It's not the shock — it's your filter or your pH

Probably.

Shock kills stuff — algae, bacteria, organics. But it doesn’t remove the dead stuff. That’s where your filter comes in. If the water stays cloudy after shocking, either the filter isn’t running long enough or your water chemistry is off.

Check pH first. If it’s above 7.8, your shock won’t work properly and particles won’t clump together for the filter to catch. Also check calcium hardness and cyanuric acid. High stabilizer (CYA) can lock up your chlorine so it never actually oxidizes anything. And if you used non-chlorine shock, it doesn’t kill algae — just oxidizes. So if you have algae, that’s not the right tool.

Run the pump 24 hours after shocking. Clean or backwash the filter. If it’s still cloudy after two days, test for phosphates or bring a sample to the pool store.

Fix the chemistry, then let the filter run for a day or two.