It is very much farm specific but generally, the order of chemical teat dips followGreat advice Martin , but our vet recommended a high % iodine pre dip and barrier post dip ! She felt it much better than lactic acid or Chlororhex dips ,when we had a cell count and mastitis problem (cells near 200 ,despite milk recording data help ,and this is despite us 6 months into using a Clusterflush - in our new to us parlour !
We also started using Bolshaws lime on the beds regularly ,and every time a cubicle has leaked milk on the bed mattress ! This along with nice dry pitch pine sawdust .
Cows are really clean too and although I worried about the lime drying the teats and wrecking the skin ,the quality Iodine dip seems to keep teats lovely and soft .
We also had a dynamic test on the new parlour ,which said the 65 35 pulsation A& B , was too sharp , so until we had that corrected in our SCR meters , we lowered our vacuum ,and we are typically are nearer 100 cells now , and have changed pulsation to 60 40 for gentler milking ,and upped the vac to 44 from 42 .
Not suggesting you have a machine problem ,but having had very helpful advice from our local Gea agent ,and the vet , culling the real culprits we seemed to have turned a corner !!
Good luck
iodine,chlorhexadine,lactic acid then chlorine dioxide . When you get on top of your mastitis problem and it settles down move back down the scale. Unfortunately a lot of people stick with the top spec dips because it works but you then have nowhere to go when the problem returns and the bugs have gotten immune to the chemical.
in your case you altered quite a bit so the iodine might well have been enough. I don’t think @Happy hillbily has said what dip is being used so maybe already a way up the scale?