I've never really had an aptasia outbreak,but have had some come in on Rock that was bought here locally. I can't remember the dosage but as I work industrial and we have sodium hydroxide about,I brought some home and mixed it up and nailed those little bastrds with a needle. IME it killed them stone cold dead and they didn't come back! I have used it on rock inside and outside of the tank. No ill effects were seen in the tank as well. Although I did it before I did my WC.

If you "mixed it up" what was the concentration? Even if it works I couldn't reach 1/2 of the critters and that is of the ones I can actually see.

As I stated above I can't remember off hand what the ratio of water to Hydroxide to use.
I'm sure I have it one of my binders in storage...I'll have to look for it. So you couldn't reach yours.....so how does that translate into "even if it works". Is what your saying it doesn't work?

The recipe I use with lots of success is:

1 tsp Calcium Hydroxide
2 tbls water
Boil for 40 sec in microwave.
That's it!

I think I may have used this one you posted myself. I know there was another one that called for a spice jar and 1 or 2 tablespoons and there was no need to heat,the Hydroxide would heat it up itself. Thanks for posting that recipe!!

I don't know if the heat is required but I do it anyway just before I squirt the little buggers. I think maybe that because the liquid is boiling hot that it helps kill the aiptasia as well?

i had a HUGE outbreak, all my rocks were covered with those darn pests, i think it was at least thousands of them, my rocks seems like they were growing hairs,, i use 5 peppermint shrimps (the ones i got from kevin red coral) and i got one copperband, it rid of all my aiptasia from all rocks in 2 weeks