Kettles - Metal Bits And Brita Filter Questions

[zuulan]

Hi All

I've had problems when I've added boiling water to cold water before doing a water change. I've seen little white dots float on top of the water, which only appear after adding the boiling water. So I assume it's something metallic from the kettle. I had this problem before on a cheap kettle, so I threw that out and bought a more expensive brand. 6 months later and it's back.

As anyone else had this problem before? What is it and is it harmful to the fish?

I can net the dots I see on the surface but I think the same exists under the surface which isn't easy to see.


On another related topic I've just bought another kettle and it's a Brita one with a filter on it. See link here.

My question is, has anyone used these before in their water changes. Is it better for the fish, no effect or harmful in any way??

 

[StandbySetting]

The white stuff is most probably limescale that has formed on the heating element in the kettle.

 

[Essjay]

I wouldn't use water that has been through a Brita filter, whether it's a jug or a kettle. I have a Brita jug, so I tested the water immediately after it had run through the filter and compared it to freshly run tapwater. The filter dropped my pH from 7.2 to off the bottom of the scale (somewhere below 6.0), the GH from 9 to 6 and the KH from 4 to zero.

 

[zuulan]

There's no limescale in the kettle, also water in this area doesn't suffer from limescale. Any other ideas?

Thanks for the info on the Brita filter, I'll remove the filter before boiling water for the tanks.
At least I know it does do something and they are worth investing in for drinking water.

 

[Bugdozer]

I just ran a pH test on some filtered water from my kettle's Brita filter. I can also confirm it dropped from its natural 7.5 to 6 or less. Be careful. Interestingly, this means the filter must be adding something into the water when it takes out impurities. And then I'm drinking it...

 

[StandbySetting]

It's possible that the water still contains CO2 from the tap, I'd wait 24 hours and test again to see if it rises.

 

[cornclose]

Most methods of measuring pH of water that contains very few if any dissolved solids are innacurate and will always produce results around pH 6.0 or less. This doesn't mean it is this acidic, all it means is that as there are no disolved minerals to react against in the water, the pH readings are skewed.

The same phenomenon occurs when you measure the pH of RO water.

 

[Bugdozer]

Most methods of measuring pH of water that contains very few if any dissolved solids are innacurate and will always produce results around pH 6.0 or less. This doesn't mean it is this acidic, all it means is that as there are no disolved minerals to react against in the water, the pH readings are skewed.

The same phenomenon occurs when you measure the pH of RO water.

How come measuring the pH of distilled water in GCSE and A-level chemistry classes always delivered a pH reading of 7 then?

 

[cornclose]

That's exactly the point - most test kits use a certain method to measure the pH which relies on the water being tested to have some dissolve solids in it for the reagent in the test fluid to react against.

Without these dissolved solids, the typical water test kits will result in pH 6 or lower (most test kits aren't able to measure below pH 6 anyway so that's why a lot of them bottom out at 6). This doesn't mean the water *is* pH 6, it just exposes a flaw in the method of testing.

There are many ways of testing pH from reacting with other chemicals through to EMF methods. They all have their advantages and disadvantages with accuracy and resolution which can vary greatly.

If you want a true pH reading to repeatable lab standards, then you'll need £x,000's or even £xx,000's to do it properly.

 

[Essjay]

The pH of pure water at 25C is 7.0


This is from Brtia's website here http/www.brita.net/faqs_household.html#24

Ion exchange resins exist in the form of cation exchange resins and anion exchange resins. The BRITA water filter cartridge is filled with cation exchangers. These replace positively charged ions such as calcium, magnesium, lead or copper with positively charged hydrogen ions.

pH is a measure of hydrogen ions. The more there are, the lower the pH. As explined in Brita's website, the cartidges remove postively changed ions and replace them with hydrogen ions, ie the cartridges increase the amount of hydrogen ions in filtered water - that is they lower the pH.

 

[Bugdozer]

The pH of pure water at 25C is 7.0


This is from Brtia's website here http/www.brita.net/faqs_household.html#24

Ion exchange resins exist in the form of cation exchange resins and anion exchange resins. The BRITA water filter cartridge is filled with cation exchangers. These replace positively charged ions such as calcium, magnesium, lead or copper with positively charged hydrogen ions.

pH is a measure of hydrogen ions. The more there are, the lower the pH. As explined in Brita's website, the cartidges remove postively changed ions and replace them with hydrogen ions, ie the cartridges increase the amount of hydrogen ions in filtered water - that is they lower the pH.

That makes sense. For example, a magnesium sulphate molecule would become a sulphuric acid molecule. Lead nitrate would become nitric acid. Rise in acidity explained!