Problem with generic Kromasil C18

[Provetech]

Hi,
we are using Kromasil C18 column provided by a french society who pack the phase from EKA, it's the third column we buy and each time we get a pressure increasement at about 1000-1200 injection ex: 165b @0.7ml/min, 30-70 ACN-water. The column is fitted with online filer and c18 precolumn.
I wonder if the problem is the packing method or not, may i change my provider ?
Thanks

[Mark Tracy]

If you have a column with pressure too high to use anymore (nothing left to lose) try changing the inlet frit. If that solves the pressure problem, then the column vendor is not at fault. To prevent the problem, try a smaller-porosity pre-column filter; try more thorough sample filtration; try changing your pre-column more frequently.

If changing the inlet frit does not reduce the pressure, try changing the outlet frit. If that solves the problem, it may be a vendor-related problem.