just chiming in bored day
to beat the hair algae you have to deal with nitrate and phosphates first, lighting adjustment won't be the prime mode for reasons you mentioned. Yes some pH support suffers with reduced lighting, because intense lighting>photosynthesis sequesters carbon dioxide from the water (removing/binding carbonic acid) and drives up the pH. Good ion supported water may not suffer with reduced lighting, but it's been shown that actual physical removal is absolute step #1 in beating hair algae, then nitrate and phosphate support ideally as weekly giant water changes 3x your normal workload, or a reduction in fish and feed bioload, or installation of better mechanical support or pad filters (binds phos/no3
) or some combination of all the above and I personally guarantee you hair algae will not get your tank anymore.
You can also cheat and install a large UV
filter but it will not kill gowing algae, only the repopulation after a manual removal of all traces. The fact it kills some plankton is not critical, reefers are feeding their corals and circumventing the natural feed web. Not that a reef tank produces anywhere near enough plankters to sustain corals alone, so killing some off if you'd rather see hair algae gone is a fine trade off in bad situations too.
Keeping a UV
filter on a tank is no different than running a bare bottom tank, the BB tank is extremely low plankton production, even worse (for the argument) because it's long term, UV
can be periodic
sometimes burning off the patches when you drain the tank for a large water change is a nice way to get in the nooks and crannies.
There is nothing wrong with UV
I have seen it work time and time again for years but there are many natural ways which I recommend. Notice I didn't mention clean up crews.
Thats focusing on cleanup, after production, whereas no cleanup crew shows you the pure primary production trends of the system. Sometimes doing things in reverse works strangely
Not everyone agrees with such bioload control, they'd rather have diverse fish life and use powerful skimming mainly to support the tank, or a large refugium to do the work. You can start with utmost bioload restriction first which will kill it off the fastest, and then loosen up as you rework the balance of the tank.