The number one reason you should avoid salt systems for your fiberglass pool is corrosion.
Any pool equipment that is metal will become corroded due to salt systems. This is 100% inevitable and there is nothing that cn be done to stop it.
The worst part is many manufacturers state that their products are salt friendly and salt safe, but in reality and metal component connected to your pool is at risk.
Not only do salt systems cost more to own and operate versus a tridational chlorine pool, but the repairs to your pool equipment are what will cost you thousands. The photos below shows the true cost of salt pool ownership.
The use of bonding and sacrificail anodes are 2 steps to help reduce the likelihood that this will happen but there is no way to stop it altogether other than never use a salt system which is what I recomend.
SO WHAT IS GALVANIC CORROSION
The final factor to consider when thinking about converting to salt water is something called galvanic corrosion. This is the process where dissimilar metals are submerged in an electrolyte solution developing a current that travels in between metal components in the water. When submerged, these differing metals will develop a tiny potential electrical difference between them which is called "voltage". Submerging dissimilar metals in salt water is how you make a battery, and if action is not taken to prevent this from happening with your pool, then you will have a 25,000 gallon battery that operates 24/7 in your backyard - slowly eating away at your pool. Inside the pool and part of the pool equipment are all sorts of metals such as nickel, galvanized steel, copper and titanium. Since all of these metals are located in the salt water, it is possible to develop a small electric charge across these different metals. Over time this very small voltage would cause severe corrosion of whichever metal is the weaker (less noble) of the two. Titanium and stainless steel are more resistant where copper, galvanized steel and zinc are much more inclined to corrode during this process. What this boils down to in your pool is rotted wall panels on vinyl pools, stainless railing and light niche oxidizing and premature failure of heater internals, to name a few. The good news is that there is a system to slow this process. The bad news is that very few salt water pool owners know about it or have one installed.
A sacrificial zinc anode or series of zinc plates are added to the system so that they become the weak link (least noble) metal in contact with the pool water, and this will help to protect the integral pool components against galvanic corrosion. Zinc will corrode faster and more readily than any other metals. So as long as you keep the pool in fresh supply of zinc plates to corrode, then all the other metal components will recvieve less of the damage. Be sure to understand the process of galvanic corrosion before you install a saltwater system to prevent damage to your backyard investment.
Other Disadvantages to Salt Water Pools
1: Damage to pool decking. Certain concrete finishes can be deteriorated by salt water. Expensive stone copings like bluestone will deteriorate rapidly when introduced to salt water. We all know bluestone is not cheap either.
2: Salt water kills plants and grass as well.
3: If used on an in ground vinyl pool with steel walls or and above ground pool with steel components it can and will deteroriate the pool. Most manufacturers of these types of pools offer no warranty if a salt system is used.
At Pool Pros we recomend staying away from Salt Water Pool Systems. It will cost you more money to operate and more money to repair your pool than any other type of sanitizing system available. Salt Systems are good for one thing, return business to repair your pool. Pool Pros does not want that type of business though. We want all of our pool owners to be fully aware of all the risks associated with owning a salt water pool up front. Our goal is to build you the best pool with the lowest long term cost of ownership and hassle free use.
For the best water quality, lowest cost of ownership, reduced chemical usage and trouble free use take a look at our Delta UV system. It is an alternate sanitizer that does not add any chemicals to the water and does not affect water chemistry. It simply increase the efficiency of standard chlorine in turn reduces the amount of chlorine needed to keep your pool clean. Take a look for yourself (link to Delta UV Blog)