Using Chlorine in a Hot Tub

Chlorine is the traditional pool and spa sanitiser, but unfortunately it is also the nastiest and one of the the hardest sanitisers to use correctly.  Chlorine is very sensitive to pH fluctuations and doesn't work effectively if the pH is outside of the optimum range. In addition, chlorine is toxic, it is smelly and it can cause skin and eye irritation. In order to use chlorine to sanitise your hot tub you'll need to perform the following steps: At Each 3 Monthly Water Change Clean the Plumbing: Add a spa flush or plumbing cleaner to your existing tub water and turn on all jets and pumps for at least 30 minutes. Remove the filter(s) during this process if you are able to run your pumps without the filters in place. It’s preferable to leave the plumbing cleaner to work overnight if possible. Drain the Tub: Use a non-scouring pad to wipe away any deposits left on the shell as the water drains. For significantly dirty spas use a specialist spa surface cleaner. DO NOT use any household cleaners. Clean the Filter(s): Rinse any debris from between the pleats under a running tap, or use a specialist filter cleaning tool on your garden hose. Sprinkle a powedered filter cleaner all over the surface of the filter(s) and place them on the bottom shelf of your (clean) dishwasher. Run the dishwasher on a normal 50ºC wash cycle. If your filter(s) won’t fit in the dishwasher then soak them overnight in a suitable container using a powdered filter cleaner, then rinse thoroughly. Allow your filter(s) to dry naturally before replacing them in the tub. This is important because the filter material will last much longer if it is allowed to thoroughly dry between uses. Filters can take a very long time to dry so it’s a good idea to keep a spare set and to rotate them each time you clean them. Refill the tub with clean water. Do not use softened water. Balance the Water: Test the water using chlorine test strips and adjust the Total Alkalinity and pH , using the directions on the water balance product containers: the Total Alkalinity should be within the range: 80 - 120 ppm the pH should be within the range: 7.2 – 7.8 the Total Hardness should be in the range: 250 - 500 ppm You should first adjust the Total Alkalinity, then when that is in the correct range adjust the pH and finally the Total Hardness. You must persevere until you get the correct balance because the chlorine won't work effectively if the balance is outside the required range. Add the Chlorine: You will need to use chlorine granules to give an initial shock does of chlorine to a freshly filled spa. Pre-dissolve the weight of granules recommended on the product container in water in a clean plastic bucket, stirring well to make sure that the granules are completely dissolved. Apply the solution to the spa whilst the pumps are turned on to aid distribution. You should aim to maintain a chlorine level of 50ppm for 1 hour or 20ppm for 2 hours, you may need to add additional chlorine to maintain this level. After the initial shock, allow the chlorine level to reduce to 3-5ppm. Test the water after 30 minutes and at intervals, if necessary, and do not get into the water until the level has reduced to less than 5ppm. Regular Maintenance Daily: Check the water balance using chlorine test strips and adjust as necessary to maintain the range specified above. Apply a maintenance dose of chlorine by pre-dissolving granules in a clean plastic container and applying to the spa with the pumps running to maintain a reading of 3-5ppm. As an alternative to applying chlorine granules daily you could use 20g Chlorine tablets either in your spa's in-built chemical dispenser or in a floating dispenser. Chlorine tablets dissolve slowly and evenly to give consistent and long lasting chlorination, avoiding the need for daily dosing, but some tablets have a very low pH and so they can consequently reduce the pH of your spa water leading to the potential for equipment damage and skin and eye irritation. Do not place chlorine tablets directly into a skimmer basket or elsewhere in your tub. NB. If you use chlorine tablets you will still need to check and, if necessary, adjust the water balance daily because chlorine is very sensitive to pH fluctuations. Weekly: Use a chlorine-based shock treatment to remove non-filterable organic contaminates. You should shock your tub weekly as a matter of course. It is also a good idea to shock after any period of very heavy use or if children have been in the tub (let’s be honest, it’s not a very attractive proposition to get out of that lovely hot water to find the loo!). NB. Don’t check the chlorine level for at least 12 hours after you have applied the shock because you will get an incorrect reading. Clean your filters weekly as described above. 3-Monthly: Clean the plumbing and change the water as described above. Chlorine Facts Here are some things that you should know if you decide...

