I would first check which marker elutes at the wrong volume: PD should elute in the total volume (around 150 ml) and BD in the void volume (in general about 1/3 of total, so 50 ml). If one is OK and the other wrong, I would try another marker for the wrong one. If both are wrong, or if they diffuse too much (that is if you recover the dye in more than 15-20 ml, it might be the packing. The trick with the packing is to prevent irregularities in the resin bed. To do this, the ideal way is to have a reservoir above the column so that you can pour all the resin that will be necessary for your 150 ml (probably around 300 ml) in one shot. If your column is homemade, you probably don't have a reservoir. So flow a little water through your column first to wet the frit, remove bubbles and close the bottom tap keeping 2 cm water at the bottom of the column (to prevent the resin from clogging the bottom frit). Then thoroughly resuspend the resin in your bottle to get a homogeneous slurry. Slowly pour your slurry down the column (ideally with a pipet, moving it in small circles so that the slurry drops do not fall all on the same spot). Completely fill the column. Open the bottom and start a slow flow-rate. You should see the horizontal separation between the packed bed (more opaque) and the slurry (more transluscent) appear rapidly and move slowly upwards. At the same time, there should be a separation at the top between the slurry and the liquid. Keep adding slurry slowly, always by pipetting in slow circles close to the surface until the packed bed reaches the desired height, always avoiding to perturb the surface of the bed. After that, lower the top adaptor close to the bed, run two column volumes water through the column at the standard flow rate, and one at the maximum flow rate. Lower the top adaptor until it slightly enters the packed bed, tighten the O-ring. The column should now be ready for use. Good luck!

I agree with Sebastian Schmitt about reversing the flow for cleaning, because the issue almost always will be at the top of the column. Also raise the adapter a few mm to allow the bed to expand when in reverse flow. The standard recommendation from the supplier is to use 200mM NaOH (I've not seen acid used before). Try at least 2 column volumes in reverse flow and then switch to water. Finally switch back to normal flow direction in water, adjust the adapter as required, and check the pressure. If all is well, re-equilibrate with your column buffer. If NaOH doesn't work you might need the more aggressive treatment with guanidinium hydrochloride as suggested above. If you are still having issues after all this, you may need to remove the top 2-3 mm of resin.

Please look at the following below links which may help you in your analysis:

https://www.scientificlabs.co.uk/handlers/libraryFiles.ashx?filename=Technical_Data_Sheets_1_17059901_A.pdf

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7121854/

Thanks

Is there enough stability between Gaunidium hydrochloride solution and sephercal matrix Sebastian Schmitt