Tue, 2009/01/27 - 6:06pm
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/-/B0002NLKH2/ref=ord_cart_shr?%5Fencoding=UTF8&v=glance
Thanks,
Beth
Wed, 2009/01/28 - 3:15am
#2
Hi Beth, welcome! I can definitely relate to getting sucked into other things...
No doubt about it, go for the Bluelab truncheon. Looking at the other, better seller from your Amazon link you can get one for $121 shipped which is a great price. It's head and shoulders above any of the others and never needs calibrating or new electrodes ($$$), plus it's waterproof and almost indestructible.
For PH, get one like this for $6 or so. It'll last a long time. Buy local, shipping doubles the price.You can find them lots of places - pet shops (aquarium supplies), hydroponic stores, plant nurseries, etc. I'd love to have a fancy electronic one but even I can't justify the price and upkeep.... Yet. 
Wed, 2009/01/28 - 1:07pm
#3
Personally Beth, I would buy separate models for pH and EC - if the Extech 500 broke down then you would lose both ways of measuring.
I have always used a Bluelab and I have never had any problems with them, you will find nothing but praise on the internet. Whatever you decide to buy, make sure it does EC, forget ppm as it's a pain to work with. It's not clear whether the Extech does simple EC (the manual is available if you click on the Extech 500 link above, page 5 for the display readout on the manual). It displays EC in the microSiemens scale - confusing, you will have to divide by 1000 to get this in EC...
As for pH, I used to use what Bruce said - an inexpensive liquid and chart, which is perfectly adequate and will do what you want it to.
I am now using a digital pH meter. These are much more fiddly if you are starting out, they need calibrating and the tip must be stored in a special buffered solution to stop it drying out. Once they are all setup though, it does makes reading pH a breeze. 
Wed, 2009/01/28 - 2:59pm
#4
Wow Peat, I didn't know you'd gone digital, I remember you talking about it. Which one do you have and how much trouble and expense, if you don't mind?
Wed, 2009/01/28 - 4:29pm
#5
It's a Hanna model, waterproof (much safer in case I drop it in the water!) and temperature compensated. For the 'ultimate' calibration you need two pH buffers, 7.01 and 4.01 It will work perfectly well on only the one buffer calibration though - pH 7.01
Buffers are generally available in pH 7 & 4, this one, for some reason, uses 7.01 & 4.01
The calibration procedure is simple with this model, just put it in the relevant buffers and it sets itself up - no manual adjustment required. Calibration is only once per month, I find it much simpler, quicker and less messy to use than the liquid & chart. I held of buying one for now as they won't last forever, at some stage the tip will need to be replaced and it's essential that it's stored correctly - if the probe dries out then you could cause damage, treat it well and it will last though.
Always buy one with a replaceable electrode, stay away from the cheaper ones without this - if they go then all you can do is put them in the bin!
Wed, 2009/01/28 - 6:40pm
#6
Nice one, Peat. I like the self calibration and accuracy. How do you store it? I may just have to make a run to the big hydro store and see what they've got. I haven't had a new gadget all week, my $6 kit is past half gone in only six months.
Wed, 2009/01/28 - 7:03pm
#7
Hi All,
Thanks for the comments. I've been back and forth. I think for my purpose, a separate EC meter makes sense. pH strips are fine for the readings we need. No sense getting too complicated from the get go! Heck - I just want to grow cucumbers!!
Thanks again-
Beth
Thu, 2009/01/29 - 11:35am
#8
Bruce - this one has a compartment in the lid with a piece of sponge. You soak the sponge in the buffer, usually 4, and simply place the instrument back in it's protective cap, the sponge keeps the tip wet.
Beth - you have come to the right place to grow cukes. 
Thu, 2009/01/29 - 5:24pm
#9
This is for sure the best place to grow cukes, Beth. I'm sure you've read Peat's glog, he's doing great just using an AG Classic. If it continues to take over his house maybe he could train some tendrils to be cup holders or train a big loop, top it with plexiglass and have a new coffee table. 
Peat, I hit the poor li'l hydro store down the street and they had one PH meter - only one, poor guys. They sold me this one for $40 plus another $10 for 8oz bottles of 4.0 and 7.0 cal. solution. I dip it in the solution and stir then try to read the tiny LCD readout (no memory so I have to do some contortions). When I'm done I have to rinse it in distllled water and blot everything with a tissue, The little glass electrode is way over on one side and it's hard to get a tissue around it. There's a sponge in the electrode cover that is kept slightly damp with distilled water. There's no auto-off so I have to remember to turn it off. All in all it's not bad for $40 but yours is head and shoulders better.
