Best Shock for Algae

[Anonymous [GDPR] European in the UK]

Thanks! I guess I need to educate myself a bit more on chemicals. I assumed "shock" purchased from the pool store had something else in it!

Now you mention it, yes it has. Usually more cyanuric acid stabiliser, A lot of pools get into trouble through being over stabilised so adding bleach removes that issue.
Very powerful shock (HTH brand etc are calcium hypochlorite) this doesn't contain stabiliser but is usually more expensive than bleach and can add even more calcium hardness.
That means bleach is the way to go!