Djames; get a proper test kit. TF-100, read and learn the Trouble Free Method and how to interpret the results. ...get out of the Pool Store, they are like a crack dealer...and with your newfound knowledge reject the Junk they want to sell you.
Please post your pool stats so we can see them. Equipment and water measurements. The TF 100 will test pH, Free Chlorine, Combined Chlorine, Stabilizer Level, Calcium, and Total Alkalinity. Post the numbers. Since you have a Salt Water CL Generator, get the SALT water test kit option too...important.
Sounds to me as if your CYA levels are too high...what has your primary source of CL been for the last few years....let me guess, the Pool Store has been feeding you a steady diet of Stabilized CL tabs for three years. I see this all the time when people are loading the pool with liquid or powder shock CL because they have algae... only to see the next day yellow or green again. This is a highly probable sign of too much CYA accumulated slowly over time using the Stabilized CL Tabs......and the algecide is wasted $$$. Actually, the ONLY time to use an Algecide is when closing a pool after SLAM (and only use polyquat). Too low CYA and the free chlorine evaporates in the sun, too high (your case as I expect) renders the free chlorine useless. How do I know this: It happened to me before I got on the TFP bandwagon.
Once you get on the TFP method, you'll be proud of the freedom and knowledge you have gained. And happy to say "Sianara" to the Pool Store folks.
