algaefix will temporarily provide a fix, not a permament solution to the problem.
for HA to grow, it needs nutrients and light..
soooo, here come the questions
:
when is the last time you changed your lights?
what is the nitrate, nitrite, ammonia, phosphate and Mg levels?
what is the pH level.
do you use sand, if so, what kind and how many inches thick is it.
do you use a RO/DI unit?
what type of filtration do you use?
how much "gunk" is being pulled out of your skimmer a week...
depending on the severity of HA on the rock, you might have to manually pull it off, otherwise, it will take forever to go away on its on.
bottom line, there is not a panacea to your problem and this will take alot of time to solve..first, need to identify the problem, then you can start to fix the problem..
I've been battling HA and bryopsis for almost a year, and had to call in some professional help..several problems were identified, and fixes are now in place..it has been 3 weeks and no more HA on the sides of my tank, unfortunately is still on live rock and I might be pulling out all LR and buying new cured LR.