Never add cycling bac to a cycled tank, because it doesn't do anything. It prevents taking helpful action and the bacteria compete for oxygen and increase suspended bioloading which is opposite of what the reef needs.
If you are reading this thread to cure a tank invasion from a link I sent you, we do not need to identify your type of invasion here we do not need you to test anything at anytime regarding nitrate, phosphate etc Above all, we do not need to see a microscope slide picture of your invasion at...
www.reef2reef.com
This above will fix your tank, it's fifty pages of fix. Study it for two hours, then run it. Once you are familiar with rip cleaning, do this below to fix aiptasia.
https://www.reef2reef.com/threads/first-aiptasia-sighting-what-would-you-do.808233/page-2#post-8647852 notice in the thread the surface with aiptasia was removed from the reef, and what was beside the aiptasia frag was taken off and moved back onto the reef allowing the aiptasia + the surface...
www.reef2reef.com
You could buy a simple uv sterilizer and it may work, but we didn't do that for fifty pages because dead bacteria will be sinked into a system already loaded up, notice how there's only perfectly clean tanks in the after pics? That's the benefit of the rip clean.
Your sandbed is full of waste, time to fix that and the reef will mature nicely. Don't take reef surgery lightly, study the examples well then execute the move without hesitation rinsed exactly as everyone did there successfully.
Example from page one, Shadow_k had one similar to your challenge:
A few hours later after rip clean
One month later
Look at how clean his sandbed cross section is now
There is no doser, parameter adjustment or set of animals that can do this shocking turnaround. Reef tank surgery did it for years all in one thread. If you follow the rules exactly, your tank will follow suit
A simple uv sterilizer is 98% likely to clear up the water but it doesn't do anything for the loaded sandbed. That's a green hair algae pump and cyano pump later on, if left unaddressed. The sandbed waste is kicked back up in the tank during water changes but when clean will not.
