Undergravel koi pond filter

[Dale Wiley]

We installed this pond this summer. It has an undergravel filter that keeps the water running crystal clear. There is a 2 inch concrete slab under the filter plates, with about 6 inches of # 8 filter gravel on top of it. The pump is in the bottom of the sump and draws from under the gravel, thusly filtering the water very well.

I have grown real tired of the AS systems that do not effectively filter when built to their specifications. We have retrofitted 3 of those types this year, increasing the pump size by about 3 times with fairly good results.

There are some things I would do differently, but the client was very "involved" in the "input" process on this job.:huh: :huh: :angry:

[Stonehenge]

That's a creative idea Dale.

That looks like 4" corrugated at the front of the pond - does that serve as some kind of pre-filter skimmer?

What are those filter plates made from? Can you post a link to the mfg of that? I'd be interested in more info.... :)

[Dale Wiley]

The filter plates are extruded plastic with some slits cut in. They are placed on top of 2 inches of concrete, and the sides motarted in. The tube is 10 inch ADS solid that goes throught the filter palts and drwas the water from underneath the filter plates after the water comes down through 6 inches of # 8 gravel.

The water runs real clear and the manufactuer says a cleaning of hte gravel once a year is all thats required. It's pretty clean now, and I can tell there is getting to be some buildup in the gravel, as the water in the sump is lower.

Now I posted the same picutre and all at http://www.koivet.com and those guys just fryed me. By they have legimate points that I have taken under consideration. I guess time will tell. We built it to manfactuers specs and design. I guarantee the construction, but not the concept, as I have not personally had enough experience with an under gravel fitler and those damned expensive koi.Time will tell I guess.

This is where the filter plates are. That is $ 575 my cost worth of filter plates down there with $ 416 worth of gravel. This is NOT an inexpensive system.

Miracle Koi Food (http://www.miraclekoifood.com)

[Stonehenge]

Dale - I'm not sure why they'd fry you or why it wouldn't work. It is essentially an identical system to what you'd find in a fish tank.

For my personal taste I'm not fond of being able to see that much of the liner (I'm sure most is covered after stone is placed), and I'd bet the fish people got on you for not providing any hiding places.

But it seems like a sound system, IMHO.

[Dale Wiley]

The manufactuer tells me that 2 levels of bacteria will start in the gravel coloum and clean the water.

The koi people claim there is no way to remove the solids and that will cause the bacteria to go anareobic, and the filter will not work.

The manufacuter who also makes a nifty cleaner, says BS. The koi people say I cannot pull 2750 gallons of water an hour throught those plates, but it has been doing that for over 10 weeks now. I oversized the pump, beause the client wanted a lot of noise from the water fall.

The stone is placed farther in at the request of the client and my encouragement to her after she said she wanted to be able to walk around it and her grandkids wanted to walk around it. I too prefer the stone farther out, but I was very concerned about liability here given the cleint and some of the things she said.

The pond is 28 inches deep with all the gravel in it. Deep enough for the fish to get away from herons and coons. We placed several stacks of cement building blocks in to place plant containers on, so there is some hiding places for the fish.

We did change the design of the water fall after this, because that one just did not work. I like them higher, but the client wanted that lower drop, and since she paid the tab, she got what she wanted.

I gues time will tell, but what I know now is I can stick a glass under the top water fall and it is as clear as it comes. The pond stays fairly clear, but the client constantly plays with it :angry: and changes things around.