PH MONITOR METERS

[crackmonkey]

Was thinking about buying one but don't really know how accurate they are, does anyone know? http/cgi.ebay.co.uk/BLUELABS-PH-MONITOR-...1QQcmdZViewItem

 

[Lateral Line]

That link doesn't work for me. Searching eBay for "Bluelabs" turned it up though. Odd it doesn't state the accuracy range - I would have expected it to have done so. Most "hobby" level pH meters are only accurate to about +/- 0.2 pH. Browsing eBay for pH meters, there were several others, many a good deal cheaper then that one.

The one I have is an old, but very high quality lab unit that I acquired when a company closed it's research labs near where I live. It is supposedly accurate to 0.01 pH. I'd hate to imagine what these cost to buy new - I got mine for 200 Kroner, about £18. Came with a spare elctrode and about 1000 sachets of calibrating buffers.

 

[George Farmer]

The one I have is an old, but very high quality lab unit that I acquired when a company closed it's research labs near where I live. It is supposedly accurate to 0.01 pH. I'd hate to imagine what these cost to buy new - I got mine for 200 Kroner, about £18. Came with a spare elctrode and about 1000 sachets of calibrating buffers.

[snapback]894760[/snapback]​

Lucky git

 

[Lateral Line]

I read in the local paper that the labs were closing, so a few weeks before they did, I mailed the company asking if they were disposing of any surplus equipment.

Their reply was they had already moved or planned to move the newer gear to their new premises, but that I was welcome to browse their "old junk".

All it took was noticing the story in the local rag and a making the mental connection. Anyone can do that. If you don't ask, you don't get. I would advise everyone here to watch out for news of closures or relocations which may involve the disposal of "useful items" of whatever nature.

Along with the pH meter, I obtained a number of items of laboratory glassware, a 5 liter bottle of Hydrochloric Acid, an illuminated bench magnifying glass, about a dozen retort stands with clamps and some electrical swichgear. Whole lot cost less then 500 Kroner, the retort stands and switchgear didn't cost anything at all. I suspect if I had not bought the other things, they would have gone into a skip, apart from the acid maybe.

 

[BigC]

Heres the one I use,
http/www.ultimateaquatics.co.uk/acatalog...g_Products.html
very accurate, but as said earlier needs to be recallibrated from time to time. Rather than buying small sachets of callibration fluids at astronomical prices, do a google for bulk ltr/gallon fluids from various sources, works out a whole lot cheaper.

 

[Lateral Line]

I'd just like to point out, that many "hobby" pH meters have a tight resolution, (it helps to sell them), as that one does BigC, but that is not a reflection of their accuracy. If a meter is only accurate to +/- 0.2 pH but resolved to 0.01, it is saying the water is between 6.89 and 7.11 which on a logarithmic scale, is quite a lot.

There is a huge difference between resolution and accuracy.

If you browse eBay right now searching for "ph meter" you'll find many. Of those that show the figures, look at the "resolution" and "accuracy" values.

 

[George Farmer]

I read in the local paper that the labs were closing, so a few weeks before they did, I mailed the company asking if they were disposing of any surplus equipment.

[snapback]894795[/snapback]​

Top tip. Cheers LL.

 

[BigC]

I'd just like to point out, that many "hobby" pH meters have a tight resolution, (it helps to sell them), as that one does BigC, but that is not a reflection of their accuracy. If a meter is only accurate to +/- 0.2 pH but resolved to 0.01, it is saying the water is between 6.89 and 7.11 which on a logarithmic scale, is quite a lot.

Point taken Lateral.