In my new pond, I will have a massive 150g stock tank on the side of my house and then I will just screen it with some lattice or something like that.

 

[BennyLava]

I think that maybe I have a lot to learn about filtration systems. For example, I had no idea how my septic system worked until my grandad showed me. Basically, raw sewage gets turned in to clean, (well, relatively clean anyway) clear water. I found that to be absolutely amazing. Literally on one side is sludgy brown sewage, and on the other side, after the bacteria have had their way, is clear water. The raw sewage just ceases to exist like magic.

So is that how these 55 gallon drum filters are designed to work? Make bacteria break everything down so much that you are just left with clear water? And because of that, little mechanical filtration is needed??

 

[koikeepr]

well, not quite as dramatic as in a septic.

In a septic, which I have as well, there's lots of dwell time because water in flowing in when toilets are flushed, etc. So, there's lots of down time with no activity and plenty of time for the bacteria to do their thing. In a septic, when everything is working properly a tough crust actually forms over top (strong enough that I've seen septic guys walk on it), while the bacteria is converting sludge below.

In a pond filter, water is moving through the filter 24/7/365. The water isn't technically being "cleaned" because the detrius is still in the water. Your mechanical filtration is hopefull trapping crud and keeping it one place so it doesn't continue to pass through the rest of the filtration system. You're cleaning it as you flush out your barrel and rid the crud out. You are diluting it when you do partial water changes (that's why they are so important), and the bacteria is trying to do it's part in converting some of the bad stuff into good stuff.

Mechanical filtration is very much needed. There are three types of filters: Mechanical, Bio and Bio/Mechanical. Let's look at each:

Mechanical will simply remove crud as it passes through a filter sponge to trap debris. This can be a skimmer, a pressure filter, or something with sponges for example. It can be a settlement tank or in my case it's going to be a sieve that will catch crud so that it is out of the water column. Inevitably, some of these can also provide an itty bit of bio (not the sieve), but it's never enough.

Straight Bio Filter: Does not clean water as there is no media to trap it. The media in this filter just gives bacteria a happy place to live and do it's thing. In my case (and in the case of that waterfall filter) the medis strapping. There are no sponges. I have this because the sieve is already acting as mechanical fitration before it, so since there is no poop in the water after that, I just have strapping in there to be home to bacteria. These type of filters work in tandem with a Mechanical filter as mentioned above. You can't have one without the other.

Bio/Mechanical (most common): Does the task of both in one unit. Such as in a 55 g drum. You can see this in my DIY barrel pics thread. I have water entering on the bottom where it swirls around to sink the crud. My next layer are two matala mats to act as mechanical filtration, so the crud doesn't keep climing up the barrel so that it can be easily flushed out when I open my waste pipe. Above that I've got bio media (bacti-twist) that acts as the home for the bacteria; and finally the "cleaner" water exits to my pump.

Hope that helps a tad.

 

[BennyLava]

Ok two questions.

1. If you have a straight bio filter, then why do you need to pass any water through it? If it can't actually catch any fish crap or other debris, then why do you run the water past it? Couldn't you just have a whole bunch of those bacterial balls in some kind of container at the bottom of the pond?


2. How does the flush actually work on the 55 gallon drum filter? In my mind, you would need to somehow reverse the flow of the water in order to get all of the crud flushed out. Otherwise, how do you get all the stuff that would be sticking to the bottom of the mechanical filter element? Or are you only going for some of the crud? And how much of the crud that is trapped in the filter gets removed with each cleaning? 50%? 75%?

 

[koikeepr]

you don't want bio balls at the bottom of the pond as not only are they unsightly there, but they are not gathered up together. They will make your pond floor hard to cleab.

You get the stuff out by flushing the waste pipe. You can see this clearly in all the examples of 55g drums posted on our DIY and construction sections. Please give a read and you'll see it.

 

[DrCase]

You would not believe how much crud you catch in the bottom of the 55 gal drum
gravity keeps it down there...i dont worry about what is still left in the media
Once you open the dump valve on the bottom you have 55 gal of water in reverse to clean the system

 

[BennyLava]

Once you open the dump valve on the bottom you have 55 gal of water in reverse to clean the system

Ahh there we go. I knew I was failing to consider something.

 

[BennyLava]

I searched and I saw that there are actually a few DIY 55 gallon threads over there. Which one is the most recommended to follow?

Also, is that the only filter that you guys run? Or do you also run the little waterfall skimmers?