I have been using a chlorine generator for the past few years, and now I have to replace the top rail of my pool due to corrosion caused by the salt, so I am going to go back to an in-line chlorinator. I have been trying to find out how much water I should drain from my pool to get the salt level down to a non-corrosive level, but I can’t find anything on it. My local pool store says it is the process of breaking down the salt that caused the corrosion, and I can leave the salt in the pool without any problems, but I’m not sure if I believe that. Can you offer any insight? Thanks, in advance, for you assistance.
Hi Doctor,
The only reason you would need to drain the pool is if you need to lower your CYA. Typically on a salt pool you maintain a higher CYA in the range of 70-80 and for a non salt chlorinated pool you will maintain a CYA of 40. If you are using chlorine tablets then this is stabilized chlorine which will drive your CYA up. So the first thing you will want to do is measure your CYA and post your results here. Once we see those results we will know how much if any water will need to be drained from the pool.
Thank You
Patrick
So the amount of salt left in the pool will not be an issue? I don’t want to have to replace my top rail a second time.
Hi Doctor,
It is the electrolysis created by the salt system that causes the corrosion and not the salt iself, so if you are no longer using the salt system then you will be fine with the salt staying in the pool. Here is a Video we put togeter on Electolysis & Rust in an Aboveground Pool that will explain this in further detail.
Thank You
Patrick
Thank you Patrick!
I must admit to being a little confused, however. I have always heard that salt is corrosive, so why isn’t is corrosive in my pool? Or is it just that the concentrations in the pool are so much lower than seawater?
TheDoctor - You are correct about the pool salt level being much lower than seawater. The salt level in a pool (3,000 ppm) is less than 1/10 the salinity of sea water (35,000 ppm). The water in a salt pool is not anywhere close to being as corrosive as seawater.
Another question. If using a sacrifical zinc anode, I could continue to use my chlorine generator, correct? Do I need all those different units, or do I just need one somewhere in the water? Thank you for your time, I really appreciate it.
Yes you can continue to use the chlorine generator with the zinc anode. You will just need one Zinc Anode in the water.
I have an ingound Gunite pool and it is salt water. I have a steel spiral staircase and other metal items that corrode. I was thinking about converting to chlorine also but not sure. I had an ingound chlorine pool before and no issues. I also have a little black mold spots coming up and I have to brush them away. I had a pool supply run analasys and I had to treat with a bunch of chemicals. All that left was like a lime rim on my tiles that hardly will scrape off. So I am reluctant to go back.
We have also recently come out with this Article on Converting Pool Back to Chlorine from Salt which you may find helpful