Welcome and thanks for your firefighter service.
Good answers so far.
1. HiBlo pumps come in different models from lower cfm to higher cfm and higher psi(pressure); priced appropriately. HiBlo pumps run noticeably quiet due to design as linear diaphragm. They are rebuildable. IMO they are more for shallower ponds depending on psi of compressor.
The HiBlo200 Max Continous Operating Pressure: 4.3 PSI. IMO this means a maximum of 4psi X 2 = maximum air release of 8ft deep.
Deeper than 7-8ft likely unnecessarily strains most linear diaphragm pumps. Example 9 ft deep you need at least 4.5 psi for pump to release air at 9 ft deep. CFM is cubic feet per minute(air volume flow) and most diffusers require at least 0.5 to 1 cfm each head or membrane. Most pumps lose some air volume as the depth(psi) increases.
You want your pump to have at least 1/2 the psi of the depth of your diffuser. It is much better to have 1-2 extra psi because as the diffuser plugs up there is adequate psi available reserve to minimize excessive strain on the pump which does shorten the life span of the pump. Pumps are generally the most expensive part of the aeration system; protect them, value them, and properly size them to your needs, and they will serve you well.
For your pond depth(16-18ft) I prefer the rotary vane 1/4hp compressor(10psi continuous operation rating). This gives you a psi reserve of 1-2psi.
Most smaller ponds(0.2-2ac) will naturally mix down to a depth of 6ft, exceptions occur.
Despite what manufacturers claim all diffusers tend to clog up depending on water conditions; some clog faster than others. In my experience air stones clog faster and are harder to clean than smooth membrane diffusers. Rough surface diffusers provide lots of surface pores for accumulations of biological and mineral clogging growths. IMO all diffusers should be raised, examined, and cleaned EACH YEAR to get the best all around performance of pump and diffuser.
You can easily build your own aeration system from individual parts. There are numerous ways to save cost for DIY. It all depends on how fancy and convenient, easy, and time consuming you want it to be. Example - self weighted airline is the very best underwater BUT you can use good quality garden hose or black polyetheylene irrigation tubing (abt 0.10/ft). The tubing can be allowed to float or weighted with rebar, chain, stranded cable or even bricks. Bricks should be attached(wide banded) so they DO NOT KINK the airline which is esp important. Just as in water flow & fire hoses more flow usually requires larger diameter pipe when pressure is limiting. Smaller diameters require more psi which can strain the ability of the pump. For most small ponds I suggest 1/2"-5/8" ID air tubing for total runs of 80-300ft. For demonstration, I've used a good quality garden hose that floats as aeration airline going on 20yrs now. This saved a significant amount of money vs weighted airline.
Last edited by Bill Cody; 02/14/19 09:55 AM.
