A common misconception, sometimes found on money-saving forums, is that the only benefit of a twin tank water softener is that it can provide soft water 24 hours a day, which isn’t worth the extra cost, because with a basic, cheap, single tank softener, you only get hard water in the middle of the night - and who needs soft water in the middle of the night?
In this post, we explain that regenerating at night - whether they need to or not - means that these single tank water softeners will always be inefficient, wasting water and salt, and costing you money.
When to regenerate? A tricky decision for a single tank softener
All water softeners need to regenerate after they’ve softened a certain amount of water. A single tank softener can’t supply soft water while it’s regenerating, so it has to be set to regenerate at night, when you’re not using water.
You use a certain amount of water on a given day. What are the chances that this turns out to be exactly the amount of water that your softener can soften without regenerating? Pretty slim.
Vanishingly slim.
So, assuming you used less water than your softener could have handled, your softener is regenerating when it doesn’t need to. That’s a waste of water, and of salt, both of which you have to pay for.
If a single tank softener isn’t inefficient, you’re getting hard water
Of course, the alternative is that you used more water than your single tank water softener was expecting, in which case you’ve been getting hard water since whatever point in the day your softener ran out of capacity.
A single tank water softener has two settings for when it regenerates: too soon, or too late.
And if you go away for a few days, and forget to re-program your softener? It will dumbly carry on flushing your water and salt away down the drain for no reason.
Really, a single tank softener is like a toilet that flushes once every hour. Most of the time, you’ll just hear it flushing itself when there’s no need. And when it actually needs flushing? Well, you’ll just have to live with it until the next flush comes around.
Working around the problem
You’d be amazed at the complicated solutions that people come up with to work around this problem. Electronic timers. Different “modes”. Computers that try to predict how much water you’ll use the next day.
It seems clear to us here at Harvey’s that taking the problem away is a better idea than developing all sorts of ways round it.
A twin tank softener just works
It goes without saying that a twin tank softener doesn’t have these problems at all, because it can regenerate while it’s still working. When it’s softened all the water it can, it goes right ahead and regenerates there and then. Not too soon, and not too late. You don’t risk hard water getting into your system, and you don’t flush salt and water down the drain needlessly.
Fisher Wednesday, November 02, 2011
I have had a single tank softener for 11 years. It regenerates at night but only after it has softened a volume of water depending on the water hardness. So when we are on holiday the machine just does nothing. If we use a lot of water for whatever reason it will still only regenerate after the same volume has been through the tank.For the time it takes to regenerate, the tanks in the loft have enough in them to cover all our needs; I have about 2 cubic meters in the tanks. I can reset the regenerate volume by measuring the hardness and resetting the hardness on the machine. What decides on your machine when there is a need to regenerate?
Ben Saunders Wednesday, November 02, 2011
Just like your softener, our machine regenerates only after it has softened a volume of water depending on the water hardness. The key difference is that it doesn't have to wait until night time.
Consider the decision that your softener has to make in this situation: it has softened 80% of the water that it can, and it's the middle of the night. Should you regenerate, or not? If you do, you're wasting water and salt - there's another 20% of capacity that you're wasting. If you don't, you'll reach 100% during the next day, and the family will have hard water getting into their system.
A twin tank softener doesn't have to make this decision. When one of its cylinders reaches 100%, it regenerates, and the other carries on serving soft water.
I'd love to know what the make and model of your current softener is. This is relevant to your point about the loft tank: 2 cubic metres of soft water would indeed be enough to see you through a regeneration - but if your softener is one that allows hard water through while it's regenerating (and most of them do) then as soon as you use any soft water from the loft tank during regeneration, the softener will top it back up again, with hard water. This means that your tank is now full of a mixture of hard and soft water - and, as you can see in Harvey's demonstration video, it doesn't take much hard water to take away the benefits of soft water.
In short, our softeners work in much the same way as yours does - but being able to regenerate at any time makes ours less wasteful, and less likely to introduce any hard water into your system.