Gravel Filter conversion

[JohanKotze]

Good day, I am new to this forum. I have my pond for awhile now. My current filter is a gravel filter 1.9m (L) x 500mm (W) x 450 (D). The pond volume is 3700L. I want to build 3 chambers in the filter so the water flows through chambers from the bottom up. As my filter is above the pond water level, I can't use a SC. I use a 5500LPH pump that fed the current filter.

So all the chambers will have a crate at the bottom and waste pipes. The chambers will then be filled with gravel again but only the first chamber will be fed by the pump. The water will rise from the bottom and at the flows into 110mm down pipe and rise from bottom of the second filter, the same with chamber 3.

Will this concept work. Attached please find my current filter in question.

Regards
Johan

 

[addy1]

Welcome to our forum!

Water will flow up through the gravel, the question is will it flow up fast enough to compensate for the flow into the chamber. Since it won't be under pressure i.e. pumped up through the gravel.

 

[Lisak1]

Welcome @JohanKotze !

Your design, if I have the idea correct, could be described as three gravel bogs stacked one on top of the other. My question for you would be why three chambers? Why not one like the traditional constructed wetland filter bog that many here are using with good results? (And I'm not sure what an SC is?)

 

[JohanKotze]

Thanks for the quick reply. My bog filter is not stack but one filter. I see some partials in the pond I want to get rid off. I try to polish my water. I know the koi don't mind it but would like water to be clear.

 

[Lisak1]

So why would stacking the bog make that happen? You may want to consider adding a finer filter material to your skimmer box (if you have one) to catch the fine particles. Your bog filter is best suited for biological filtration, not mechanical.

 

[j.w]

@JohanKotze
Pretty set up you have there!

 

[JohanKotze]

Thanks J. W

 

[JohanKotze]

Hi Lisa it's not n stack bog filter but one level. No skimmer, think it will be my project.

 

[GBBUDD]

It seems the other side of the pond they had the Cadillac set ups like nexus but big bucks. then they have the three barrels one to collect heavy solids with brushed or sponges the second to have weir filters like a pleated micron filter and the third being micro beads for bacteria to grow on with lots of 02. The only thing that i see as missing is the plant roots to absorb and convert less desirable compounds. Mother nature when you work with her give her the opportunity to take over can out source anything man can develop with a whole lot less effort. It may require a lot more room but pound for pound she is amazingly effective. i have seen several such barrel filters online that seemed well built. But i have seen a couple of those switch over to building a bog. That is one of the things that sold me on a bog i didn't see one bog owner switch over to a mechanical filter.

 

[JohanKotze]

Yes, I must give mother nature time to develop a good filtration system. I think I am fiddling to much with my bog filter. I also think my plants are not planted deep enough or I have the wrong plants in my filter.

 

[Nevermore44]

Nice looking setup! Being a 3700L/975g pond and having some decent sized koi in there, your filtering just can't keep up with the daily input of food to the koi. The bog filters I see that work for people are much larger vs the size of the pond, fish load, and how often the fish are fed. I have a 1000g pond with fed koi and I ended up setting up a sand and gravel filter. It cleared the water of all green in a few hours that first day and has been working well ever since. Your pond area is nice and clean looking so you could always pipe this type of filter farther away to hide it since it's returns via gravity. They definitely aren't as nice looking as planted bog filter but they work well.

 

[JohanKotze]

Thank you Nevermore44, can you post some pictures of your sand and gravel filter and how you filled it with the sand and gravel. I have two bog filters and a shower filter.

I am busy installing a 15000L pump with a non return valve that will fed the 2 bog filters.

I all so is thinking about to change one bog filter, the bigger one, into a sand and gravel filter but can't get my head around the layout inside the bog filter. I thought of 3 chambers where water will be fed to 1st chamber, no media, and then flow through the other 2 and back to the pond. Chamber 2 will contain of larger gravel and chamber 3 with small gravel. Each chamber will have a waste valve. But I am not sure if this will work.

 

[GBBUDD]

I would look at placing a bog running along your fence it appears it could be about 12' long and it could be close to 24" wide? That would appear to at least double the amount of bog that you have. run some 3/4" marine ply up the fence to your desired height i'd lean toward 24" or more wrap the rubber across the bottom and on the outside edge i would make as thin but strong a wall as i could. 4" wall with rebar? there won't be a hole lot of pressure but i like to build things to last. and it appears you have Papyrus already or Egyptian palm i would line it with the papyrus but beware it grows a very dence steel wool like root system and you will want to leave your self plenty of room for the plants to grow up and water level raise as the roots restrict the flow... I too am using a bog, no mechanical filters and there is no way the water could be any clearer.

 

[GBBUDD]

An other option is to build what I said above and then build a send if not a third one above the other and completely hide the fence . there's something similar to what I am thinking in one of the Brazil you tubes below links garden talk . some pretty amazing pond builds.

 

[Nevermore44]

A multi tiers bog would be cool looking!

it’s called a sand and gravel filter... though really it uses varies sizes of stone and gravel. I used the standard “Birdman sand and gravel” plans. Here are my plans