New DIY filter design help

[Ijy14]

Hello,

I’m new to ponds, we currently bought my fiancée’s grandparents house when theypassed in which they had a pond in their garden. I apologise in advance for the long post.

Pond Overview:

The pond is kidney shaped and holds approx. 3500 litres which has been dug in (so the top of the pond is at ground level). It is currently supplied by a submerged 5500lph pump (this has just been replaced), going into a UV and finally into a very old Biotec filter (which doesn’t really work) and back out the the pond. The UV and filter are just above the top of the pond (ground level). It currently has 10 fish. 6 small goldfish (4-6inches) and 4 larger fish approx 10-12inches ( I want to say these are koi but looking at how bad shape the pond quality is in I doubt they are as they are still alive and seem quite happy). I think this is a too high volume of fish for the size of the pond.

Unfortunately, the pond hasn’t been looked after, I don’t think there has been any proper water changes and a full clean (no bottom drain installed) for at least 3 years.

Plan:

I’m looking to get the pond fully cleaned, drained and refilled etc. At this time I’ve been looking at DIY filters due to having the majority of the stuff around and no money for a proper one. I’m not looking for this to be amazing but hopefully a definite improvement on the fishes current situation (and hopefully build on this once i get more knowledge).

I have done a basic filter layout but please let me know if this could be better optimised and anything I’ve missed or could help. I do have some questions and know some (if not all) of the design will need changing.

Design:

Sorry if the terminology isn’t correct, I will add question marks on anything I’m unsure on. Here are the design pics:

ED43-CAB7-BD48-4516-9-AF3-8310-D2-B3-B270 hosted at ImgBB

Image ED43-CAB7-BD48-4516-9-AF3-8310-D2-B3-B270 hosted in ImgBB

ibb.co

16459-AFB-C26-D-44-F5-A25-C-6247924-A853-F hosted at ImgBB

Image 16459-AFB-C26-D-44-F5-A25-C-6247924-A853-F hosted in ImgBB

ibb.co

The submerged pump has a 32mm flexipipe connected to it. This will go out of the pond and up approximately 2ft into the UV via a hosetail. Another flexipipe will go into a hosetail, then a 3-way ball valve (supply filter, drain & potential backflush?) and eventually into a bulkhead on a 55 gallon plastic drum (approx 2ft from bottom).

(All internal piping will be push fit where possible) The inlet will supply a shower (inlet pipe into a Tee then create a square with drilled holes). This will filter through some foams (varying grades) the through some bio balls to the bottom on the filter tank.

On the filter bottom in the middle is a drain with a elbow directed to the bottom(approx 3 inches above bottom of filter). This fed to a outlet bulkhead then 3-way ball valve (connected to the inlet in the same way via hosetail and flexipipe for backflushing) then hosetail to a flexipipe which is situated in the garden to drain (approx 10ft away).

Approx 6 inches from the bottom just below the bio balls in the outlet to the waterfall. This goes up to via an elbow to a outlet bulkhead (approx 1.5ft - in between foams and bio balls). I was going to add a valve for piece of mind. Which again is attached to a hosetail and flexipipe to the waterfall (approx 1 ft from ground level).

The water fall has 2x25mm threaded inlets so I will have to use a reducer. I plan from the outlet (32mm flexipipe) to go into a Y splitter and 2 separate flexipipe into a reducer then more flexipipe (25mm) to connect to the 2 inlets via hosetail at the bottom and back of the waterfall.

I will also have an overflow. There is a pipe (approx 2.5ft from the filter bottom / 6 inches above the inlet) which will feed into a elbow then the bulkhead outlet. It will be connected in the same way as the waterfall outlet (*this shows that is higher on the diagrams but it will be adjacent*). This will feed a flexipipe (32mm) to a bulkhead outlet just below the waterfall.

I’m still undecided if a Backflush is essential but I think I will install it for ease of cleaning if it will work. This will be connected to the inlets 3-way ball valve to the drains 3-way ball valve via hosetails and flexipipe.

I will also put in an aerated pipe for cleaning. This will come from the top of the drum down to next to the start of the waterfall outlet pipe (approx 6 inches from bottom) and will consist of a shower as before.

When cleaning I can drain, clean the foams, fill and drain again. Fill and connect the aerator and drain again.

All piping will be 32mm, the internal piping will be pushfit for ease. All elbows will be sweeping bends rather than knuckles.

Questions:

I’ve read the the outlet should be approx twice the size of the inlet. Would a 38mm outlet be better (and work)?

Would the splitter work or can I just supply one of the waterfall inlets from a single pipe into a single reducer.

I’m also worried that the filter drum will overflow, do you think this will be the case? I can I install a valve to control the water flow from pump but reluctant to do it as I don’t want to strain the pump.

