Nobody can answer that question until you "test" your water. To determine the solution, or the outcome, you must understand what you are fixing, test the water. If everything is normal and OK on the test strip, and your water is foul and ugly, it takes far greater effort to bring it back from the dead than to dump it and start fresh. You have recently done this and I don't see the need to do it again, other than understanding what caused your water to be as it is.
I have had customers using ozone with great success, but you still must monitor pH and Alkalinity. One customer was upset when we had to change pump 2 out and had to drain the spa. The water was 7 years old, and had not been changed since we delivered the spa. So let me ask, do you need to drain the water, only if it is necessary. Chemicals have inert ingredients that accumulate in water and require frequent changes. Ozone is a gaseous form of sanitizer that constantly is working without you and kills more efficiently and effectively than chemicals and leaves no residual behind, other than dead matter to be filtered clean.
As for the 7 year old water, it was sparkling clean, and it was crystal clear. We took water samples and bacteria samples and the water tested perfectly good. I commonly find "aged water" in perfectly good condition, using Ozone.
Do you have Ozone on your spa.
What does your test strip reveal for pH and Alkalinity?
