Gardiner poles are great, I have the CLX 27 and 2 CLX 8 personal poles.
I have the twin 8litre set up from Window cleaning world. I find that having 2 tanks allows you to utilize your resin better as you can have the second tank as a back up. When the TDS starts to get high, bin the resin from the first tank, make the second tank #1 and then the new resin becomes #2.
They are advertised as being portable but with 16 litres of resin and water in them they do get heavy. Mine are now built into the van following 3 filters (10 micron, 5 micron and a 1 micron) I find this really helps the resin longevity.
Speak to Peter Erkin at WCW and he can set you up with a package. They are very good with delivery ( I’m in NZ) and Peter has a wealth of knowledge for this side of the world.