How often should spa water be changed?

PSC Ep. 82: How often should I drain my spa and add fresh water?

In today’s episode of Poolside Chat, Rob and Matt tackle another common swimming pool question: 

How often should I drain my spa and add fresh water?

The main reason you would want to drain your spa is that it can get pretty nasty. The spa is a small body of body of water, consider some of the things it collects during use, think about dead skin, natural body oils and 💩. Over time water becomes so saturated with chemical buildup that it gets harder to balance. Water will start to get cloudy, and the telltale scum line will appear..

Usually, you want to drain and fill the spa every three to four months. That’s going to change depending on the usage of the spa. If you use the spa more, the periods between draining will likely be shorter than if you only use it a couple of times a month. Measuring the spa’s Total Dissolved Solids (TDS) levels is the more precise of determining when to start anew. Take an initial reading directly after refilling and balancing your water, then test semimonthly.  When your TDS level reaches 1,500 parts per million above the initial test result, is when you want to drain and refill. Let’s say it starts at 1,500. Once it raises to 3,000 parts per million, you go ahead and drain it and refill.

Some things you can do to lengthen the time period between refills are: add an ozonator, which has no by-product or add mineral cartridge, and you definitely want to oxidize it every time you use the spa. After you’re done, go ahead and shock it with a non-chlorine shock. That’ll lengthen the time in between having to drain it.

We also have a blog series that I wrote that discusses draining a spa and refilling it with freshwater then all the balancing that took place. Dirty Spa Draining and Refilling: Part 1 / Part 2 / Part 3

If you have any comments or questions about spa or pools, please leave a comment down below. Thank you for joining us, bye.


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One thought on “PSC Ep. 82: How often should I drain my spa and add fresh water?

  1. Hi… i recently purchased a variable speed pump. How ever, since doing so… my heat pump doesn’t seem to be working well with it. I think the heat pump requires higher rpm speed. Do you have any idea what the minimum rpm should be set at for the heatpump to work? Also how many hours should the variable speed pump be on for to have the pool maintain the ssme desired temperature?

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