KOTO ELEMENTS RANGE - FAQ
WOOD FIRED HOT TUB - みず (MIZU)

What are the benefits of a wood fired hot tub compared to an electric hot tub?

Running costs, ease of transportation and heat-up times.
Eco Tubs are much more economical to both purchase and run.
Eco Tubs are a much more lightweight design meaning they are much easier to manoeuvre into position.
Heat up times from tap water temperature are from around 1.5 hours.
Electrical Hot Tubs also require complex chemicals due to the filter systems.

Do the tubs require an electricity supply?

Yes and no!
With the heating element coming from the fire and not from electricity, an electric supply is only required if you wish to power the LED lights & bubble systems.
Some customers opt to power the electrical elements using leisure batteries, solar power or generators - allowing for a completely 'off-grid' setting!

We advise 'Active Silver Oxygen' from Clarion Spa. This is a much milder & environmentally friendly alternative to the harsher Chlorine type chemicals.
Active Silver Oxygen treated water is also much kinder to sensitive skin, easier to dose & allows the water to be repurposed on plants around the garden!
For our Hydro bubble system, water treatment is highly recommended.
All of our tubs are designed to be both Chlorine & Bromine resistant.
We do recommend the use of water treatment to help maintain the general health of the Koto Hot Tub.

This requires a very short learning curve but will be very simple to those who have experience with a household wood burner.
Leaving the vents on the boiler door open will keep the fire roaring & increase the temperature of the water.
Once the desired temperature (usually around 40 degrees for most bathers!) is reached, sliding the vents closed will restrict the oxygen supply to the fire and so reduce the burn - allowing you to maintain the temperature.

For commercial settings, we recommend full water changes between customers.
For personal use, it will vary on a number of factors including:
Children – getting in and out with muddy feet!
Creams – sun cream, fake tan etc.
Food or debris
Quality of the water
Whether water treatment is used eg. Chlorine, Bromine or Active Silver Oxygen.
We’d expect that the average user would get several uses over several days with their tub and will very quickly find a routine that suits them.

In general, 1.5 hours is around the lead time to expect.
We use a unique double-induction boiler providing us with some of the market-leading heat up times.
This really is variable depending on quality of wood being burned, atmospheric temperature and whether the Insulated Cover has been placed on the tub.
With the Insulated Cover in place the heating time will be significantly reduced than if there is no lid in situ.
Other tips for heat up is to turn the bubble system on for a few seconds every now-and-then to help circulate the warm water.
Heat up can take anything from 30 minutes (the day after use where the lid has been replaced) and 3 hours in the depths of winter.

Kiln dried wood is what we always recommend.
It is essential that the wood has low moisture content (sub 20%).
Kiln dried wood will allow a high burning temperature - resulting in minimal smoke on heat up & optimum heat up times.
Coal is not to be used with the tubs.

The tubs can be placed on any surface providing it is level & structurally capable of supporting the weight of a filled tub.
If you are planning to place your tub on decking, we recommend utilising the hoselock adapter included with your tub and emptying the water via a hosepipe.
Allowing the water to free-drain on wooden decking runs the risk of damaging the decking over time.
We'd also recommend the use of a hearth (some slate, marble etc.) underneath the door to the boiler in case of any spiting from the fire.
Consideration should also be given to how/where you plan to empty the water.

To get the Koto Tub to 40 degrees, it will take approximately 10x quarter split 8 - 12 inch logs & a good handful of kindling.
This will vary depending on atmospheric temperature, the starting temperature of the water, whether the Insulated Cover is in use and the quality of the logs.

Cleaning - Firstly, Empty the water. We then recommend using a mop (ensure it is plastic – metal or wooden edges could scratch the fibreglass interiors) and some diluted household cleaner, such as disinfectant. Once you have given the tub a thorough clean, ensure that it is thoroughly rinsed with clean water using your hosepipe. The tub is now ready to refill.
Maintenance - the wood has been treated to weather over several years. You may find that in harsher environments that the finish can become dull. If this occurs, treat your tub with Danish Oil.