My system currently has a 330 gallon in ground fish tank that started life as a hot tub. There are two pumps in the tank, one small one, 264 gpm, always on for aeration and a 1400 gpm pump that is on a timer for 15 minutes every two hours. The output from the larger pump is split in two and delivered to each end of the adjacent raised brick planter box, converted by lining with EDPM and filled with pea gravel. The measurements of this bed are approximately 16' x 2' x 2'. There is a small pump in the center of this bed to return the water to the tank that is timed to start at the same time as the large pump in the tank and continues for 30 minutes. This is in the fenced front yard of my house in Tempe.
I started this system the end of last October. First fish in were 40 Rosy Red Minnows. Several weeks later, I got about 10 Tilapia free from a man who had used them to cycle an indoor aquarium. Over the winter, the fish tank was covered with repurposed double pane sliding doors and heated at night when it was so cold.
The fish are thriving and reproducing and the vegetable and herb plants in the bed are finally flourishing.
I'd love to know what others here are doing!
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Very interesting setup, Lisette. I am still in the "I want to do something" stage so all shared information is really appreciated. I echo Cindy's question - why 2 pumps?
Good luck, please share more as you care to. Thank you for sharing.
I'm saving up to build my pond. Some questions for you.
How do you manage algae with your pond being in full sunlight?
What type of heater did you use in the winter?
Why did you decide on two pumps as opposed to one?
Do you add bacteria for maintenance and if so, what kind?
I'll try, but keep in mind I'm still learning!
Algae - Early on, the water was often very green from floating algae. Now with the bacteria and oxygen (guessing here) in better balance, the water is quite clear. I'm adding a small amount, 2 tsps, of rabbit manure to the pond to encourage the plants. (If I put it directly into the bed, my 3 dogs would harvest the manure.) The algae on the sides is fish food or decoration depending on how you look at it.
I will work on answering the other questions soon
More Algae - The filters on the two pumps in the pond need cleaning about every two days as they clog up fast. The filter on the pump in the bed almost never clogs, since the water has gone through the pea gravel first.
Pumps - Well, three pumps actually, but I'm glad you asked because it is making me rethink. One small pump is on continuously as a fountain in the pond for aeration. One big pump in the pond is on for 15 minutes every 2 hours. I was trying to approach turning over the volume of the pond in 15 minutes. The recommendation I found said to do this every hour, but it seems to be working well now. The third small pump is in the raised bed and goes for 30 minutes every two hours. Now, I'm wondering about using the pump in the bed that never clogs for aeration, by changing the water return to above surface rather than below as it is now. Would that give the fish enough air? What about switching the big pump to 15min/hour and the small bed pump to 30min/hr and eliminate the fountain pump in the pond. How much more electricity would that use? See why I call it an experiment?
Heater - grabbed the biggest one I could find in the Pet store when we were having those freezes last winter. I should check and see if a pond heater or stock tank de-icer might be cheaper to run.
Bacteria - I started the pond with about 40 rosy red minnows, cheap feeder fish, cost about $5. They were the initial source for bacteria. The plants in the bed did not do well for the first several months, perhaps because the bacteria needed to build up? Though also probably because I didn't have the cycle schedule right.
Folks are always welcome to come see the experiment.
Cleaning filters every two days is pretty high maintenance... I am cleaning about 3 weeks during the summer months and 6-8 weeks during the winter. I am working on a design where I can cut that in half. (Disclaimer: I am not raising for food, and I use some chemicals.)
I'm no expert, but this is my experience. Feeder fish won't add enough bacteria with our climate, I have to keep adding bacteria every week, particularly as water temp goes over 90 degrees. I wonder if I'm throwing my money away when it's that hot though. Things that help to keep algae down: keep water surface moving as much as possible, shade in summer months, barley pellets in filter (can get pricey though). I don't have a fountain, but some do. The other issue is wear and tear on your pumps. I get about a year out of a pump, admittedly I buy cheaper pumps.
I'd love to come see your setup. I enjoyed looking at your pics.