Blowers, Air Pumps and Compressors

    This page contains background material on many terms you will encouter when choosing between blowers, air pumps, and compressors for your system.  You may also click on any of the following terms to get descriptions of each:  blower, air pump, and compressor.

       OIL-LESS AIR  COMPRESSORS. The primary difference between  the names blowers, air pumps and compressors is the pressure to  which they can compress air. All air compressors used for aquaculture purposes should be "oil-less".

        AIR PRESSURE. First determine the pressure required. To form bubbles you must  have enough pressure to overcome the water pressure at the diffuser's depth, the piping friction loss and the diffuser's resistance to air flow. Here is an example: With a water depth of  36 inches, a low-restriction piping system, say 4 inches H2O and a low-resistance air diffuser, say 10 inches H2O (just prior to cleaning). You will need air pressure of at least 50 inches H2O.  This is equal to about 2 psi.  Regenerative blower type compressors are preferred in the aquaculture industry because they are the most reliable and economical in this pressure range.

       AIR VOLUME. Your next consideration is the volume of the air needed to accomplish the job. If you have only one fish room for example,  you may want one linear air pump compressor with an additional one for emergency back up. In a larger facility, you might want two or more primary blower compressors and one emergency back up.

       AIR FLOW. When  using low pressure air, it's important that the air piping system and diffuser offer little resistance to air flow.

      SPECIAL  SITUATIONS. If you must go deep under the water or  use a high-resistance diffuser, you'll need to look at higher pressure compressors.

      Key Terms:     cfm - cubic feet per minute
                               psi - pounds per square inch (the higher the pressure in the system, the
                                        lower the flow - cfm - will be)
                               diffuser - attachment to air lines which emits extremely fine air bubbles into
    `                                    the water increasing the surface area of the air bubbles, which
                                         increases the amount of air diffused into the water

     A manifold with four diffusers



        Blowers are designed to provide large volumes of air at low  pressures (less than 4 psi) and are most commonly used in  conjunction with air diffusers and air lifts. This combination  adds oxygen and removes CO2 with  low power consumption. Typical applications include recirculating  fish systems, bait and lobster holding facilities, and shallow  pond aeration.

Return to Top

Air Pumps
     Fractional horsepower linear compressors fill  the gap between aquarium air pumps and blowers. Units supply up to  4.8 cfm and can push down to 10 feet. Many are outdoor rated, increasing their range of use.  These fit perfectly in applications such as Koi ponds, bait shop tanks, classrooms, laboratories, etc.

Return to Top

     Oil-less rotary vane and piston compressors are  the tool to use where depths are greater than 8 feet such as lake aeration, algae culture and lobster pounds. These compressors allow airlines to be run thousands of feet when electricity is not  near the water body. As little as a ¾ hp compressor can be  used to aerate and destratify a eutrophic 10 acre lake.

Return to Top

Return to Startup page