I just finished using Ployblend Grout Renew manufactured by Custom Building Products, basically making the grout uniform in color. I'm happy with the results. Question for those who know: should I put a sealer over the grout and tile? The ceramic tile is 50 years old and in very good shape. The Grout Renew is advertised as an all-in-one colorant and sealer, therefore I'm questioning the use of anything else. Also, the manufacturere recommends a neutral cleaner. Suggestions needed for what is considered a neutral sealer. Thanks!!!!

If it says that it's a sealwer, no you shouldn't need anything else.
Water is ph neutral.
You can also buy their fancy ph neutral cleaner, but water should be all you need. If you have a heavy problem area, a little vinegar mixed in on occasion won't hurt.