Any advice or help would be greatly appreciated, I understand the design will not be perfect but as long as it works until I can do better I will be happy.

 

[Nevermore44]

So your pond is 925g for us US folk and does sound heavily stocked, though it also depends on your feeding routine as to you filter setup functioning well enough to keep up. If you are going to keep the heavy load with a DIY barrel filter, I would look into a “sand and gravel filter”(S&G filter). There is a lot of info and videos on Youtube about them. Do note that in reality they use a size gradiation of stones down to a grit size… no sand is involved.

I currently run one for my 1000g/3800L pond that is heavily stocked with koi that I feed daily… and can’t be happier. For your filter… I hear a lot of people not liking the cleaning routine of mats and that they clog up fairly quickly. For a S&G filter you can clean the whole thing without getting your hands wet. The finer gravel and grit acts as the filtering mat. So during the cleaning phase, air that is pumped down to the bottom then rises up through the media and essentially breaks the “mat” into pieces as the air bubbles through it. The grit is “boiled” with the air essentially… releasing all the filtered muck which is drained away. Then when you are done, the grit settles back down and forms the “mat” again to filter. it’s a great set up. The air is pumped down to the bottom with a 1hp spa blower or I just use a small shop vac to do the same thing.

They also act as a bio filter since the media is also a great surface for aerobic bacteria to grow and do their thing. I ended up added a second smaller barrel to my set up full of feather rock to add more bio filtering. The S&G filter outputs to the top of this barrel and the water showers down through the porous rock before returning to the pond.

If you have the room, others can chime in on a bog filter route as well.


For you specific questions…
-Outlet sizes. Yes the outlet should be larger then the inlet since it’s not under pressure on the return. (mine is 2” inlet and 3” outlet)
-Splitter on the return… yes but you might need to add valves to control each branch to some extent
-Overflow concern…. You are going to want to put a valve and a check valve on the inlet side to control the flow in general. This will not burn out a filter, it just effects the head pressure. And as long as your outlet and overflows pipes are of a decent size, you should be fine. You also need to make sure you keep a lid on the filter. I’ve heard some people get an errant brand/leaves fall into a open topped barrel… block the outlet and then water starts overflowing.

 

[j.w]

@Ijy14

 

[Ijy14]

So your pond is 925g for us US folk and does sound heavily stocked, though it also depends on your feeding routine as to you filter setup functioning well enough to keep up. If you are going to keep the heavy load with a DIY barrel filter, I would look into a “sand and gravel filter”(S&G filter). There is a lot of info and videos on Youtube about them. Do note that in reality they use a size gradiation of stones down to a grit size… no sand is involved.

I currently run one for my 1000g/3800L pond that is heavily stocked with koi that I feed daily… and can’t be happier. For your filter… I hear a lot of people not liking the cleaning routine of mats and that they clog up fairly quickly. For a S&G filter you can clean the whole thing without getting your hands wet. The finer gravel and grit acts as the filtering mat. So during the cleaning phase, air that is pumped down to the bottom then rises up through the media and essentially breaks the “mat” into pieces as the air bubbles through it. The grit is “boiled” with the air essentially… releasing all the filtered muck which is drained away. Then when you are done, the grit settles back down and forms the “mat” again to filter. it’s a great set up. The air is pumped down to the bottom with a 1hp spa blower or I just use a small shop vac to do the same thing.

They also act as a bio filter since the media is also a great surface for aerobic bacteria to grow and do their thing. I ended up added a second smaller barrel to my set up full of feather rock to add more bio filtering. The S&G filter outputs to the top of this barrel and the water showers down through the porous rock before returning to the pond.

If you have the room, others can chime in on a bog filter route as well.


For you specific questions…
-Outlet sizes. Yes the outlet should be larger then the inlet since it’s not under pressure on the return. (mine is 2” inlet and 3” outlet)
-Splitter on the return… yes but you might need to add valves to control each branch to some extent
-Overflow concern…. You are going to want to put a valve and a check valve on the inlet side to control the flow in general. This will not burn out a filter, it just effects the head pressure. And as long as your outlet and overflows pipes are of a decent size, you should be fine. You also need to make sure you keep a lid on the filter. I’ve heard some people get an errant brand/leaves fall into a open topped barrel… block the outlet and then water starts overflowing.

thanks Nevermore for the reply, I think I do want to stick with balls and some mats of some sorts rather than sand/gravel.

I will upgrade the outlet to 38mm+. I had a bit of a brainwave last night. I think I’m going to run a pipe from the outlet to the pond with a branch off to the waterfall controlled by a valve the filter is going to be boxed in a wooden box with a lid and side door.

thanks J.W

 

[addy1]

Welcome to our group! Nice write up of your pond

 

[GBBUDD]

at one time or another i have had just about every type of filter out there. I now have bogs and hands down they are my favorite. Crystal clear water and polished