The pump you choose is critical. Harbor freight sells cheap pumps, but you will be caught with a dead pump sooner or later if you use these (not to mention the lead and oil in your aquaponics system). What are some good pump choices?
As we learn about pumps, there are a couple of words that we need to define:
- Head Height
- This is the distance the pump must lift the water. Horizontal water movement only has pipe friction, which is not usually very much. A pump that is rated at 580 GPH at 5′ means that it can lift 580 GPH 5′. It can probably pump much more at 3 feet head height.
- How many Gallons Per Hour can the pump do? If you have your system on a timer, you will need to have the pump cycle your entire aquaponics tank about once an hour. As an example, a 300 gallon tank that is off for 45 minutes and on for 15 minutes will need to do (15 minutes goes into 1 hour, 4 times. 4x 300gallons = 1200gallons). Note that it needs to do this volume at the proper head height, and you should have a little extra to account for pipe friction, and pump gunk performance loss. So, in the above example, I would want a 1500 GPH pump to cycle my 300 gallon tank if I only ran it for 15 minutes of every hour.
- A 200 watt pump that runs 24 hours a day will cost you about $20 a month in electricity. It will also take almost 5 solar panels to run (assuming 45W per solar panel). Watts is a measure of how much power you will need. Two similar pumps might be $30 difference in price, but one could save you $200 a year in energy costs because it is more efficient. Generally, a 220V pump will require less wattage than a 110V pump too. There are other factors that MIGHT be important, such as starting watts vs running watts. Typically a pump requires about 50% more power to start than to run. This can be fixed by adding capacitors to fire more energy into the pump at startup.
- This is how high the pump will go before it stops pumping. Keep in mind that if you use a sump and then try to lift water above ground 5′, you will also have to lift the water from the sump (typically 2 or 3 feet), for a total of 7 or 8 feet. Some pumps drastically lose their GPH rating as the head height rises!
- There is a sludge/film that gorws on everything in an aquaponics system. This is normal, but you have to account for it causing more friction in your pipes and if you don’t clean your pump, ever, seizing your pump. If you clean the pump once a month that’s fine, and blasting water through your pipes once a month will also help. Be careful of blasting too much chlorinated water!
- Mag Drive
- Instead of having parts that are exposed to the gunk, a mag drive is built in a way that there are less moving parts and friction. The pumps last longer and are less susceptible to gunk build up.
Now that we know the basics of pumps, let’s look at some of the choices by pondmaster (the brand I use). If you know how big your tanks are, you can estimate a pump that is what you need for your system.
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Other pumps that had good recommendations as I researched:
- Danner (mag-drive only)/Pondmaster Manufacturer
- Rio (though not recommended for start and stop use like a timer)
I went with pondmaster because of the following reasons:
- 5 year warranty / Respected Brand
- Mag Drive
- Fish/Food Safe
- Nice Energy to Output ratio
- Ability to reliably pump pond water
Tips for Keeping Your Pump Cleaner
There are many configurations for setting up an aquaponics system. I have found that if you have a clean sump, your pump stays cleaner for a longer period. You also don’t have to worry about fish getting sucked up into the pump this way. 500 Gallon Aquaponics System that uses a sump to pump clean water after it passes through a variety of filters. Gravity moves the “dirty” water.
Once a month or so you can keep the pump running at full capacity by spraying it with high pressure water. This removes the gunk.
What would you do if your aquaponics pump failed Sunday night at 10pm? There are no stores open, and your fish will need to survive until you can get water/air flowing again. Without air, your fish might last 30 minutes. Without clean water flowing they might last for a few hours. For this reason, it’s a good idea to have an air stone backup and a second pump on standby that you can simply hot swap.
Most deep cycle batteries will only last about 12 hours if you have a 2 Amp pump. There are switches and relays that are normally open, but that fail closed in the event of a power loss. The bad news: a deep cycle battery worth having is going to cost about $250. Solar panels (to match your pump wattage), and an inverter will get you through the day, but a simple setup to run your pumps is also going to cost around $400 (before the battery). You would still need the battery for night time or cloudy operation. To be safe, you might even need 2 batteries.
Harbor Freight Aquaponics Pumps
I purchased a pump from harbor freight and it leaked oil (I cleaned this up and started over). The instructions said “contains lead”. After a few months the pump burned up and leaked more oil. However, it was the cheapest! (buyer beware)