UV question

[jgaspar]

Greetings to all

I'm about to install an undercounter dual filter with a 5 micron sediment and a KDF/GAC cartridge, the water is from a private well, due to bacteria concern a UV unit is also to be installed

It´s better to install the inline UV unit between the sediment and KDF/GAC cartridges or after the KDF/GAC?

TIA

[Joseph Meehan]

I would always put it last, so it can work on anything that might decide to grow in any of the filters.

[RB]

Place the UV sterilizer after the filters. What will happen if you have particulate matter in your water is that it will coat the UV tube (or its quartz protective sleeve) so that in time the UV dose to the water is reduced below an effective level. Placing the sterilizer after the filters slows this but doesn't prevent it.

UV sterilizers need to be cleaned periodically to remove any build up on the sleeve.

I run a series of filters ahead of my UV sterilizer. I start with a 100 micron filter, followed by 25 microns, followed by two 5 micron filters in parallel, and then two 1 micron filters in parallel. I can run for about 9 months before cleaning the quartz tube. I replace the UV tube about every 12 months.

In my opinion UV filters can give the user false confidence. A minimum UV dose is needed to disinfect. This is a combination of the flux from the lamp and the dwell time that the water is in the sterilizer. As the lamp ages or becomes dirty the flux level drops and after a while, even though the sterilizer is "operating" it isn't disinfecting. Some of the better sterilizers monitor the dose delivered and warn the user when the system requires maintenance. Others don't.

RB

[e-mail] wrote:

[jgaspar]

Thanks

Some users say that we should use a desinfection system ( like UV) before the carbon filter as bacteria can grow on carbon.

The well tested negative for coliform bacteria, but I´m adding the UV just in case.

I will install the UV unit After the sediment and KDF/carbon filter as suggested.

João