two, six by thirty five just ask when you buy i sell them at 100.00 each approx will take half a sack in each one. use one to fill the tank one to polish with after the pump .when your polish reads 006-010 remove and use this di to fill the water into the tank then change the one that was filling the tank with new resin this become s your polisher ,
if that makes sense you will get a lot more life out of your resin most my customer s will get 12-14 tanks of water say a 350 liter tank in areas of at least 295-350 on the tds scale , for them they say that for every £100. earned its cost them £3.00 in resin not bad for an exhaustable product
tony 07944 227635 if you want to have repeated