What You Should Know

What you should know

Before you buy a windmill aerator:

I’ve been assembling and selling windmill  aerators for many years and have become very familiar with the many choices available. As you know, it can be difficult and confusing to make a decision on what to spend your hard earned money on. I can help you to make that decision and AVOID UNSCRUPULOUS DEALERS by passing on the information I’ve gathered over the years.

The first thing you should know is what type of pump is on the WINDMILL AERATION SYSTEM you are considering to purchase. It is my opinion that the worst possible choice you can make is the bellows type pump or otherwise referred to as a bladder or air bag pump. The air bag in the bellows pump is often a Firestone or Good Year product. Bellows type pumps become very weak or stressed when the diffuser is submerged in more than 5 feet of water. This causes the bladder or air bag to very soon become fatigued (or worn out) and it can be difficult to change on top of a windmill and about $130.00 to replace. Some bellows pumps produce almost 5 cubic feet of air per minute (CFM) but only 2-3 pounds per square inch (PSI). You should only be at approximately 2.1 feet of depth for every (PSI). The 2-3 PSI
from the bellows type pump gives you a depth of 5 or 6 feet.

The pumping action on a bellows pump (air bag)  is intermittent with a burst of air then nothing, a burst of air, then nothing, making for very little water circulation. Your WINDMILL AERATION SHOULD BE PUMPING A STEADY CONTINUOUS FLOW of air from the diffuser at the bottom of the pond creating a column of air bubbles to the surface; this moves massive amounts of water from the bottom of the pond to the surface. I do not believe this is possible with a bellows type pump as you are limited to shallow depths and I believe the intermittent air flow produces very little, if any, momentum to cycle your pond water efficiently. Some dealers will tell you to suspend the diffuser at 2/3 of depth to avoid disturbing the thermocline, this should indicate a very limited depth due to insufficient PSI. Some dealers will tell you to put the diffuser to depths that will cause damage to bellows pumps just to make a sale. There are several different bellows pumps (airbag or bladder) on the market boasting of being 100% made in the USA, a 5,4,3,2,1 year warranty (only one year on the pump), pillow block bearings, and claiming to beat any price etc.. Some dealers put red tips on the blades and tail fin to resemble the old time farm windmill, you can do this yourself quite easily on any windmill. They do make nice yard ornaments and are nice for pumping up floating toys however I would not recommend the bellows pump windmill for any kind of aerating purpose. BE SURE TO ASK IF THE PUMP IS A BELLOWS PUNP,  or AIR BAG and if they say it is not then ask them to explain what type it is and get it in writing. Ask if the air flow is steady and continuous.

There are also some windmill aerators that use piston pumps claiming to produce very high pressure (PSI) and cubic feet per minute (CFM). You only need one (PSI) per 2.1 feet of depth so 10 (PSI) will get you down 21 feet and I have found 2 (CFM) to be substantial air flow. My experience with piston pump windmills is that they need higher winds to produce an adequate amount of air and crankcase oil can leave a film of oil on the water surface preventing oxygen transfer. This can be devastating to your pond and fish.


The most practical bearing in this type of application is a high quality sealed bearing that will keep the grease inside the bearing perfectly clean so you do not have to be climbing your wind tower to grease it routinely. Grease-able bearings are for tractors / machinery with high exposure to mud, dust and sand. that will cause premature bearing failure. This makes it necessary to keep greasing them on a routine schedule to push new clean grease in and the old dirty grease out. Grease-able bearings are inexpensive to replace but it is a dirty job you do not need. Sealed bearings are what you need on your windmill. The small amount of dust that may or may not be around your windmill cannot penetrate sealed bearings. SEALED BEARINGS give you long lasting maintenance free operation.


Another very important point to consider when you buy a windmill aerator is the tower assembly.

I believe four legged towers are an absolute must when high winds are prevalent in your area. Three legged towers are easily toppled over when wind force is applied to the side of one leg making the other two legs merely a pivot point to slam the windmill to the ground. This can be very costly to repair as I have found parts for three legged windmill aerators to be extremely expensive.

This is nice for the manufacture but bad for YOUR wallet. Windmills with four legs have been standing for over one hundred years.

Some towers have rolled edges making it much safer and less likely to cut your self. Others have extremely sharp edges and have cut many adults fingers to the bone. The manufacture can sell windmills with out rolled edges at a much lower price. This saves time and money for the manufacture but is very dangerous for children that might attempt to climb a tower with out rolled edges. Rolled edges make assembly and maintenance safe for you. BE SURE TO ASK IF THE TOWER HAS ROLLED EDGES!!


After you have read the above information you should be better informed to make purchase. We now have a product that is a combination of all the positive factors and less all the negative factors that have been mentioned above. It is Made in the U S. Our pump is a 10”diaphragm type pump with a ½” stroke that gives you the steady continuous flow needed. Our tower has four legs. Our blades are tapered at center and widen at the tip, this causes the rotor to start turning in lower winds and gives more torque. Our pump has a washable filter and high quality sealed bearings.


A Three year warranty is standard in the industry.

Always look for or ask about return policies and refunds. Windmills are usually shipped in several heavy packages that can get expensive to ship. If you end up with a bellows type windmill and decide to return it, some dealers have return policies that require as
much as a 20% restocking fee and customers are responsible for all shipping expenses. So if your windmill cost $100.00 to ship one way and you paid $1300.00 for the windmill, you are now out $460.00 if you are stuck with this type of return policy. The dealer still makes his money but you will be out yours!

I would think that any dealer with this return policy has had many issues with customers wanting to return a product they were quite unhappy with.
Most websites will have a page with return policies, read them and print it off before you buy. You can also ask for return policies in writing from the dealer.