There are a couple of different in well pressure tanks. One is made by In Well Tech out of Wisconsin. The other is made by H2Optimal out of Nebraska and is called a Pitless Module. Neither tank is large enough to be of any good (3/4 gallon draw down) without a Cycle Stop Valve.
Some people have used them with the variable speed pumps but, since these pumps have little or no difference in pressure between on and off of the pump, these small tanks do not deliver even a cup of draw down. This causes the pump to start for every glass of water, ice maker filling, or wash of a tooth brush. A dripping faucet or leaky toilet can cause the pump to cycle or ramp up and down, hundreds of times per day. Of course it doesn’t help to use a larger tank either, as the variable speed pump tries to hold a single set pressure, and will still cycle for every glass of water. The temperamental and undependable nature of variable speed pumps is only exacerbated by the addition of an in well tank.
When used with a Cycle Stop Valve, these in well tanks will deliver the full 3/4 gallon of draw down because we still have a 30/50 or a 40/60 bandwidth in the pressure switch. The Cycle Stop Valve holds the pressure in the middle of the pressure bandwidth as long as at least 1 GPM is being used. This eliminates so many cycles for the longer term uses of water, that it may no longer be a problem for the pump to cycle on every time the toilet is flushed. The 3/4 gallon draw down will at least let you get a glass of water, wash a tooth brush, ice maker fill, or use less than 3/4 of a gallon of water without the pump having to restart. At the very least these tanks allow you the convenience of putting all the controls in the well. You can always add more draw down to the system by installing an additional small tank under a sink, crawl space, etc. if needed.
Without the CSV, these small tanks would quickly destroy a pump from hundreds of rapid cycles per day, even with a wide band in the pressure switch. Cycle Stop Valves, Inc. actually wrote and holds the patent on the in well tank and control valve combination, as again that is the only way these tanks are large enough to operate a home water system.
As of November 2nd 2006, In Well Technologies of Wisconsin no longer has a license from Cycle Stop Valves to use this patented idea with any valve. There have been numerous problems with these tanks holding their air charge. As they are very small tanks to start with, they do not hold very much air. It is imperative that this small amount of air not be able to escape, or the tank becomes waterlogged and destroys the pump. This has happened with the In Well tank so many times, that Cycle Stop Valves no longer wishes to be associated with this brand tank. Use of this tank with a CSV or any other valve is no longer covered by license.
The Pitless Unit from H2Optimal uses a larger casing above the pitless adapter, that will accommodate a small standard type bladder tank. These type tanks are proven to hold their air charge, and H2Optimal is working under license from Cycle Stop Valves patent. They can be seen at pitlessunit.com.