You know, I've been trying Aiptasia-X. It does work on some, but in the past month, I've used it on HUGE aiptasia or Majano (how can you tell the difference?) and they just "come back" after a day or two.
I was going to try Joes Juice, but my two bottles are just calcium encrusted empties. So I took some pickling lime/kalk and mixed it into a paste just liquid enough to squeeze though a syringe, then I added some salt to it (I had read Joes Juice was just kalk + salt + water). I put some on the aiptaisa/majano and ... Holy Crap! It worked!
It's been two weeks now and the mega-aipt/majs are gone! Sure, I've got lots of other ones, but I was really impressed that this stuff worked.
Maybe it's best to do a rotation of killer methods. Kalk-paste/Joes/Aipt-X/whatever.
I've also read that sodium hydroxide (ie Rooto drain opener) works as well, but the instructions I've found on it's use are terrifying.
Wow, if you have kalk/pickling lime, give the paste + salty water (tank?) a try before buying any other specialty products which are, in all likelyhood, variations of kalk-paste.
I'm not sure about now, but Walmart this year carried a lot of pickling lime, it might be out of season now though. I bought a bunch of it for < $3/pound.