Huge botanical filter: How would you make this work?

[WhistlingBadger32 14]

I'm just doing a little thought experiment here, designing a gigantic (maybe 500g or so) native fish tank in my head for a local business. A mountain stream, high water flow, lots of hard scape but few or no aquatic plants. Since I tend to think plants make the best filters, I am envisioning a huge botanical filter along the back of the tank: A tub or trough of some sort with coarse gravel, loaded with native riparian plants (dwarf cattail, sedges, dwarf willow, geranium, blue flag iris, etc). Water flows out of the main tank, through the gravel and all the plant roots, and back into the tank. I envision this gravel trough along the back/top of the main tank so it gives a nice, natural look of riparian vegetation growing on the side of a stream.

Has anyone ever tried (or observed anyone else to try) something like this? How does it work? My big concern, besides the weight and difficulty of building the thing, would be that the gravel will get clogged up with mulm over time, and I don't think there would be an easy way to flush it out. So a gigantic canister filter would probably be much more practical. Other than that, I am very fond of the idea. Thoughts?

 

[Rusty_Shackleford35 150]

I would look into a Netlea prefilter. When they are full of appropriate foam they will scrub the water of debris just like a 50 micron sock.

 

[TwoTankAmin30]

Probably your best bet would be a sump system. The problem with a veggie filter is the space needed for it. Consider how many plants you would have in he tank if you were able to go that route. then consider how big a tank you would need to hold just them so it would be your primary filter.

I had put together a plan for a 125 gal. tank using a sump. But mine was to be filled only with Poret foam. My goal in choosing this was because I wanted more gallons of water involved with the system. So I had a 40 gal, long to be the sump. I had the tanks, the Poret sheets and an Eshopps overflow and the needed pumps. But life has a way of changing our plans. I ended up having to move the fish planned for the 125 into the 150 when the 75 gal, the fish were in sprung a leak. So I never set up the sump system.

One of the appeals of sing Poret sheets was that it made it easy to remove one sheet to clean it when needed without having to stop or pull apart the sump to do this. The plans was to have several 3 inch thick foam sheets starting with a single 10 ppi, then 2 or 3 x 20 ppi and ending with a 30. I had worked with Dr. Tanner of Swiss Tropicals on the design.

If you don't want to do a sump filter, you night want to investigate using two massive Poret corner filters. Have a look here:
https://www.swisstropicals.com/filtration-shop/cornerfilter-shop/
I would for sure contact Dr. Tanner and ask for his suggestions for filtering the planned tank using Poret foam. Not only is Poret one of the better biomedia I have seen, it is also excellent for mechanical as well.

Of course of you go the sump route, it would be too small and need less overhead room for a decent plant load.

 

[Archerfish]

@WhistlingBadger, what you describe is a bog or wetland filter. They really work for our ponds and there is no reason you couldn't make it work for a large aquarium.

 

[GaryE]

I knew a guy in Texas who had mangroves in a large greenhouse. Scale in winter seems like the issue to me. Artificial light, spaces heated well enough for plant growth (but plants that thrive year round in the temperatures a mountain stream North American tank would need in winter - 4c?).,, I dunno.

 

[CassCats11]

I do this with my 135g. Since goldfish often eat plants, the crypts and anubias that they don't eat are not enough for nitrate control, so I do riparian plants in the plant pot pumps Ive made as filters.

Of course since this pic, it has grown chaotic and needs trimming that I just haven't been bothered to do yet this month lol

I do pothos, bacopa monnieri, zebra plant, rubber plant, and there's a spider plant hidden in the mess somewhere.

Filters are stuffed with sponge, floss, and ceramic media. I vacuum them out to clean them. I use internal pumps inside the tanks to push water into the window planter pots, which then drain out of another set of pipes into the tank. The outlet tube is lower than the intake part, so it does not overflow easily. Aquarium sealant is used where the tubing is attached to the window pots.


You could do multiple large basins to do this, above the tank, such as water troughs or plastic washing basins as long as you have the support for their filled weight considered. Those can provide refuges for the plants you want to use as filtration purposes easily.