The Plant Filter
I added the plant filter to get more water volume because 4 goldies in the 55 was pushing it in terms of nitrAte production and I wasn't going to starve them to make keeping their water happy easier. The extra plants should also help suck up nitrAtes, but it's hard to tell how much. I hope it'll get better over time as the plants take hold. Since I'm running it on an opposite light schedule from the goldie tank, it moderates the pH swing you'd get with lots of plants--the tank with the lights off is serving as a CO2 generator for the tank with the lights on.
Here's the plant filter on 11/21/04. I built it on 9/5/04. Built a plant basket that runs the length of the tub using craft mesh. Unpotted one of my peace lilly plants and rinsed the roots well to remove the soil and added those to the basket. Also cut some runners from the pothos plant and added them for emergent growth. The lamp holds 150 watts 5000K and 75 watts 6500K compact fluorescent light. The ugly plywood under it is to elevate the tub to help with waterflow back to the goldie tank.
I used a rubbermaid tub that holds about 25 gallons of water and used 3/4" pvc pipe to connect it up with the goldie tank. I used a powerhead to pump the water to the plant filter and gravity drains the water back to the goldie tank. The blue piece is a one-way valve to prevent backflow as the pipe pushing water to the plant filter is set lower in the side of the tub than is the drain pipe. I had to be careful to make sure I couldn't have any floods or totally drain the goldie tank. I have the powerhead that's pumping the water to the plant filter situated at the top of the goldie tank so it can only lower the water line in the goldie tank no more than 3 inches and won't drain the goldie tank if something did happen to stop up the return from the plant filter. I used craft mesh to build a cover for the return tube, so nothing can get in and stop it up. I also keep the water line in both the goldie tank and the plant filter low enough to where there is leeway, so I shouldn't have any floods even if the power goes off.
Here's a couple of pics of the plumbing.
Here are the plants. I just added the water hyacinth (11/22/04).
The plant filter has pothos, peace lillies, duckweed, frogbit, salvenia, and water hyacinth growing emergent and bunches of submerged plants along with ramshorn and pond snails to help with any debris from the plants. I harvest a couple of tablespoons of the floaters to feed to the goldies daily.
Here are the plants (1/13/05). I've added more pothos and another peace lilly.
The plants are very happy! (3/29/05)
I recently bought a new 400 gph mag drive pump and replumbed it. The pump's now in the plant filter instead of the goldie tank. Here's part of the plumbing. The black 3/4 inch flexible hose is the intake for the pump. The intake strainer is in the corner of the goldie tank. Water is pumped thru a one way valve to a bulkhead on the side of the plant filter. The white 1.5 inch pvc near the back takes water from the plant filter back to the far end of the goldie tank (by gravity). Here's a pic of some of the plumbing.
Built a Trickle Tower filter. (5/22/05)
Added more peace lillies. (6/11/05)
and here's the new plumbing
The large white piece of pvc drains water from the plant filter back to the goldie tank. I adjust how high it is to control the level of water in the plant filter and goldie tank. I keep it up high when I first fill the tank after a partial water change to overfill the plant filter, cuz there's quite a bit of evaporation during the course of the week. later in the week, I'll lower it to let more water get back to the goldie tank to equalize the water level cuz of evaporation.