Boveda will never humidify beyond the RH on the pack, so there’s no such thing as “too much”. You want to think in terms of using at least the minimum because the more you use, the more efficient Boveda works and the longer they last. You’ll know it’s time to replace when the entire Boveda begins turning hard.
Simply place the correct number of Boveda inside your container to maintain a precise relative humidity. Each Boveda consists of a specially prepared saturated solution of pure water and natural salt. This saturated solution is contained within a water-vapor permeable “reverse osmosis” membrane. Within a closed container Boveda maintains a predetermined level of (RH) by releasing or absorbing purified water-vapor, as needed, through the membrane.
Boveda provides the cleanest and most purified humidity of all other products available on the market today.