Once you have purchased your hot tub or pool, you want to enjoy it for many years to come. If you stay on top of the small amount of maintenance that is required, you should have no trouble with them, and they'll provide you with many years of enjoyment.
There are a few chemicals that you will want to use to keep the water in pristine condition. All water is not the same and in some parts of England the water can be extremely hard. If you aren't sure about this just look at your washing machine or shower head and see if you can detect any white flakes forming. If so, this means you have hard water and what you are seeing is a calcium build up.
This type of water is also going to affect the performance of your hot tub or pool if you don't add some stain and scale inhibitor to it on occasion. If you don't do this and the hot tub begins to build up calcium, it can affect the heater and pumps, and the water flow for your hot tub or pool.
To make sure that you stay on top of this and that your water is not containing too much calcium, you can test it. This is something you should do each time you top up the hot tub or pool. There are various testing kits available for this and there are different brands of stain and scale inhibitors.
You may be thinking that you should fill your hot tub or pool with soft water, so you won't have to deal with this problem. This is not a solution either because too low of a calcium level can lead to corrosion, which is another big problem in itself.
Ideally, the right calcium level should be between 100-200mg/l. The testing kit you are using should provide you with a chart that shows you the various readings and what they mean. If the calcium level is high, you should use a stain and scale inhibitor. On the other hand, if it is low, you will need to add a calcium hardener.
One of the signs that the calcium levels may be too high is the water has a cloudy look to it. Testing is the surest way of knowing exactly what you are dealing with when it comes to calcium.