Read the links in Tims post.. 🙂
Clado is a real bugger to treat, it's a very strong green algae very close to the plant family. Glut in normale dose wont kill it, you will actualy feed it same as you would feed the plants. Using glut as overdose spot treatment i'm personaly no fan of that. What does help in my experience is drasticaly clean out by hand as much as possible, than drain the tank as much as possible. Rub off removable hardscape with a hard brush. Spray peroxide over the affected areas and the hardscape you removed wait a 10 minutes. Put everything back, refill the tank with clean water, don't add ferts, followed by a 3 day blackout.. Absolute 100% blackout, no feeding, no peeking, fish can take it, most strong healthy plants don't care. After 3 day blackout do a maximum water change again. 90% of the algae will be gone, the clado still present likely is grey/lightgreen in color and dead and shrimp and fish food.
From there revert back to Tims post.. 🙂
If you don't it'll be back.. Clado is the Arnold Zwarzenegger among the algae..