You may not want to dry out the silica gel completely. If you are displaying metals, the lower the RH the better, but if it’s wood or paper or textiles, the RH shouldn’t be under about 35%. Before you put anything in the cases, you should put in the silica gel, let it acclimate, and measure the RH. Even with very dry silica gel, most cases aren’t very air-tight – and even well-sealed Plexi or glass vitrines leak on air exchange per day, so that’s why you need an independent reading of what the RH really is.
