Test the pool water to determine the current chemical levels. The recommended pH levels are 7.5-7.8, total alkalinity 70-90 ppm (parts per million) and cyanuric acid 30-50 ppm. Bring the chemical levels into balance before starting the conversion to make the process easier.
Stop adding Baquacil to the pool. Continue testing the water until the Baquacil is at zero. This process may take several weeks depending on the size of the pool and how much Baquacil is in the water. Since Baquacil differs from chlorine and is not affected by sunlight, temperature or pH fluctuations, it may take some time for the Baquacil to dissipate.
Clean the filter medium. For a diatomaceous earth (DE) filter, backwash it to flush the Baquacil and other dirt out of it and then clean with a cleaning product designed for use with that filter. Baquacil leaves behind a chemical residue that must be eradicated prior to adding chlorine or Nature2 to the pool. For sand, replace the sand and for cartridge filters, either replace the filter or thoroughly clean it with the manufacturer's recommended cleaning product.
Shock the water using non-chlorine shock. Keep the pump running 24 hours a day during this step. Use eight pounds per 10,000 gallons of water, dissolve half the shock in water, add it to the pool, wait 24 hours, and then add the remaining shock. Re-check the chemicals, and if the Baquacil level is at zero, balance the water. If not, keep the pump running and add more shock until the reading is at zero. The shock helps to keep the algae in check while the conversion is in process.
Install a Nature2 sanitizer unit to existing pool plumbing. Several different types of units are available from the Nature2 website for use with inground and above-ground pools of varying size. Choose the unit that fits your current swimming pool, add the mineral cartridge and active it by running the pump and water through the new system.
Recheck water balance and add correct chemicals to bring water to recommended levels. Begin adding chlorine slowly until the levels reach 0.5 ppm, lower than the recommended levels of 2.0 to 3.0 ppm for systems that don't use Nature2. Change the cartridge every six months or at the beginning of each season.