Buying Used PH Meter? - Indoor Grows - Hydro - International Cannagraphic Magazine Forums

5cooby Doo · 12-11-2017, 03:09 PM

I found local guy selling Blue Lab Guardian for me for $125USD. He saying it's 2year old and he always keep it stored in water. (so that's good I know he stored it correct.)

Is there anything I should know for buying this one used..anything to check out specifically? Or it's good deal if it's working?

Mikell · 12-11-2017, 03:25 PM

Lowball 100.

If the EC meter reads correctly (I would bring solution) you can always grab a new pH probe. If it is close it likely just needs a cleaning as per instruction and that knobby paste.

Been using the same one for 4 years.

5cooby Doo · 12-11-2017, 06:52 PM

Thanks Mikell.

I don't have any solution to test it. What kind of solution? Like a PH 7 and PH4? Or just any nutes?

He wanted 155USD, I told him 125USD. Cheapest I could find it at the store is 310. So basically half price.
(I converted to USD prices because most of you guys are from U.S. I noticed.)

I was just worried about any problems it may have...he stored it correctly and he says its working.

Mikell · 12-11-2017, 07:24 PM

Ideally you can see it function. If he doesn't have the EC, pH 4 and 7 calibration solution, bit of a red flag. But really, unless he's a monkey and has broken the EC probe I would snap it up at 125USD.

The EC probe isn't calibrateable per say, you clean the probe until it reads the same as the solution.

Most deviations on the pH reading can be corrected with 24hrs in KCL storage solution.

The only Bluelab care products I buy are the KCL and the EC probe cleaner. The calibration solutions is half the price for other brands.

Stoned rambling.

5cooby Doo · 12-11-2017, 07:30 PM

AHH! I was going through manual for Guardian.. it says only part that EVER needs to be replaced is the PH Probe.

..so as long as everything else is good, It should be fine. Maybe I'll try to bring down price more.... as I was reading it should NOT be stored in distilled or RO water... only in the ph7 solution. So I have to make sure what guy was using to store in.

meadowman · 12-11-2017, 07:37 PM

it's ok to store in tap water i've been told….that's what i have used for 2 years now anyway.

Mikell · 12-11-2017, 08:01 PM

I leave the probes in the reservoir or a cup of nutrient solution. Our tap is usually 20ppm.

It was my understanding the probe will deviate towards any solution if left long enough (or lose ions to distilled/RO) and to periodically correct with KCL. I have yet to see this and just clean/calibrate every 2-3 weeks and store in KCL for 24hrs every other month.

5cooby Doo · 12-11-2017, 09:33 PM

Mikell you ninja'd me on your second last post, did not see it after posting mine lol.

He said he should have some solution left so he'll test it tonight and let me know. Hopefully it works.
I don't want to lowball, he was reasonable with the negotiating, and there's not many used ones around locally.

Meadowman, well if yours is still good it should be fine. He said to me also, as long as it's kept wet it's fine. But said he will test. He had it in a water bottle -water.
...... if you're running it for a grow, at least 3 months it's in water.... so I mean can't be to bad stored in regular water right. (worst case I need a new PH probe, still not a bad deal compared to brand new price.)

The manual said use EC probe cleaner Or dish detergent (With a soft toothbrush or your finger), so you might just save a couple more bucks there, Mickell. You sure take very good care of your unit sir! Kudos to that!

You're also right I believe, where it will deviate to what it is left in.. think I read that in there to somewhere.

gaiusmarius · 12-11-2017, 10:06 PM

you just need it to read correctly for at least the ph 7 calibrating liquid, ideally test it in both the ph 4 and ph 7 liquid. you can buy a small sachet with 25 mils of each, just enough to test that it's working. although buy a small bottle of each will be best to keep it calibrated in future.

5lrootsexcel · 12-11-2017, 11:39 PM

A new ph probe is around $45 so even if the one included is busted, you get a working unit for under $200.

You're not supposed to store the ph probe in water. That includes tap. Store it in the storage solution because water will cause the salts to basically elute out and your ph readings will no longer be accurate.

12-11-2017, 03:09 PM	#1
5cooby Doo Member Join Date: Dec 2014 Posts: 52	Buying Used PH Meter? I found local guy selling Blue Lab Guardian for me for $125USD. He saying it's 2year old and he always keep it stored in water. (so that's good I know he stored it correct.) Is there anything I should know for buying this one used..anything to check out specifically? Or it's good deal if it's working?
	Quote

12-11-2017, 03:25 PM	#2
Mikell Dipshit Know-Nothing Join Date: Aug 2013 Location: Van Isle, BC Posts: 4,971	Lowball 100. If the EC meter reads correctly (I would bring solution) you can always grab a new pH probe. If it is close it likely just needs a cleaning as per instruction and that knobby paste. Been using the same one for 4 years.
	Quote 1 members found this post helpful.

