Kinda blurry, but they look like aptasia. I've not used aptasia x- I have aptasia control by blue life. Works well for me. Make sure and shut down pumps and water flow so you dont accidently get it on the wrong thing. For the ones that were to deep for me to reach or in impossible spots... I bought some of the aptasia eating nudibranches....they work great. I havnt had to use the aptasia control stuff since I added them to my tank. They seem kida pricey for suck a tiny thing (i pd $20 ea) but over time paid for itself since i wasnt having to continue buying the poison. Maybe someone local has some you can borrow (or they've multiplied & need new home). They only eat aptasia. I didnt notice a big change right away... It took a couple weeks until I noticed a couple of pests i usually glared at was gone....then really looked hard and couldnt find any. I know mine are still alive because I spot them every once in awhile...so I take that to mean that they still pop up because the nudi is alive and grown alot. They just dont have a chance to grow big enough that I see them.
Good luck!