How To Maintain Your Spa or Hot Tub

Below is the quick and easy approach to doing the chemicals of your spa. It is better to do the chemicals this way, than to try to do it perfectly, and screw it up.  If you get it perfect it won’t stay that way for long.  So do it my way and enjoy.   Keep It Simple.

Chemicals To Buy

  • Granular Chlorine (Sodium DiChlor) Buy the 2lb bottle with the lid the same diameter as the bottle. You will use the lid as a measuring cup. Any brand is fine.
  • Soda Ash This can be bought any way you like. Soda Ash is Sodium Carbonate. Baking Soda is Sodium BiCarbonate. Don’t buy Baking Soda, please.
  • Test Kit.You only need two testers in kit. Phenol Red for pH and OTO for chlorine.

This is How it is Done

  • Start with fresh water, by doing a drain, clean and refill of your tub. We don’t start any service without a complete drain, clean and refill of tub, neither should you. Clean the filter too.
  • Add chemicals – An average size spa of 4 to 6 people uses 1.5 caps of Soda Ash and 1/3 cap of DiChlor. If the spa is small (like 1 to 2 people) use a little less of each. If bigger use more.
  • Every time you use the spa, put in 1/3 cap of DiChlor in (average spa) before and after use. Add the chlorine with the jets running to help dissolve the granules. This way if you haven’t used spa for awhile there will be chlorine in the spa. After using the spa you will have depleted the chlorine level, so add 1/3 cap to keep spa nice till next use. Heat, Use, Sun, and Time all break down chlorine. Note: You can test the spa before and after use for the first 3 or 4 uses to see what you really need. You may need more or less of what I recommend. Keep spa at 3.0 to 5.0 for chlorine and 7.8 or above for pH. Different use patterns and size of spas effect chemicals. My amounts are pretty close for most situations. Testing for 3 or 4 uses will ensure more accurate amounts.
  • Test the water for chlorine and pH twice a month. Keep pH above 7.8 and chlorine around 3.0 to 5.0.
  • Change water every 3 months of regular use or once a year for occasional use. Best to change water every 20 hours of use. But this is harder to remember. I change my spa every 3 months no matter how often I use it. Fresh water is better than old water. Remember this is like a bath tub.

Note on Approximate Chemical usage of spa

  • 1/3 cap of chlorine before and after use for one person
  • 1/2 cap of chlorine before and after use for two person
  • 3/4 cap of chlorine before and after use for three person
  • 1 cap before and after use for many persons, plus add 1 cap every 15 min.

That’s It! That’s all you need to do.Note: If you don’t like the way the water is any time, just drain and refill. Don’t buy all those shocks, foam down, etc. Why bathe in all that stuff. Foam is caused by body oils, so drain with a sump pump for best results. This way you can flush the system and get the oils out.



Detailed Explanation. Read only if you want more info.

  1. You don’t have to buy lots of different chemicals. This causes lots of confusion. Also you bathe in these chemicals. Do you really want too. Keep it simple and you will do it regularly. Also less chance of mistakes. My method is 80% correct and it has worked for me and my customers for many years.
  2. If you do get the water perfectly balanced, it will not stay that way for long. Your body has a pH of 5.5. The pH of chemicals differ. DiChlor’s pH is 6 to 6.5. Every time you step in the tub the pH lowers and every time you use DiChlor the pH lowers. Low pH causes the metals in the tub to corrode, shortens the life of the spa cover, skin irritations and eye irritations can develop. This is why I like to run a high pH. pH of 8.0 is perfect. This has been proven to be the pH where the water is most comfortable for the user. My method runs the pH a little higher. By adding extra Soda Ash than what is needed we create a reservoir like of high pH to counter the low pH being added all the time. If you don’t add extra Soda Ash you will need to test and balance spa more often. You never need to add acid to a spa. Both Bromine and Chlorine have low pH’s. Chlorine works best at low pH’s like 7.2 to 7.6. This low pH is hard on a spa and you. Bromine works well at any pH However you can’t just instantly add Bromine and you need to use shock treatments at times. Keep with the Chlorine.
  3. If you have a good working ozonator then you can use very little chlorine. Ozone needs a tad of chlorine or bromine (about 1 oz to get the ozonation process started). You need to add this every now and then. I’d say about every 2 to 4 weeks and after any drain and fill. I only like the ozone units in spas that run a small pump 24/7 for heating, filtration and ozonation.
  4. The ozonator’s that run on a time clock are not worth much. Ozone lasts about 20 minutes in the water in ideal conditions. So you need 24/7 delivery to be effective and not use a lot of chlorine or bromine. What’s nice about ozone is that you do not add a lot of Chlorine, Bromine or Soda Ash. Just plain clean water. Ozone does take electricity though. Hot Springs, Dim One, Sundance are some of the tub manufacturers that offer this. Not on all models, so check. Again you want a 24/7 delivery of ozone.
  5. Your filter is your spas Kidney. So keep it clean. Replace every 1 or 2 years.

Try my method. I think life will be simpler for you. I also think you will enjoy your spa more. We service our monthly customers this way. I have not had one complaint on spa water, ever. Our customer base keeps growing and growing. So if you want to service your own spa try this.

Doug Moore