maintenance for undersink uv filter

[jeremytl]

I decided to bite the bullet and install at least something for killing bacteria. I have run all tests, bacteria is the only thing showing up (not eColi).

I'm currently getting quotes for under-sink filters to just filter the water to the cold tap, where we'll be drinking/cooking from. When I ask about what the maintenance is like, it seems that people sort of dodge the question. I can only assume that the maintenance is expensive or labor intensive? Whats the scoop?

[Gary Slusser]

You should do the treatment on a POE/whole house basis.

Depending on what and how much of it is in your water, like iron, hardness, H2S etc. etc. you may not be able to use a UV light as POU or POE (point of use or entry), or you will need pretreatment like a softener etc..

Otherwise UV is a good way to go unless your pretreatment requires chlorine or other disinfectant.

So get a water test for those things, expect H2S and post the results including the nitrate and nitrite levels.

BTW, UVs can have monitors to tell you if it is working correctly on not but you need to replace the lamp and clean the quartz sleeve every year regardless.

[jeremytl]

I'm still thinking of going the UV route.

Test results, all in mg/l:

Nitrite <.10
Nitrate 1.01
Alkalinity as CaCO3 119 (2 years ago Alkalinity as CaCO3 was 118)
Arsenic <.001
Calcium 55.4 (2 years ago calcium was 26.0)
Chloride IC 95 (2 years ago Chloride IC was 74)
Copper <0.05
Flouride <0.20
Iron 0.14 (2 years ago was <0.10)
Hardness as CaCO3 (Ca, Mg) 246
(2 years ago Hardness as CaCO3 (Ca, Mg) was 159)
Magnesium 26.2 (2 years ago Magnesium was 23.0)
Manganese <0.03
Lead <0.005
pH 6.6 (2 years ago pH was 6.9)
Zinc 0.06 (2 years ago Zinc was <0.05)

So what say you?

UV light the way to go?

[Gary Slusser]

Your hardness is way too high for any UV to work. Max hardness is usually stated as 7 gpg by most if not all UV manufacturers. And the iron doesn't help, but a softener will remove it.

I suggest a correctly sized softener using a Clack WS-1 control valve based on the number of people in the household, the number of bathrooms and type of fixtures in them so the constant SFR gpm of the softener is higher than your peak demand flow rate.