EC/Ph meters - which to buy?

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Beth11
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EC/Ph meters - which to buy?

Hi All,

 

  I've gotten some really good advice on which EC or EC/Ph meter to buy, but I'm still up in the air.  My finalists are the blueray truncheon - ec only, no calibration, 5 year warranty.  The other is an Extech 500 that does EC and pH, requires calibration, a little more complicated, 1 year warranty.  Any final thoughts on which you'd pick?  I'm new to hydroponics, but can see myself getting sucked in to more complicated systems than the ag.  Here are the descriptions from amazon.com

http://www.amazon.com/exec/obidos/tg/detail/-/B000NI4AUA/ref=ord_cart_shr?%5Fencoding=UTF8&m=A26BRV88UWRLF&v=glance

http://www.amazon.com/exec/obidos/tg/detail/-/B0002NLKH2/ref=ord_cart_shr?%5Fencoding=UTF8&v=glance

 

Thanks,

Beth

 

 

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kitkat (not verified)
That's good to know.  I'm not

That's good to know.  I'm not exactly known for my patience. 

BB (not verified)
Glad to be of help. And

Glad to be of help. And another nice thing - the Hanna fits between the water level tube and the bowl so you can just stick it in there and go do other things for a few minutes. Holding it gets old real quick.

kitkat (not verified)
Thanks Bruce!  :-)  Both the

Thanks Bruce!  :-)  Both the EC and pH meters are on my wishlist.  I have heard great things about the Blulab truncheon, and now (thanks to you and Peat) I know about Hanna.  Thanks for the info.

BB (not verified)
Welcome, kitkat! That's not a

Welcome, kitkat! That's not a stupid question at all, I'm still coming to grips with it. I bought the Hanna pHep5 here , it's the same one Peat has and it is highly rated. I don't think temp has much effect on litmus paper or the PH drops but it makes a big difference in the electronic meters. I have no clue how the PH meters work but I see significant changes with temperature even though the meter has a temp probe and is supposed to compensate, and does, after a time. It eventually reads correctly after a few minutes or so with dipping and stirring at any reasonable temp but seems to love 25*C, it reads correct and stays there within 30 seconds or so. It has an indicator that's supposed to tell you when the reading is correct but it's nowhere near reliable without quite a bit of time and stirring, as you can read above.

The Bluelab truncheon takes a couple of minutes to read EC correctly so 2 minutes then a stir gives me good enough readings for both EC and PH that are repeatable. The drops are probably as accurate and quicker but a little messier. On a budget, I'd use the drops, in fact I still use them to verify a weird reading from the meter.

kitkat (not verified)
Hi Bruce, I have (probably) a

Hi Bruce,

I have (probably) a stupid question.  How does temperature figure into pH reading?  Are you supposed to take the reading at a certain temp, or over a certain range of temps?  I'm new to all this, and a pH meter is on my wishlist, but I want to have at least a basic understanding of what is involved before I run out and get one.  BTW, what model do you use?

Peat
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I'll definitely give it a go,

I'll definitely give it a go, just need to brew some water...

I know it's 7.01 but I figured the tolerance would take 7.00, not sure I have the patience to hold it for 7 minutes though.

BB (not verified)
Ah, but it's supposed to be

Ah, but it's supposed to be 7.01   but yeah, you could set it to cal at 7.0. I get varying readings with distilled water and having nothing productive to do, I finally got it to read 7.0 with bottled, distilled water as the water hit and passed 25*C, warming it by holding the cup (shot glass) in my hand and doing a lot of dipping and stirring. It's supposed to be temp compensated but I got indicated "good" reading from 7.6 to 6.8 as it slowly warmed up from 22*C to 27*C over ~7 minutes. Not great temp compensation, eh? Could you try that and see what you get?

I still don't know where that little glass tube came from and it's aggravating the dickens out of me.

Peat
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The only glass item on the

The only glass item on the probe is the pH measuring tip? Yours is intact so it's a mystery.

Talking about being a cheapskate, I was thinking I could calibrate mine on distilled water at pH 7.00 I have a de-humidifier, which I used to use in an old grow room, and that produces spot on pH 7 water with no EC - this stuff is perfect, as far as I know. I may not have to buy another bottle of pH 7 again..?

 

BB (not verified)
How strange, they brag about

How strange, they brag about their solutions being traceable back to a world standard. I bought the sachets because they were virtually the same price as a 250ml bottle and I wouldn't have to worry about contamination, I can be a slob at times. Looking at a 4.01 pack, the highest deviation they show is 4.20 at 95*C so I'd say you got a bum bottle. That doesn't inspire confidence.
 

I also had an odd thing happen today. When I took the cap off my meter I thought I saw something fall out and thought the sponge had dried and fallen out. It was there and everything looked intact so I did my routine and when done I put it back where I keep it, I found a tiny piece of clear glass tube, 3mm OD and about 7mm long with one end smooth and the other jagged, like it broke off something. It doesn't fit anything external on my meter and all my readings looked OK. After reading your post I checked mine with the last solutions I used to calibrate it (I'm too cheap to throw them away) it read 6.99 and 4.00 at 25*C. Now to figure out where that little piece of glass tube came from...

Peat
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Had something strange happen

Had something strange happen with my meter today.

I decided to do a full calibration 7.01 and 4.01, the meter would not calibrate on the 4.01 solution - kept saying WRNG on the display, basically it won't recognise the buffer. So, I calibrated on 7.01 only, checked the 7.01 solution afterwards and it read 7.05 - fine.

Checked the pH 4.01 buffer - it reads 4.63? No wonder the meter would not recognise it, so, dropped an e-mail of to Hanna today - I think I have a duff solution (I did have problems calibrating 4.01 all along).

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