Well pressure tank replacement - galvanised or steel bladder??

[Momo99]

Hi, apologies in advance from this newbie with zero knowledge of the subject! We have an old rural property with a well as our only water source. The property used to be a working farm and had big sheds of ducks and pigs. It is now being used as a two generation home, so 2 kitchens, 2 washing machines, 4 toilets. We may convert in a few years and add a unit to rent out or add a couple of guest rooms to rent out. Currently there is a big galvanised pressure tank, its 1000L so thats about 265 US gallons I think. It has a hole in it, on the seam, we cannot get it fixed so need to replace. I am getting contradictory advice from various sources. One says replace like with like and get a 1000L galvanised tank (no bladder) and others say get a steel bladder tank 500L is big enough. We are going to get a new pump sized to fit the tank.
Our water is very hard, it corrodes everything and has a high iron content and we get a lot of sediment.
I would really appreciate advice on which is best in this situation - type and size.
Thanks so much in advance.

 

[Bannerman]

As your water has iron and hardness issues, are there treatment methods planned or presently in-place to address those concerns?
I ask as sometimes, a pressure tank without a bladder or diaphragm is utilized to provide some initial oxidation of the iron by using the air trapped within the tank. If other iron reduction methods are used, then your options will be greater in which type of tank you choose.

I don't know the logistics due to your location but Valveman, a moderator on this forum developed a pump control system that will change how your pump and water system will operate. Valveman is often active on this forum early (in North America) each day so you may wish to message him to determine if his Cycle Stop Valve is available to you in France.

If interested, here is a link to the Cycle Stop Valve website which includes various videos that explain how a CSV will operate with your existing pump. When using a CSV, a large tank will not be required as a 4.5 or 10-gallon tank is usually appropriate for almost all residential applications such as yours.
https://cyclestopvalves.com/

 

[Sponsor]

 

[Momo99]

Thank you. Currently there is no treatment but we do intend to install treatment when we get around to renovating the house. We need to build a whole new tank/pump house (the one we currently have is just a shaky old wooden shed). It is a shame the tank couldnt last until we start the renovations but ... thats life!

 

[LLigetfa]

A hydro-pneumatic (HP) tank should have an airmaker system of snifter/bleeder/checkvalve along with an AVC to remove the excess air. If you switch over to a captive air tank, then you need to remove the airmaker components, some of which would be down in the well which requires lifting the pipe/pump. You can replace the galvanized HP tank with a composite tank and leave the airmaker in place.

If you opt to switch over to a captive air tank, I would suggest a diaphragm rather than a bladder. Diaphragm tanks are available in composite or metal.

 

[Valveman]

A 1000L tank only holds about 25oL of water. A 500L tank only holds 125L. Your water comes from the well and pump, not the tank. The pressure tank is only to keep the pump from cycling on and off too much. With a high iron content you either need to stay with the old style air over water tank, or you will have to filter the iron some other way. Mixing air with the water using those old style hydro-pneumatic style tanks is one way to help with the iron. But if you can handle the iron some other way a Cycle Stop Valve and a small diaphragm tank is all you need and would do a much better job at supplying all those different uses and flow rates of water.