I keep several Mexicans in the refugium and whenever I see hair algae toss them in the display tank and repeat. Urchins are a different issue as they are a lot harder to pull out so probably best you stick with the Mexicans.I decided to exchange 6 of the massive ones I bought, and keep the 4 small urchins.
Those big urchins will cause me not to sleep at night lol.
Hopefully there will be some changes around Miami’s reef lol.