RO water issue

[vangvace]

It was kinda talked about already, but the reason to test pre-DI is that a new DI filter can absorb quite a bit on it's own and can mask a dieing membrane or used up prefilters.

How would I test pre-di ? Mine doesn';t seem to have a bypass or anything.

Without the bipass it's a small pain, but...

Depressurize the system by making a batch of water and turning off the source water. Open the contain that holds the DI cartridge and remove it. Replace the now empty container and make water as you normally would.

This is assuming you cannot easily get to the fittings going into the DI unit.