If the hair algae is really bad, the options IME are very limited.
Clean RO water buckets.
Test RO water with TDS meter in the bucket that you are about to add salt.
Turn off lights - like mentioned above.
Remove sandbed.
Cook liverock.
Clean skimmer several time per week.
Keep Alk & PH levels up.
Run phosphate remover.
Feed fish less.
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I feel your pain.
If you don't have much hair algae -
skip the cooking live rock and removing sand bed.