The ecoone® ONEshock™ product is nothing more than 0.25 ounces of Dichlor in a pre-measured self dissolving packet. So what you are buying is the convenience of these pre-measured packets. They recommend one packet per 250 gallons and they say to wait 5 minutes and test the chlorine level which should measure 2-3 ppm, and that one should maintain 2-3 ppm FC in the spa by adding more packets as needed in between soaks. Note that one packet would roughly handle approximately 25 minutes of soaking for one person so for a typical 20-30 minute soak using one packet per person should work about right. Note that you need to add more packets (chlorine) in between soaks to maintain a residual. I'm assuming the 0.25 ounces is for the Dichlor contents; if it's the weight of the packet, then there is less chlorine in each packet than I described.
So this really isn't any different than using Dichlor-only except for the convenience of the packets. One will still get a buildup of CYA in the water though their monthly "SPA monthly" product is a clarifier that will reduce the inevitable cloudiness that would result from the CYA buildup causing chlorine to not oxidize bather waste quickly enough in more heavily used spas.
The Dichlor-then-bleach method is much less expensive and the water lasts a lot longer between water changes, but it's obviously not as convenient since it doesn't have pre-measured packets.
The full instructions for the ONEshock product are as follows:
DIRECTIONS FOR USE
1. Chlorinate: With jets running, add .25 oz. (one, ONEshock� dissolving packet) of this product per 250 gallons of water. Wait 5 minutes, then check chlorine residual. Residual chlorine must read between 2 to 3 ppm.
2. Maintain: This product should be added daily or as necessary to maintain 2 to 3 ppm residual chlorine. Frequent checks should be made of residual chlorine using a reliable test kit. Allow at least 5 minutes mix time before sampling. Note: Heavy bather usage or the use of oils or lotion may increase the chlorine demand of the spa or hot tub resulting in the need for more frequent checks of chlorine residual.
3. Check pH: pH should be monitored with a reliable test kit and maintained at 7.2 to 7.8 range for clean, sparkling water. pH can be decreased by adding a suitable agent such as sodium bisulphate or increased by adding a suitable agent such as sodium bicarbonate.
4. SUPER-CHLORINATION: It is good practice to super-chlorinate each 2 to 4 weeks. To super-chlorinate, add 1/2 oz. (two, ONEshock� dissolving packets) of ONEshock� for each 250 gallons of water. Thoroughly clean spa, vacuum and cycle through filter. Resume program when chlorine residual reads 2 to 3 ppm.
