I wanted to share a success story after purchasing a larch wood-fired hot tub and finally finding a way to maintain the water successfully!
When I originally planned to buy the tub, I received a lot of advice warning me that wood hot tubs are notoriously difficult to maintain because wood is a delicate material that is easily damaged by oxidisers and can also destabilise your water chemistry due to tannins and other organic compounds. I was nearly put off, but stubbornly decided to give it a go.
The tub manufacturer advised against using chlorine and instead recommended an (expensive) MPS product with silver ions. I wasn't convinced about the efficacy of the product (especially when the tub water was cold) and a comment on this site encouraged me to try a low but consistent level of chlorine instead. I used dichlor granules and this kept the water in good condition for a couple of weeks at a time, but after that the combined chlorine levels started to rise. I wasn't comfortable shocking the water because of the potential damage to the wood, so I ended up changing the water pretty regularly.
After a while this started to get a bit tedious, so I invested in a UV light and sand filter that I run on a timer twice a day for 2 hours. I've been doing this for about a year now (while continuing to maintain FC at 1-3ppm) and it seems to be working very well. The wood is in great condition, the water is clear and sanitary (i do regular bacteria tests) and algae/mould seems under control (i change the water every couple of months and give the walls a quick soapy scrub too). I only use the tub every 2-3 weeks, so this method is perfect because I only need to check the levels every 4-5 days and it doesn't feel like too much work.
I hope this is of interest to anyone who might be considering a wood tub or currently struggling to maintain one.
When I originally planned to buy the tub, I received a lot of advice warning me that wood hot tubs are notoriously difficult to maintain because wood is a delicate material that is easily damaged by oxidisers and can also destabilise your water chemistry due to tannins and other organic compounds. I was nearly put off, but stubbornly decided to give it a go.
The tub manufacturer advised against using chlorine and instead recommended an (expensive) MPS product with silver ions. I wasn't convinced about the efficacy of the product (especially when the tub water was cold) and a comment on this site encouraged me to try a low but consistent level of chlorine instead. I used dichlor granules and this kept the water in good condition for a couple of weeks at a time, but after that the combined chlorine levels started to rise. I wasn't comfortable shocking the water because of the potential damage to the wood, so I ended up changing the water pretty regularly.
After a while this started to get a bit tedious, so I invested in a UV light and sand filter that I run on a timer twice a day for 2 hours. I've been doing this for about a year now (while continuing to maintain FC at 1-3ppm) and it seems to be working very well. The wood is in great condition, the water is clear and sanitary (i do regular bacteria tests) and algae/mould seems under control (i change the water every couple of months and give the walls a quick soapy scrub too). I only use the tub every 2-3 weeks, so this method is perfect because I only need to check the levels every 4-5 days and it doesn't feel like too much work.
I hope this is of interest to anyone who might be considering a wood tub or currently struggling to maintain one.
