Pool Tip of the Day – Salt System? What is your TDS?

Published April 16th, 2019 by Advantage Pool Services, Inc.

Today I’d like to talk about Salt Pools, Salinity levels, and the Pros and Cons. Join the conversation! Tell me about your experiences! I love reading comments about your pools and answering questions! To begin, a Salt Pool is another system to introduce disinfectants into your pool water. It uses a process known as “electrolysis” to convert Salt into Free Chlorine. The process is fascinating and yet very basic in terms of chemistry principles. Electrolysis is a method of separating bonded elements and compounds by passing an electric current through them. The chemical makeup of salt is Sodium Chloride (NaCl). Your “salt cell” is made up of thin metal plates that are close together but not touching. An electrical current is connected to the plates. When the salt water passes through the cell, the electrical current flows through the salt water and “breaks” the salt water into Hypochlorous Acid (HCIO) and Sodium Hypochlorite (NaCIO). Sodium Hypochlorite is the same exact chlorine we all use in swimming pools as a disinfectant. So, a saltwater pool is not actually a non-chlorine pool; it simply utilizes added salt and a chlorine generator (salt cell) instead of direct addition of chlorine. Like traditionally chlorinated pools, saltwater pools must be monitored in order to maintain proper water chemistry. Low chlorine levels can be caused by insufficient salt, an incorrect (low) chlorine-generation setting on the SWG unit, higher-than-normal chlorine demand, low stabilizer, sun exposure, or mechanical issues with the chlorine generator. Salt count can be lowered due to splash-out, backwashing, and dilution via rainwater. **Note – Many times during the summer, your salt cell may have a hard time keeping up with the necessary chlorine generation for the same reasons listed in the previous paragraph. It is a good idea to keep liquid chlorine and some Trichlor tablets on-hand to assist the generator in maintaining a sufficient chlorine level. In order for your Salt pool to run efficiently and produce Free Chlorine, you must first keep the salt level between 2,500 ppm and 3,000 ppm. Check your manufacturer’s recommendations to be exact. The salt levels can be measured with a TDS (total dissolved solids) meter. If the TDS is too low, add more salt. If your TDS is too high, remove water and replace it with fresh water. **Note – Your pool pump must be running for your salt system to produce chlorine. When your pool pump is not running, you will not be producing chlorine! The Benefits: Salt systems in pools are convenient and provide a constant delivery of pure chlorine-based sanitizer when the pool pump is running. There is a perceived reduction of irritating chloramines versus traditional chlorinating methods. The “softening” effect of electrolysis reducing dissolved alkali minerals in the water are also perceived as benefits. For some people that have sensitivities to chlorine, these systems may be less offensive. Salt water pools are cheaper to maintain throughout the year, since salt is significantly cheaper than the commercial chlorines. $10 can buy about 40 lbs. of salt versus only 5 gallons of liquid chlorine.

The Disadvantages: The initial cost of the salt system, maintenance costs, and the cost of replacement cells is a disadvantage to consider. Salt is corrosive and will damage some metals and some improperly-sealed stone. However, as the ideal saline concentration of a salt-chlorinated pool is very low, less than 3,500 ppm, damage usually occurs due to improperly-maintained pool chemistry or improper maintenance of the electrolytic cell. Pool equipment manufacturers will not honor warranties on stainless steel products damaged by saline pools. Have a question or concern?

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