12-11-2017, 06:52 PM	#3
5cooby Doo Member Join Date: Dec 2014 Posts: 52	Thanks Mikell. I don't have any solution to test it. What kind of solution? Like a PH 7 and PH4? Or just any nutes? He wanted 155USD, I told him 125USD. Cheapest I could find it at the store is 310. So basically half price. (I converted to USD prices because most of you guys are from U.S. I noticed.) I was just worried about any problems it may have...he stored it correctly and he says its working.
	Quote

12-11-2017, 07:24 PM	#4
Mikell Dipshit Know-Nothing Join Date: Aug 2013 Location: Van Isle, BC Posts: 4,971	Ideally you can see it function. If he doesn't have the EC, pH 4 and 7 calibration solution, bit of a red flag. But really, unless he's a monkey and has broken the EC probe I would snap it up at 125USD. The EC probe isn't calibrateable per say, you clean the probe until it reads the same as the solution. Most deviations on the pH reading can be corrected with 24hrs in KCL storage solution. The only Bluelab care products I buy are the KCL and the EC probe cleaner. The calibration solutions is half the price for other brands. Stoned rambling.
	Quote 1 members found this post helpful.

12-11-2017, 07:30 PM	#5
5cooby Doo Member Join Date: Dec 2014 Posts: 52	AHH! I was going through manual for Guardian.. it says only part that EVER needs to be replaced is the PH Probe. ..so as long as everything else is good, It should be fine. Maybe I'll try to bring down price more.... as I was reading it should NOT be stored in distilled or RO water... only in the ph7 solution. So I have to make sure what guy was using to store in.
	Quote 1 members found this post helpful.

12-11-2017, 07:37 PM	#6
meadowman Member Join Date: Nov 2012 Posts: 608	it's ok to store in tap water i've been told….that's what i have used for 2 years now anyway.
	Quote

12-11-2017, 08:01 PM	#7
Mikell Dipshit Know-Nothing Join Date: Aug 2013 Location: Van Isle, BC Posts: 4,971	I leave the probes in the reservoir or a cup of nutrient solution. Our tap is usually 20ppm. It was my understanding the probe will deviate towards any solution if left long enough (or lose ions to distilled/RO) and to periodically correct with KCL. I have yet to see this and just clean/calibrate every 2-3 weeks and store in KCL for 24hrs every other month.
	Quote

12-11-2017, 09:33 PM	#8
5cooby Doo Member Join Date: Dec 2014 Posts: 52	Mikell you ninja'd me on your second last post, did not see it after posting mine lol. He said he should have some solution left so he'll test it tonight and let me know. Hopefully it works. I don't want to lowball, he was reasonable with the negotiating, and there's not many used ones around locally. Meadowman, well if yours is still good it should be fine. He said to me also, as long as it's kept wet it's fine. But said he will test. He had it in a water bottle -water. ...... if you're running it for a grow, at least 3 months it's in water.... so I mean can't be to bad stored in regular water right. (worst case I need a new PH probe, still not a bad deal compared to brand new price.) The manual said use EC probe cleaner Or dish detergent (With a soft toothbrush or your finger), so you might just save a couple more bucks there, Mickell. You sure take very good care of your unit sir! Kudos to that! You're also right I believe, where it will deviate to what it is left in.. think I read that in there to somewhere.
	Quote 1 members found this post helpful.

12-11-2017, 10:06 PM	#9
gaiusmarius Senior Member Join Date: Feb 2005 Posts: 16,618	you just need it to read correctly for at least the ph 7 calibrating liquid, ideally test it in both the ph 4 and ph 7 liquid. you can buy a small sachet with 25 mils of each, just enough to test that it's working. although buy a small bottle of each will be best to keep it calibrated in future. __________________ Making BubbleHash with Bubbleator Searching for SourPoison, AfghanDieselHaze and CheeseHaze keeper making canna butter
	Quote

12-11-2017, 11:39 PM	#10
5lrootsexcel Newbie Join Date: Nov 2017 Posts: 11	A new ph probe is around $45 so even if the one included is busted, you get a working unit for under $200. You're not supposed to store the ph probe in water. That includes tap. Store it in the storage solution because water will cause the salts to basically elute out and your ph readings will no longer be accurate.
	Quote