TAC or “template assisted crystillaztion” is a newer technology finally gaining ground in the United States and I am looking for a source here in Mexico. It does not need to be backwashed and does not put salt into the sewer like the traditional softeners with brine tanks. So help me out if you find a source for TAC. TAC originated in Germany and was tested by Arizona State University in April 2011. The link below is to a .pdf file with a power point presentation of the testing structure and the results of several technologies. TAC came out on top for the lowest scale deposits on a hot water heater coil. Also below a link to a nice explanation of TAC.

Hot water heaters pay the biggest price from scale build up but we all know it is the clogged shower heads and the plugged up low pressure on the sink faucets that annoy us the most.

Low Cost Alternatives: take off any shower heads and aerators (those little screens screwed into the spout of your faucets) and soak in vinegar overnight. Scrub with a brush and replace. You can tie a plastic bag with vinegar on the faucets and the shower heads you cannot remove. Wrap a rubber band around the bag to seal it and get some of the fixture soaking in the vinegar. Remove the next day (or wait 2 or more days if you can) and scrub with a plastic brush.

Here is a link about TAC, a nice explanation: https://www.e-tankless.com/how-TAC-works.php
Here is the study from ASU: https://static1.squarespace.com/static/56251170e4b095e786b34523/t/565ddd7ae4b0d522090423ba/1448992122459/AlternativesIonExchangeSofteners_April2011.pdf