Aptasia will never go away without braking your tank down.
Aptasia will live in your hoses, sump, overflows, just about anywhere. They will always exist in your tank but u can eliminate them from the display tank.
You can control it in several ways, the fastest and nicest way is by getting a copperband butterfly or a matted filefish.
Since u hardly have corals I would go with either fish, if u plan to add corals go with the butterfly.
U can try alternative ways but u will waste your money and time. U can try juices, paste, zapping, trust me, they will win and u will lose.
Add a natural predator fish and in a month they will be gone.
The peppermind shrimp work but shrimp don't eat the adult aptasia and shrimp prefer waiting for u to feed the tank rather than eating nasty anemones. Shrimp "disappear" as well, u could end up spending more on shrimp then on copperband fish.
Chose your weapon and good luck