Purple algae

[gremelp]

I’m new to the saltwater reef aquarium world. It started as a birthday for my 6 year old daughter. Boy wish I knew what I’ve learned so far before I started. I’m committed to it now through stubbornness of having my 55 gal tank leak twice, both times losing about 25 gal. Saved the fish in both cases & have managed to now have kept a leak less tank going for about 3 months now. I perform 20%water changes every 2 weeks. My coral has developed a purple algae & also on the glass. I clean the glass when I perform my water changes. My ? is should I allow the algae to grow on the coral. Is it signs of a healthy tank?

 

[lapin]

If we could get a picture it would help ID the algae.
Good job on the tank.... dead-i-cation