Did you leave the filter media intact? If not, the tank will likely cycle again--just something to watch for.
As for algae. There are several things that can cause algae to take over, and regretfully, substrate is seldom on the list. Bleaching the decorations won't help--the algae likely comes in with the water. Certain types, like black beard and hair algae, are often introduced on plants, but the common, green fuzzy stuff is actually in the water source. An abundance of light, and lots of nutrients in the water are the usual problems.
If this is a planted tank, reducing the watts of light may not be advised, but you can limit the light to 8-9 hours per day. Plants don't need more than that. Nutrients are another story. Most commonly, over feeding or over fertilizing is to blame. Over feeding leaves lots of phosphates in addition to the nitrogen source--doesn't help the plants much, but feeds the algae. Fertilization is something that requires a great deal of attention, not only to what is being used, but also to the dosing schedule. And, of course, plants must have CO2 to use the available nutrients, while algae is more oppurtunistic and can thrive without as much CO2.
Before making any suggestions, please indicate how much light you have (watts and hours), what fertilization happens, if there's supplemental CO2, how often are the fish fed, how many fish are there, and how often do you clean the tank?