Help with sizing new filter

[jtran69]

Hi Carl,
Let me know if I should post this on new thread.
After 2 weeks out of town, pool is now slightly green from the vinyl everywhere due to pump working very poorly. I added a gallon of chlorox bleach and 4 cups of kemtek dichloro last night. Before adding, I've tried to vac the green algaes but pump kept beeping with low flow and self shut offed shortly. I have noticed that the pump had been losing the flow rate after the second season and now it's completely useless.

My current Intek has pump with SWG built in. Is it possible to buy just the pump connect it in series before the Intel so the SWG would still work. .

The intek worked OK when new but still very weak when adding 25 feet vac hose - it would beep for low flo and shutdown shortly. Vac hose attaching to intek skimmer is likely 1 inch....

I'd like a 2 speed pump and use hi speed for vac.

Please advise on my disaster situation?