regarding the riding it out method.
The problems i have encountered when trying out this method is, you dont know how long you are going to be riding out this part of your tank maturity faze and during this time I have lost quite a few corals and frags due to algae smothering them.
The tank looks hidious. You feel helpless and beaten.
I have spent up to 20hrs a week even more cleaning it out for it to grow back within a couple of days.
I believe while the nutrients are in the water for these algaes to thrive they will.
So you need to ask yourself, i have high nutrients in my water, why?
There are many many ways phosphates and nitrates enter our systems, and a quick google search will explain this in detail, a few of the main reasons have already been mentioned by other reefers here.
Now if you can not pin point the reason as to why? which was me at the time, then you just roll with it, you say to yourself, so i have high nutrients and a shit load of algae, so i need to get rid of the algae, but i need something else to obsorb all the excess nutrients so the algae doesnt grow back.
So to get rid of the algae, I water change, this will bring nutrients down in your water, if you are mixing your own ASW, use RO and high quality salt or you will just be putting more nutrients back into the tank making your hard work pointless. Just after doing a 50% water change I light starve, algae NEED light to thrive, deprive it of this.
So you have just taken most of the nutrients out of the water and are starving the algae of light, which are the main things algae need to grow. I do another 50% water change 4-7 days after the first 50% change to really get the water super low in nutrients,
Once you have removed the algae from your tank, you are going to need something to obsorb these nutients to stop the algae from returning, once again there are many many methods to accomplish this, IMO a refugium is a great start.
I am not saying riding it out wont work, it definatley would, its just that i was loosing corals and stumbled across the method i use now, and for me has worked out to be my quick algae response program.
Good luck
p.s dosing magnesium will help your situation