UV systems are basically sized using two and sometimes three parameters. 1) The maximum flow rate of water that will be flowing through the UV. 2) The size of plumbing connected to the UV. 3) The degree of color in your family’s water. So let’s look at each one of these: 1) If you don’t know the maximum flow rate coming from your well or lake pump you can calculate it by following the procedure outlined in this video https://www.youtube.com/watch?v=BONHr... You need to make sure that you don’t buy a UV system that is rated for a lower flow rate than your pump is producing. 2) If your plumbing is ¾” you need to make sure that the UV you are connecting to your plumbing is at least ¾” other wise it will slow down the flow of water to your whole house. 3) If there is color in your water from organics (tannins) you either need to remove the color altogether or if it’s minor and it doesn’t bother you otherwise you can just over size the UV system to make up for the loss in UV transmittance from the color in the water. How do you know what % of UV tansmittance is getting through your water? You can always send me a sample and I can test it with my UVT meter. Please share this video https://youtu.be/6w8LG-KnUkk For more great information about water treatment subscribe! https://www.youtube.com/user/WaterSto... Follow me https://www.facebook.com/TheWaterEstore/ https://twitter.com/FilterEstore https://www.linkedin.com/company/the-... or email info@TheWaterEstore.com or info@TheWaterStoreMidland.com Check out our online store at TheWaterEstore.com or our full service store in Midland, Ontario at TheWaterStoreMidland.com Mail Water Sample to: Water Store Midland 1004 King Street Midland, Ontario L4R0B8