How long is too long?

One of the main questions we are asked is "when to change filters on UV filtration systems?".

And sometimes we (the cartridges) are accused on not working (when they block up)!

Simple answer 1: For filter systems that do not have UV, change them annually (if they last that long) because over time they build up bacteria etc, and without UV to sterilise those 'living nasties' you are increasingly being at risk as time passes.

Simple answer 2: For filtration systems with UV protection change the cartridges when they plug (block up sufficiently to reduce your shower pressure too much).

Simple answer 3: For UV systems change them every 6 months so that when you change the lamp annually you 'automatically' change the cartridges at the same time.

WARNING: Older UV systems that do not have a digital countdown alarm (for lamp life) are a potential hazzard because...the lamps keep glowing long after they have lost most of their sterilisation power! So if your cartridges don't easily plug and stay in for more than a year, you are introducing living nasties that will not be sterilised!

Some of detail...

Cartridge life is completely dependent on the quality and amount of water your system processes and the type and rating of filters you use.  In simplistic terms each filter has a Micron rating which indicates its density and therefore the restriction that it presents to the water wanting to pass through it. We find that the ideal (average) most popular filters used are 1 to 5 Micron. So a system may have a 5 Micron Pleated paper for the sands and sediment. A 5 Micron Carbon Block filter for taste and odour and a 1 Micron polishing filter for fine sediment and water discolouration.  This configuration is the most common and offers on say roof to tank water systems around 6 to 12 months between replacement. Outside factors can reduce this duration for example pollen will block filters very quickly. Bore and stream water systems require different configuration, ratings and types of filters. As there are so many variant’s with these water sources we need to individually discuss these with you.

Increasing the Micron rating of your filters will increase the service interval but we caution you with two points. Firstly a less dense filter allows more contaminates through and secondly if the turbidity (clarity) of the water isn’t correct you may affect the UV chambers ability to kill the bacteria in the water. So in short old contaminated filters or incorrectly specified filters will result in the bacteria (if present) hiding behind those unfiltered particulates as they pass through the chamber shielding the UV light and preventing sterilisation.

Most people have a 2 or 3 filter system. In these cases the first filter is normally a pleated paper filter designed to remove sand and sediment from the water. This filter takes out the bulk of the contaminants and is washable. In most cases clients don’t tend to bother but removing this every say 3 months and giving it a wash with the hose will extend all the filters life and help with system blocking.

Another item that is inexpensive and will greatly help with blocking filters is a RainCatcher. This is a double filter bag filter (500 micron mesh then 100 micron bag) which sits in the entry to your water tank. The mesh removes all large contaminants from the water (rodents, leaves etc) and the bag helps with pollen and finer silts/mud. Easily emptied and washed the RainCatcher helps considerably with extending system filter life, and almost entirely eliminates the need to empty and clean the tank.

After 12 months of continued use filters become impregnated with bacteria and start to dramatically reduce pressure. Using filters past this time defeats the purpose of the filtration system as it will not function correctly, and introduce risk.

Based on the volume of water processed and what they remove, the cost of the filters is not high (at $27 each plus gst). So a 3 filter system will cost around $81 plus gst every 9 to 12 months, not a lot when you consider what you get. So our advice is if you spend what is a reasonable amount of money on a UV system to protect yourself and your family; change the filters regularly, and it will do the job you purchased it to do.