the tiny ones, there’s just not much room for resin after the reduced tank height
in other words, the top and bottom of the tank still take up ‘x’ amount of height whether its a 1.5 or .75, so the .75 is half the height of a 1.5 but a 1/4 (or therabouts) of room in the tank for resin in the reduced height. (at least the ones I had)
You will be very happy you got the 1.5. It will last you a long time and changing DI tanks out takes time away from work. You must be using Semens as that is price is great. Another advantage to the big tank is you do not need to worry about high water pressure. With the small tanks that can cause the tds to be to high. The reason not to use your tank laying down is what is called channeling. The water will channel at the top of the tank and it does not get proper time in the resin to remove the tds. Strap it to the inside of your van in a upright position that is safe and secure Hope this helps feel free to call if you need any help 865 3100728
Thanks for the info John! I’m on the fence about the big tank but you make a good point-- I won’t have to mess with it for a while especially if I have an average TDS of 30.