New member - seedlings with rockwool, help w/ meter?

[Indyca5000]

Hello 420magazine. I've been poking around the site and I'm finally getting going on my new project.

Soaking my rockwool plugs in PH 5.2~5.5 water with no nutrients added, comes out of the tap at about 40ppm... figure its safe to use for seedlings... plan on soaking the rockwool overnight tonight then putting seedlings in when they're ready.

They'll be sprouting in a cardboard box with a single 23w CFL. Running the light all day and the temp hasn't risen over 28C~82F in the middle of the box.

There are 2 feminized seeds germinating and one has already split revealing a healthy white taproot! The rockwool won't be ready for some hours though so hope she saves some energy.


Meter isn't working for TDS anymore... it has been in storage for some time... It was stored with wet foam on the probe and it was still wet and the PH seems consistently working but TDS isnt? might try giving it a good rinse? anyone know a trick like rubbing alcohol or something?

Its a Milwaukee SM802 calibrated with general hydroponics 1500 ppm and 7.01 PH solutions. PH seems to work great, but TDS is totally wack.

 

[PrairiePoet]

You could try soaking the TDS probe in a cleaning solution for a few days and see if that fixes it.

 

[Indyca5000]

Alright, will inspect the tip. Read that bleach /alcohol are ok for cleaning out organic junk... EC on the probe might just be fubar though because it was stored wet.
Apparently the probe is supposed to be stored dry, which is contrary to what it said on the little information sheet it came boxed with.



edit: soaked the tip in rubbing alcohol, ran under faucet. used microfiber electronics cleaning cloth to wipe out some of the brown gunk that was indeed at the base of the probes. Don't think I could get enough of the gunk out I think the TDS function is fubared because its supposed to be stored dry and not wet. the vendor said store wet so you don't have to recalibrate PH but they're wrong.

 

[PrairiePoet]

Alright, will inspect the tip. Read that bleach /alcohol are ok for cleaning out organic junk... EC on the probe might just be fubar though because it was stored wet.
Apparently the probe is supposed to be stored dry, which is contrary to what it said on the little information sheet it came boxed with.



edit: soaked the tip in rubbing alcohol, ran under faucet. used microfiber electronics cleaning cloth to wipe out some of the brown gunk that was indeed at the base of the probes. Don't think I could get enough of the gunk out I think the TDS function is fubared because its supposed to be stored dry and not wet. the vendor said store wet so you don't have to recalibrate PH but they're wrong.

pH probes are to be stored wet in a storage solution. EC probes are just two conductors that measure the amount of electrical current between the two. So most likely you are fubar'd.

 

[Indyca5000]

pH probes are to be stored wet in a storage solution. EC probes are just two conductors that measure the amount of electrical current between the two. So most likely you are fubar'd.

Yeah. storing the probe wet let some bacteria grow or something not sure what really went on with it but can't get all the gunk out... is it right to say that the pH meter is stored wet so you dont have to recalibrate, and drying a pH meter out for store just means you have to recalibrate it before next use?

 

[PrairiePoet]

Yeah. storing the probe wet let some bacteria grow or something not sure what really went on with it but can't get all the gunk out... is it right to say that the pH meter is stored wet so you dont have to recalibrate, and drying a pH meter out for store just means you have to recalibrate it before next use?

Well, no. Ph probes have a porous ceramic in them. If this dries out completely then it can't soak up water again. Look for a PDF from Hanna about storing pH probes.

 

[Indyca5000]

K thanks a lot