Oh Oh not happy Jan -I think!

[ineke]

After giving Jayc advice that the local hydroponics stores carry PH buffers and storage solutions I thought it time I took my own advice and  visit my local store. I gathered up my cheap TDS pen, My mid range Hannah TDS pen and my cheap Chinese PH pen and off I went. The guy was very nice and very helpful but jumped in a bit quick. He checked the PH pen and said it just need a good clean with a new toothbrush and to continue to recalibrate as I had been doing. Not to worry about storing this one wet. OK safe so far. Next he took my Hannah pen and searched for a calibration screw -now I had been told by Hannah this was a factory calibrated pen that didn't need to be recalibrated -infact I hadn't even seen the calibration point which is on the side and apparantly set at an angle so a bit fiddly but my friendly guy fiddled until it turned a bit- getting a bit worried here- he then got some calibration liquid and did some more fiddling looking more and more confused as he fiddled. He put the Hannah down and played with the cheaper pen -again he fiddled and fiddled decided the batteries needed changing and proceeded to change said batteries -ok getting a bit more worried. Still fiddling with the cheap pen he decided it couldn't be calibrated -oh oh. went back to the Hannah tried it in tap water tried a few other things and then decided the  solution he was using may be a bit old as it was the last in the bottle. He opened a new bottle still no luck so he got out a brand new blue lab TD/EC truncheon and checked the fluid. A light seemed to go on in his head and he said oh Hannah needs a different calibrating solution and I should get on their web site to find out what it was. He looked down at both my now not very reliable TDS pens that he had fiddled with and changed settings on and decided perhaps he better do that so now I'm extremely worried - all I went there to do was get the right calibrating and storage solutions with pens that may not have been accurate but at least by me using them consistantly on my tanks the tanks were stable to those pens- well not any more they won't be!! So now I have left my Hannah and my other pen with him and he is going to get on the web and try to find out what they need to calibrate them. I'm to phone back tomorrow and find out how he went. I hope if he has wrecked my pens he gives me a decent discount on some new ones!!! I'm not sure where I stand -yes I took them there for help but I didn't ask or expect him to calibrate them -I know enough that different brands have there own calibrating TDS solutions - I didn't ask for new batteries but as he seemed to know what he was about - he is the shop owner and has been there for many years- I thought I was safe I didn't ask for them to be calibrated but he seemed to know what he was doing so I just stood and watched.I guess I have to learn to speak up in future. I will let you know the outcome tomorrow afternoon when I phone him to see what he has found out. Anyone know a good brand of TDS pens LOL not too hopeful here!!!!!

[jayc]

Oh no. 

TDS pens rarely need calibration, unlike pH pens. TDS pens don't need storage solutions either. TDS pens should be stored dry.

Before fiddling with the TDS pen, did he test the TDS pen in a known calibration solution? Was it not reading correctly?

 

32 minutes ago, ineke said:

Anyone know a good brand of TDS pens

I use HM digital AquaPro AP-1. I find it good and accurate.

Edited February 3, 2016 by jayc

[ineke]

Jayc he used a calibration fluid he had out but he had already turned the screw. I had not ever tried to calibrate the TDS pen. The cheap pen and the Hannah were 10 points apart on my tank  so I wasn't too worried as long as I just used 1 pen and kept my water to the properties of that pen the tanks should be fairly stable. I really only wanted to see if he could check how far out the pens were to his water and TDS.  I had received shrimp that were in water with a TDS of 200 when they were packed but my pen showed 280 when I unpacked them. I realise that 3 1/2 days in a bag in hot weather would raise the TDS  but I thought I would check out how far out my pen was just out of. Curiosity - well curiosity killed the cat in this case the TDS pen! I think when I get it back if he couldn't do anything with it I will try to change it back to what the tank was reading before I took the pen to him- luckily I checked it before I left. If I can get it to read the same then it should be close to what it was. My RO water isn't 0 at the moment so I can test it on that but I do have a fresh bottle of demineralised water that should be 0 I think. I've checked to see how much my Hannah pen would be to replace -$100 - so if I need a new one I might go for another brand like the HM . I just don't know if he would be liable for the damage if he can't fix it?

[Disciple]

Its hard to be angry when people go out of their way to help you but at the same time when its not something you asked for and something he was not sure about it  would be very frustrating.

Hopefully he will do the right thing by you.

[jayc]

@ineke don't stress too much. All is not lost.

The store person made some rookie mistakes, like using an opened bottle of calibration fluid to test. Which could be contaminated or expired. Calibration fluids have an expiry date.

All he needs to do is get hold of some new 1,413 µS/cm conductivity solution and recalibrate the TDS pen with this calibration fluid.

1,413 µS/cm conductivity solution should give you 342ppm TDS reading.

I don't see why he would need to get specific Hanna calibration solutions. I checked the website and Hanna sells calibration solution that is prepared against a Standards based formula. So any similar certified solution will be enough, since it is a known quantity that the TDS pen is measured against.

[ineke]

He opened a new bottle eventually and checked it with a new blue lab truncheon . Hopefully tomorrow he will have the same info as you got and can recalibrate my pen . If not I will give him your info thanks Jayc. Hopefully he hasn't fiddled too much that it can't be rectified. He did keep saying EC and I kept reminding him this was a TDS pen that already changed the EC to ppm. He also said my readings were way out for salt water and I had to keep saying no it's fresh water so maybe he was expecting a different reading - I'm only guessing I don't really know what the problem was. 

[jayc]

Any update?

[ineke]

Just got home and no fix unfortunately. My pen apparantly is an old model and needs a different calibration solution according to Hanna Australia printout. I can't get it on eBay so have sent a request to Hanna themselves but it looks like they deal with companies not private individuals. I will have to see if they get back to me . I need HI 70080 solution 800ppm @ 25c. They have it in sachets so just need to be patient for an answer. In the mean time I have my old pen which reads slightly different but close enough. I have re calibrated the Hanna to the tank reading it gave me yesterday before this all happened. We figured that if I got that reading back then even if it is wrong it is still stable with my tanks and as the shrimp are doing well it should be ok. If I can't source the correct solution I will have to buy a new pen as I don't have confidence in this one as it stands at the moment. 

The shop guy - apart from stuffing up my readings- was only trying to be helpful and I don't think I can force the issue in anyway so I just have to wear .