Buyer's guide — control valves
Fleck water softener review:
the 5600SXT, and why the valve is the product
There is no such thing as a Fleck water softener — Fleck makes the control valve, and somebody else builds the system around it. Once you understand that, the whole category gets cheaper and easier to shop.
By Tim Parker — Reads the spec sheets and prices the full install
Here is the thing nobody tells first-time buyers: Fleck does not make water softeners. Fleck makes the valve on top of one. A complete system is a Fleck valve bolted to a resin tank, filled with resin, plumbed to a brine tank. Different sellers assemble those same parts and sell them at different prices.
That single fact is worth money to you. You are not buying a sealed appliance where the badge determines the quality — you are buying components, each of which can be priced, compared and replaced on its own. It is the opposite of the dealer-quoted model, where you cannot see any of the parts or the price.
Why the 5600SXT is still the default recommendation
The 5600SXT is the valve water treatment forums send newcomers to, and the reason is unglamorous: it is metered, widely stocked, and repairable.
- Metered, not timed. It regenerates on actual water used rather than on a clock, so it does not dump salt and water on a schedule while you are away.
- Parts are everywhere. A failure in year eight is a part swap, not a new system. That is the whole argument.
- Every pro recognises it. You are never explaining your equipment to a plumber who has not seen one.
Newer valves add app connectivity and finer programming. Those are real features, but they are not why this valve has lasted. A device that runs unattended for a decade should be boring.
Fleck vs Clack: the honest comparison
Ask a water treatment professional and many will tell you Clack is the better valve. They may well be right. But the comparison a homeowner actually faces is not engineering — it is availability. Several Clack sellers supply only licensed plumbers or authorised water treatment businesses; Fleck is freely sold to consumers. So unless you are working through a professional installer who sources Clack for you, the practical choice is between a valve you can buy and one you cannot. That is why Fleck dominates the DIY end of this category and always has.
Buying one without a dealer
Because the valve is a component, the thing you are really choosing is the builder — who paired it with what resin, what tank size, and what support. Two things to check on any listing: the grain capacity (which must match your measured hardness and household size) and the resin cross-link percentage, where 10% outlasts the standard 8%.
On a well, do not buy the softener first — iron fouls resin and will shorten the life of any valve, Fleck included. Read why iron decides the pick on well water before sizing anything. For city water, our scored picks across the category sit in the best water softener guide, and installation costs are the half that never appears on the listing.