Water filters and ph

[ConqueringLOJ]

Ok, So for my grows, I use water that has been filtered (like most here do) to get rid of particulate, heavy metals, and the chlorine that is found in most tap water. I have two different filters that I have been using: One is a Brita filter, and the other is from the dispenser on my refrigerator that makes filtered ice and water. Both of them are charcoal filters and use the same water source, but I have noticed that they output water that has a very different PH.

Both filters are fairly new.
My unfiltered tap generally measures between PH 7.5 - 8.0
The filtered fridge water is measuring a similar PH 7.5 - 7.8
The Brita filtered water measures between 6.0 - 6.5

Has anyone ever noticed a similar occurrence? Is the Brita the odd ball for lowering the PH so much?

Anyway, it's not a big deal as I make sure to adjust my PH accordingly and my plants are all happy and healthy. I just thought it is kinda weird to see such a big PH swing between different filters.

 

[SteveHman]

Maybe the Brita has some buffers added to it? I've never done a test on mine before and after filtering. I have one of those big-ass cartridge filters that I use to filter my brewing water and also for the moms. I use R/O on the hydro. I'll test before and after when I water tomorrow to see if there's a big difference.

I need to buy an R/O system soon.

 

[ConqueringLOJ]

Thanks for the reply stevehman! I'd be interested to hear what your findings are if you do decide to test the filters you use.

 

[TorturedSoul]

Is the Brita filter the style that goes on the kitchen faucet spout in place of the aerator? If so, when you first install one you have to run it for 5(?) minutes to flush out the loose carbon dust. Perhaps they allow trace carbon into the filtered water and it lowers the pH?

I don't know if they release carbon after the initial flush, and I don't know if such would affect the pH. Just wondering.

 

[SteveHman]

OK, this sounds really odd but here are the numbers I took on my water yesterday when I watered the moms.
Tap Water: pH 7.02, PPM 487 (yes, I know I have hard water, S.D. County is known for it)
Carbon filtered through large cartridge: pH 7.18 PPM 504

pH and PPM both went UP after filtering? I just replaced the cartridge a couple days ago, so it may be some carbon particles adding to it. I will flush it for 5 minutes (like TS mentioned) and give it another test when I water Monday.

 

[ConqueringLOJ]

Is the Brita filter the style that goes on the kitchen faucet spout in place of the aerator? If so, when you first install one you have to run it for 5(?) minutes to flush out the loose carbon dust. Perhaps they allow trace carbon into the filtered water and it lowers the pH?

I don't know if they release carbon after the initial flush, and I don't know if such would affect the pH. Just wondering.

Hey TS! Thanks for the reply. Actually the Brita filter I use is built into a 1gal jug. It is the kind that you can store in the regrigerator. The filter I used to test wasn't brand new, it had a good 5-7 gallons run through it already. But perhaps you are right, maybe there are trace carbon particles escaping into the water. Hmm?

 

[ConqueringLOJ]

OK, this sounds really odd but here are the numbers I took on my water yesterday when I watered the moms.
Tap Water: pH 7.02, PPM 487 (yes, I know I have hard water, S.D. County is known for it)
Carbon filtered through large cartridge: pH 7.18 PPM 504

pH and PPM both went UP after filtering? I just replaced the cartridge a couple days ago, so it may be some carbon particles adding to it. I will flush it for 5 minutes (like TS mentioned) and give it another test when I water Monday.

Yes, very interesting that the PPM went up. Also, that the PH went up. Please do take some more samples when the filter has been 'broken in' a little bit more.

This is turning into a head scratcher for sure!

 

[garce]

My tap water comes in a 8 ph ... after Brita it's 6 ph ... my only concern is that i have read where
a lot of filters remove calcium and mag ... no problem , i can add some calmag , but need to know
if the filter doesn't touch them ... i never want to over nute again ..
BTW ... as far a chlorine goes , just leave the water in a open container overnight ... cl leaves water
very quickly ... garce

 

[TorturedSoul]

I like having a little calcium in my tapwater. That way, I can supplement with epsom salt instead of having to purchase a more expensive calcium/magnesium product. Unfortunately, my tapwater doesn't contain a little calcium, lol. I sometimes think there's enough in our water for any leaky plumbing to be self-reparing, lol.

BtW, some nutrient manufacturers offer one (or more) of their components in a "hard water" version for those who have less than stellar tapwater (and who do not wish to use a filter or buy water at the store). General Hydroponics three-part Flora series comes to mind, but (IIRC) there are others, I think.