Chlorine is the cheapest form of santiser for your hot tub water but did you know that it is probably the worst choice you can make? It's the most difficult and time-consuming sanitiser to use and it is not well suited to the hot water in hot tubs. Just take a look at some of the reasons why you should look for an alternative to Chlorine... 1. It's complicated and time consuming! Adding Chlorine to hot tub water is not straightforward. You need to get the Total Alkalinity, pH and Calcium Hardness levels in your water just right (this is otherwise known as 'balancing') and you must always do this before you add any Chlorine product, otherwise the chlorine becomes ineffective and won't sanitise! Just the process of adding Chlorine granules or tablets to the water has a tendency to alter the pH value, which will also change with temperature, sunlight and numerous other factors; so you need to constantly keep testing and adjusting the water's balance to ensure that the chlorine remains effective. It can be a never ending loop! Chlorine added to 'unbalanced' water will create Chloramines that do nothing to clean your hot tub's water and will just leave a 'bleach' like smell above the water's surface.   2. It's not good for your body! Exposure to chlorine compounds and their by-products often result in allergic reactions and skin irritation. When chlorine combines with organic matter like urine, sweat, etc. it leads to the development of dichloramines, monochloramines, and trichloramine, which are all strong irritants. Some of the symptoms that can be caused by Chlorine exposure include: dry and itchy skin. The resultant case of chlorine rash may elicit peeling of the skin. coughing and sneezing. nausea, vomiting and pain in the abdomen. short term problems in breathing and pain in the chest. 3. It can ruin your bathing costumes! Bathing costumes used in hot tub water at its normal operating temperature, combined with a Chlorine sanitizer will suffer from high levels of colour fade as well as losing their elasticity. Chlorinated water produces hydrochloric and hypochlorous acids. The latter is a component found in household bleach which, if spilt on your clothes will cause permanent damage. 4. It's not good for your eyes! In a hot tub, the pH value of the water is the major factor in eye irritation. A well maintained tub will keep the pH balance as close to 7.4 - 7.6 as it can ie as close to matching your body's natural pH balance as possible. The addition of Chlorine will lower the pH of the water and and cause it to irritate your eyes. In any hot tub, the chlorine does not always oxidize the organic matter in the water completely. This residue consists of a whole range of organic compounds, including Ammonia, which can cause further eye and skin irritation. 5. It will ruin your hot tub cover, headrests and plastic fittings! The insulating foam inside you hot tub cover is wrapped in plastic to keep the moisture out of it.  Chlorine vapour will very soon attack this plastic wrapping causing the plastic to get brittle and crack.  As soon as this happens the foam will start to absorb water vapour, it will become very heavy and it will stop insulating properly.   Just one accidental 'over-dose' of chlorine in your hot tub can start the cover degredation process which will very soon result in a damaged cover which will cost you a lot of money to replace.  

There is a wealth of evidence that chlorine is harmful to health. For example, the United States Agency for Toxic Substances & Disease Registry (ATSDR) has published data that shows that the following effects have been observed in humans briefly exposed to chlorine (Nov 2010 Cas#:7782-5-5) : - mild nose irritation at 1-3ppm - eye irritation at 5ppm - throat irritation at 5-15ppm - immediate chest pain, vomiting, changes in breathing rate and cough at 30ppm - lung injury (toxic pneumonitis) and pulmonary oedema (fluid in the lungs) at 40-60ppm - death after 30 minute exposure at 430ppm - death after a few minutes exposure to 1,000ppm The concentrations listed above are approximate. In general, people who suffer from respiratory conditions, such as allergies or hay fever, or who are heavy smokers tend to experience more severe chlorine exposure effects than healthy people or non-smokers. Manufacturers of hot tub chlorine recommend a dosage of 5ppm of chlorine in your hot tub during daily use and significantly higher levels for regular shocking. There is overwhelming evidence that these levels of chlorine exposure are harmful to your body.