Sarge

My AquaPure 1400 4 years old. Two months ago the sensor went bad and was replaced. I went got what looks like a generic one from discountpoolmart.com(?) for around $150 before shipping & handling. A few days ago, the cell went bad - an electrode was corroded and fell off. Service codes 125 & 194. I tried to repair it - and it worked for 2 days. Then I got the low voltage service code of 120. The next day displayed 125 and 194 again. Question: PoolSupplyWorld.com has the entire system for $849.95 and a replacement upgrade kit for under $600. Which one do you folks recommend me getting? Thanks.