The need/desire for a carbon filter depends entirely on what you may wish to remove from your water. If you are concerned about purely a taste issue, a point-of-use filter is a better option than a whole-house carbon filter, particularly one that has been in service elsewhere, removed, stored, etc. Depending upon the amount of time and conditions of storage and the water in it, it could be contaminated with any number of things.

You city's water report indicates that you do have a small amount of iron and manganese. Theoretically, those will be oxidized by the chlorine the city ads and fall out of solution as small particulate. However, since chlorination rates can vary, we will need to assume they stay in the water in order to properly size the softener.

You estimated 75 gallons per person per day. Is this based on metered water usage, or is it just a guess? Typical water usage is closer to 60 gallons per person per day. If 75 g/p/d is accurate, you will land solidly in the 3 cuft (96k grains) softener size. If 60 is accurate, you could get away with a 2 cuft softener, but a 2.5 would be better. Your calculations came up with a smaller size because you did not take into account the fact that softener capacity is dependent upon salt dosage.

The following requirements are for an industry standard softener. If you are looking for a non-electronic softener, Kinetico offers the more reliable options at a premium price (and you would need to deal with a local Kinetico rep). Any decent softener vendor should be able to provide the following:

• High quality American or German made resin. This will provide a tight size distribution for optimal flow within the resin, longer resin life and more reliable, predictable water softening.

• It will be better for you to install your own resin - things shift during shipping.

• Since you have CITY WATER: 10% crosslinked resin. The oxidizers that city water treatment plants use, such as chlorine or chloramine, are harmful to softener resins. Higher crosslinking will resist chemical attack longer.

• Top basket. This serves two purposes. It sets up a proper water distribution during normal operation and prevents resin loss during backwash.

• Gravel underbed. The gravel underbed is there to set up proper flow patterns, improve backwash, keep the bottom basket in place, prevent basket failure, and prevent channeling. Many softener sales companies like to leave this out or sell softeners with a vortex system instead. Vortex systems weigh less than gravel so they cost less to ship. In addition, they are a more expensive item that adds profit for the softener salesperson, but provides no additional benefit to the homeowner . It simply adds another piece of equipment that can break.

• Fleck or Clack valves. These set the industry standard. Be aware that you will not be able to purchase Clack valves online. This is not a problem if you purchase locally.

• The valve should regen...