Lastly, there are different tools that not all places sell that could be better than others. As one example, Axeon makes a 98% rejection that removes almost all silica, or at least a lot more than other membranes. This can save a ton of resin, but if you just shop at one place you could be missing out. If your water has special needs, then call around and talk to the folks at Buckeye, AWI, BRS, etc. and see what they can offer.