Best Red Algae Control??

[mechano]

Agreed. Canister filters are a problem waiting to happen, and tend to become nitrate traps(if filtration is used)
In the the time in this hobby I have never ever ever ever found a good 100% solution to hair algae-red or green when it comes to fish or inverts.

I think the only way to truly fix the problem is:
1/Water changes
2/clean rock or and hope stuff doesnt grow back
3/lower nutrient import into tank
4/ And if none above works, take out the bad piece of liverock and boil it because there is probably something in the rock like a dead crab or worm that has sparked the algae bloom on that rock and allowed the algae to gain a foot hold. IMO of course.

good luck

[George]

Test kits may or may not give you readings because cyno (actually a bacteria instead of an algae so most fish don't touch it) can take up the nutrients as soon as they get released.
What is your water source? What is your substrate if any?