Draining & Filling

Why, how and how often should you drain and refill your hot tub or spa.

Why do hot tubs and spas need to be drained and refilled?

Your spa has a filter and sanitising chemicals so why does it need to be emptied and refilled when a swimming pool doesn’t?

A spa contains a much smaller volume of water than a swimming pool and runs at a much warmer temperature but just as many people might spend just as much time in the water.

As people soak in the spa’s water, they release perspiration, body oils, deodorant, perfume… a whole host of things that dissolve into the water.

The chemicals, the filter and Sundance’s CLEARRAY UV treatment system will oxidise or remove a lot of those impurities, but not all of them.

Sticking to a good service routine, checking the pH and water balance will all go a long way to keeping your water clean and bright but eventually the deposits build up and the water has to be changed.

How often does a spa need to be drained?

How often you need to drain your spa will depend on how much use it gets.

There are sums and formulas to work this out but as a rule of thumb a typical family spa should be drained at least every three months.

You can get a TDS (Total Dissolved Solids) test strip from your spa shop which will give you a good indication or you should drain and refill when the water starts to become foamy, cloudy, you have difficulty maintaining pH or sanitiser levels or, of course, if there is a noticeable odour.

How do I go about draining and refilling my spa?

Draining your spa is easy and simple.

First of all turn the pump, thermostat and then the power off. Then simply attach a garden hose to the drain valve and run the hose to somewhere it will be safe to allow the water to drain away.

There are chemicals in the spa water so you really want to make sure that the water goes into the drainage system rather than just soaking into your lawn.

Once the drainage valve is open the spa will empty by gravity. A little bit of water may be left in the foot well but that only needs to be removed if you are putting the spa away for the winter.

To refill your spa just run the garden hose from the tap and fill to its normal operating level.

Once the spa is full, you need to prime the pump; that is, you need to get all of the air out of the system in order not to damage the pump or the heater when the spa starts operating normally again. Some spa pumps are self-priming, but always follow the instructions you received with your particular spa  for this vital stage.

Check and balance the fresh water for pH and calcium hardness and set the thermostat to bring your spa up to temperature