I used the tube and drops kit to test the 7.0 solution and it reads ~6.6. Distilled water read 6.8 while the meter showed 7.2. Quite a difference.
Fri, 2009/01/30 - 11:15am
#10
Interesting how your manual says to use distilled water to store your tip. My manual, in large bold letters, says do not use distilled water to store the probe tip - always use the storage solution or pH 4.
When I have finished with mine, all I do is rinse under normal water and shake the excess off. Place the unit back in it's cap (with sponge) and that's it - no wiping round with a tissue. The glass electrode should never be allowed to dry out, by blotting with paper isn't this going to dry it out? As well as possibly damage it? Oh well, that's what you manual says (bedtime reading for me , need to get out more!), so it must be right...
I'm going to give mine a couple of weeks before I check the cal again, see how stable it is.
Fri, 2009/01/30 - 5:18pm
#11
I read the manual on yours a few days ago and was also surprised by the difference. I don't know if I have a bad unit or it's just lousy but I'm going to return it, the readings are all over, it showed distilled water at 8.8 then 7.2 then 8.8 again within a few hours. I found a nice price on your Hanna here so ordered one with sachets of 4.01 & 7.01cal solutions. If I read correctly I can store it with 7.0 PH solution in the sponge, correct? I have two different ways to measure PH and now don't trust either. Hate it when that happens.
Sat, 2009/01/31 - 4:43am
#12
You can store it with pH 7.01 but the Hanna customer service chap told me it was better to store it with 4.01.
They do a storage solution, which I ordered but was out of stock. I e-mailed them asking if it was OK to store at 7.01 and they said use 4.01 I bought the bottles of pH buffers, I felt that they would be cheaper in the long run and I could dictate how much I wanted to use.
Wed, 2009/02/18 - 3:24am
#13
How are you getting along with your Hanna Meter, Peat? I had to recalibrate mine after only ten days or so, the readings went 0.5 high.Glad you mentioned using the 4.01 buffer for storage, one place I shopped said to use 7.01 but I went with the 4.01 on your advice. Found a MSDS sheet for the storage solution and it has a PH of 3.5. Hope I don't have to recal every two weeks but it's easy enough. Otherwise, this is a fine piece of equipment, I use it right alongside the Bluelab almost every day and they both take about the same amount of time to get an accurate reading. Thanks for the info!
Oh, do you have any clue what the "cloth junction" in the sensor is and how to pull it out 1/8" every now and then? I can't find any info about it other than the replacement probes mentioning it.
Wed, 2009/02/18 - 4:26am
#14
The cloth junction is a piece of fibre/cloth that interfaces the electrode to the meter. The 'cloth' can sometimes become dirty, moving it around can rejuvenate an electrode - don't ask me how, I assume it remakes the electrical connection by being moved.
The instructions I received with mine don't mention the junction at all, and there are no bespoke replaceable parts for it. I assume that if you were to order a replacement electrode then the cloth would be packaged with this? I'm not going to open mine until I have problems, the old adage ' if it works, leave well alone!'.
I have not checked my calibration for two weeks, just done one now and it's 7.05 @ 22.5 deg C
I think I can live with that little rise. 
Sun, 2009/02/22 - 2:15pm
#15
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).
Sun, 2009/02/22 - 6:32pm
#16
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... 
Mon, 2009/02/23 - 12:28pm
#17
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..?
Mon, 2009/02/23 - 4:27pm
#18
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.
Mon, 2009/02/23 - 5:15pm
#19
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.
Fri, 2009/03/27 - 9:32am
#20
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?
Sat, 2009/03/28 - 6:10pm
#21
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.
Sat, 2009/03/28 - 7:30pm
#22
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.
Sun, 2009/03/29 - 1:19am
#23
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.
Sun, 2009/03/29 - 9:16am
#24
That's good to know. I'm not exactly known for my patience.
I don't have a meter, but I pH is as important as EC. And measuring it with test strips costs money, you need to find the test strips, not very accurate / hard to employ, etc. (I do have test strips.)
Edit: I dunno if you want to check eBay as well. Amazon is safer, but...