well water

here in a few months ill be moving to a place that has either city or well water. i have a RO/DI unit. it im useing well water how often should i change filters and what should i be testing for?

 

You need to check the hardness of the well water. If the hardness is more than 1 (grains per gallon), you will need a water softener or you will ruin/clog your membrane fairly quickly.

 

so what happens when the hardness is out of control?

 

Won't salt be just as bad? They use RO membranes for desalination.

I think using a flush kit every month will wash away the calcium and make the membrane last.

The Iron will clog up the pre-filters faster. But, they are relatively cheap. Once they start changing to a yellow/brown from the iron. Change them out. Inline TDS between the pre-filters and membrane will help let you know when they are going.

 

Flush kits are a waste of money. All they do is lighten your wallet and give you a warm fuzzy feeling, they have no proven documented value. Once calcium gets on the membranes surface and sits for any length of time it begins to solidify and no amount of flushing in the world will remove it short of chemical cleaning.

All membrane manufacturers recommend softened water regardless of the source. 1 grain of hardness is a little extreme for a starting point since thats only about 17 ppm hardness. 5-10 grains of hardness is starting to get hard.

The best things you can do for any RO or RO/DI system regardless of the usage and source is to change the sediment and carbon block filters every 6 months using high quality, low micron replacements and disinfect the system while you have it down. Make sure the waste ratio is at 4:1 as measured with a measuring cup and clock or watch since this is what really flushes a membrane and keeps it fresh and always use the system at least every 10-14 days and store it in a climate controlled area away from direct lighting and temperature extremes.

The only thing you can reliably test for with a RO/DI is TDS or conductivity. Make sure to monitor the tap water, RO only before DI and final permeate or RO/DI TDS. With the first two numbers you can calculate the rejection rate or removal efficiency to determine the membrane condition.

 

thank you for the info.