I have an Hawaiian Ti plant that has grown nicely since I bought it as a log in 1971. It has flourished no matter where I had it. It now resides in the largest plastic pot I have been able to find (approximately 2 feet in diameter) and was re-potted in Nov 2013. It gets sufficient water, fertilizer and light but recently the leaves are turning brown. This has happened in the past but not to the extent that is happening now. A couple years ago we put in a water softening system that uses potassium chloride pellets. This water is what I use on the plant. Is it possible that this plant is getting too much potassium through the water softening process? Could that be a cause of this problem?
Brown leaves on a Ti Plant are a generic symptom with several possible causes, so I cannot say for certain that the water softener is the sole cause. However, the mineral salts added to water softeners are definitely not good for any potted plants. Cordylines (Ti) and Dracaenas are particularly susceptible to excess mineral salts. Over time, these mineral salts build up in the soil and become concentrated enough to burn the roots and cause leaf discoloration.
I suggest you take plain water that is not hard or softened and pour it through the soil several times to flush out the excess soil salts. Use filtered, distilled or rain water. The leaf browning should gradually subside, although already discolored leaves will not recover.
With very large pots, inadvertent over watering is a very common problem because the excess soil retains moisture around the roots for a very long time. Be sure that the soil dries out sufficiently between waterings.