A few years back, I purchased some Solv-Tek solvent purification systems.  They have since gone out of business (at least as far as I know).  My ether system is acting up.  I get plenty of pressure in but nothing out.  At the top of the second column there is a small filter which I have cleaned out by blowing nitrogen through (that was a trick I got from the company before they disappeared).  That trick didn't work.  There aren't too many other troubleshooting options that I am aware of, so I think I have to take the columns down and refill them.  I have some details on that procedure, but not a lot (for example, I use alumina in one column but no clue as to the size).  If anyone out there has any suggestions, I would sure appreciate some ideas.