Pump questions

So we bought a house with a pool....I replaced my sand filter last summer, and I had a beautiful pool all year. recently we have had some algae issues. yesterday I tried to vacuum the pool and had little suction. I cleaned the basket inside the pump and then could not get a strong prime back. The water is flowing but does not fill the tank to the top of the see through top, there is 0 pressure reading on my filter but the jets are moving and the skimmer is moving also....what do I do now?

Hi Nikki and welcome to PoolForum!

Can you tell us some more about your pool and filter?
How big a pool is it, and what type?
What brand and model of sand filter and of the pump as well?
How many returns do you have?

And then we can try to figure out what's going on. At the moment a wild guess would be air bleeding into the system.

Carl