Dramatic pH drop in filtered H2O?

[khyberkitsune]

I picked up a fresh Brita water filter yesterday, and have been using it to do some minor water treatment. I noticed something - the pH drops from about 8.5 to a near-perfect ~5.8 just going through the filter.

Does anybody else experience this? I typically just use straight tap but I'm willing to roll with a water change, and at least filter it before adding nutes. Looks like if this keeps doing what it does, all I have to do is add nutes after filtering, no pH down required!

[Daddynobucks]

That seems like a big drop,and to 5.8 seems even stranger.You are using a meter right? not some test papar strips. those papers are so EASILY contaminated.

What was your last filter puting out for Ph? Let us know what it does after 20-30 gal of use.

Daddy

[khyberkitsune]

That seems like a big drop,and to 5.8 seems even stranger.You are using a meter right? not some test papar strips. those papers are so EASILY contaminated.

What was your last filter puting out for Ph? Let us know what it does after 20-30 gal of use.

Daddy

I use liquid reagents for pH testing. I don't use paper, and meters require constant calibration.

I wasn't using ANY filter, at all, ever, until now.

[cigarettes42]

i agree with daddy. its your testing equipment. get a good ph meter and ditch the liquid. ph meters will last a long time if you take care of it. i have a hanna (which i dont like) that does the job and i only had to recalibrate it once in 2 years. the calibration solution is cheap too. probably $3 for both ph4 and ph7 calibration fluid. temperature of water can screw up test strip or liquids because they dont have a temp compensation built into it.

[LOC NAR on probation]

Agreed.

Bro uses a britta and it only drops his tap water .02 or so.

I have 2 R/O filters and the water is almost the same after. 7.0 before and 6.8 after.

I have a hanna combo that needs the ph probe replaced for the scound time but 6 years old. Now I use a cheap milwalkie but they work very well and last as long as you don't drop them in water. And I know when it needs calibrating by always checking the R/O, it never changes.

[khyberkitsune]

So I broke out the rest of my chemistry set and did an analysis.

Brita's special filtration resin removes calcium and magnesium ions and replaces them with H+ hydrogen ions, resulting in the acidic pH of filtered water. It does not remove carbonates, which are now present in excess as HCO3-. If I were to boil this, my pH would go from 5.8 to a likely ~10 because the CO2 gas would split, leaving OH- ions in place which would cause the rise in pH.

[Daddynobucks]

that makes perfect sence

one ques. is the resin an ION exchange resin and does it use Na in the exchange?

Daddy

[khyberkitsune]

that makes perfect sence

one ques. is the resin an ION exchange resin and does it use Na in the exchange?

Daddy

Yes, it is an ion-exchange resin, but given that it also works as a metals filter, I don't think it's using Na. Besides, typical purified Na is reactive with water.

[Daddynobucks]

yep pure Na is a no no with H2O, in the resin its bonded with ?? di-alkyl?? what evers. but some Na does get loose as a salt of some type and can screw with K uptake. not that Britta uses this type resin
if you have a GOOD chemistry set:) you can check for Na in the filtered water.

I think I'll pick one up and do some comparing, I now use a hydro-logic Cl/chloramine filter

Daddy

[khyberkitsune]

yep pure Na is a no no with H2O, in the resin its bonded with ?? di-alkyl?? what evers. but some Na does get loose as a salt of some type and can screw with K uptake. not that Britta uses this type resin
if you have a GOOD chemistry set:) you can check for Na in the filtered water.

I think I'll pick one up and do some comparing, I now use a hydro-logic Cl/chloramine filter

Daddy

Practically nil Na in the water after running through the filter, going by taste alone.

[CovertCarpenter]

... yeah, sounds kinda weird, but it also sounds like you chem-types have sussed out what seems to be the likely cause.

I use a Brita almost exclusively, and with my own (GH-labelled) Handy-Dandy Liquid Cheapie PH Test Kit, it seems like the water coming out is virtually the same as what's going in (around 7.0 here in TO).

Gonna test my raw Brita water again tonight, just to make sure I'm not on drugz. Well, other than that /one/ drug ;)