Smart Aquaponics – defining the new system
So in my last post, I started describing the basics of controlling the flow of water in a complex aquaponics system. Here are some other constraints that I will be adding to my design.
- The design must get the best “bang” for the buck.
For the most part, I’m going to try to use inexpensive materials that are easy for me to acquire locally. For example, I don’t mind putting extra effort into cleaning up used IBCs if doing so saves a lot of money. As always, I’ll try to gauge my time against the cost of the item.
- The design must be power efficient
To accomplish this, I’ll be using a very efficient water pump that is always on. I am planning on using only one, high rate of flow pump. While it is possible to use several smaller pumps to more easily move the water around the system, this isn’t very efficient, and could lead to multiple points of failure. It is also possible to cycle the power on a pump to increase power efficiency, but in doing so the lifespan of the pump suffers. More reliable pumps and “soft start” pump controllers are more expensive. There may come a time when I rethink cycling the power on pumps, but first I’ll design a system that doesn’t require this.
- Shorter amounts of PVC pipe
The water will come into my system through city water, and it will either leave my aquaponics system through the city sewer, or be diverted to my lawn, flower beds and garden. I would prefer any water leaving the system go to my lawn or garden, but there may be times that I will want the used water to go directly to the city sewage treatment. I see this as several different PVC systems that include, 1) water delivery from the city to the system. 2) Water flushed from the system to the city sewer or to storage for lawn / garden. 3) Water delivered from the sump to the grow beds and to the fish tanks. 4) Water returning from the grow beds and fish tank to the sump.
I may make use of bridge siphons to connect parts of the system, and I will use flow restrictors for things like hanging towers of strawberries.
- Parts are easy to repair or replace
This means that anyplace I add a valve, pump, or other PVC connection, it should be installed in a manner that is easy to disconnect and replace with a new part. Valves should be easily repaired with standard tools.
- System must “fail safe”
If power goes out or the pump fails then the system should not flood at any point. Grow beds should drain completely, and fish tanks should stay full. If any valve fails in the open, or closed, position then the system must alarm, and the system must not lose water. There should be hooks built in for monitoring water levels and flow rate.
- System is easy to expand
If I want to add grow beds, fish tanks or sump tanks, it should only be a matter of space and a little extra plumbing.
- System is easy to clean
Solid waste should usually fall to an easily collected place. A standard pond vacuum cleaner should be able to reach all parts of the fish tanks. Grow beds should be easy to clean. This isn’t about bio filtration of waste – not yet.
Constraints are key to system design
I’ve read that any problem is easy to solve if there are no constraints to worry about. Sending a man to the Moon is relatively cheap and easy if you’re not worried about food, water, air, or an eventual return to Earth. It is constraints like this that define the challenge. And stating them clearly is a good way to start.
What must be understood is that at the start of a project, we really do not know what all the constraints might be. So I’ll be prepared to update this list.