hi there ive been sealing drives for 7 years now i use resiblock sealer the best on the market ,to seal the blocks need to be bone dry , i allow 3 good days for this , i dont put the kiln dried sand in the joints till the day of the sealing making sure no sand is left on top this normally requires a blower , also make sure there is no chance of rain in the next 12 hrs after sealing. the same process would apply to the cheaper sealants ....hope this helps
