Maintaining GROBO after harvest/ prep for second grow [RESOLVED]

hey guys,

part 1:

so I harvested my plant and I cleaned the GROBO a bit and removed the water from the water reservoir and began the drying mode. I did put the ph meter in water solution so it don’t dry out, but I didn’t do this for the EC meter.

I am now done with drying my bud but I am not sure if the EC meter is working anymore given that it was left dry for about a week.

do i need a new EC meter???

part 2:

so I have ordered some seeds but they’ll arrive next week, what do i do with the GROBO in the mean time after cleaning and sanitising it? can i just switch it off and then turn it back on when i receive the seeds?
ALSO can i use the ph/nutrient bottles from my previous grow??

any extra tips would be appreciated xxxx

thanks xxxx


likely youll need a new EC meter. if the drying mode is done you can power off your machine if you want. Most of us usually have another going almost immediately as time becomes your non friend.
yes keep reusing up all your nutrients.


what is the name/type of the EC meter ?

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I doubt it unless you notice visible signs of rust on the plates at the bottom/tip of it.

The pH probe is the one with a more limited lifetime. It contains fluid that degrades (or leaks/gets polluted) over time.


Hey @Zahraa_Msa,

Great questions. Yes, the EC probe can stay dry, you should be good to go there. Keep the pH probe in tap water, not RO or distilled and you will be fine there too. You can unplug the unit and when you are ready to go again, simply plug it back in and select a new recipe. Then fill it up when the prompts appear.

Nutes last 3 years, so you can use any left overs for sure!




Just curious, why tap water?

Was wondering the same thing.

Because its cheap and only meant for temporary fix.

Great advice and support here everyone!

To add @Zahraa_Msa - The EC and pH meters are made by Bluelab. It would be a good idea to have the Bluelab Care kit which helps you maintain, clean, calibrate, and store your probes.

Check it out here:


oh yes i have that :slight_smile: but I only cleaned/calibrated the sensors after harvest, but on the pack it was recomended to clean the sensors at least once a month, should i do that or is waiting till harvest okay?

I think we should perform the cleaning/calibration health check every 3 months


Probably because since the water is deionized it could leach the probe’s ions into the water which could damage the sensor readings

thanks! I will do so for my current growth!

Hey @jamestournas,

Great question! Traditionally you would store your pH probe in a storage solution (KCI or potassium chloride/water mix). If you don’t have any on hand, you can use tap water as a substitute.

Why not use RO or Distilled?
Your probe won’t like it! It will reduce the lifespan of your probe and you may lose your reference value faster (calibration). Think of it a bit like these two examples.

  1. RO or distilled water are empty of salts and have 0 EC. Think of this as no atmospheric pressure. Tap water does have salts (Potassium, nitrogen, phosphorus, calcium, etc). Think of this as the pressure you would feel in the deep end of a swimming pool. That pressure is great at reducing the amount of liquid the pH probe needs to dispense to get a reading. With no pressure, the liquid will leak out much quicker, reducing the life of your probe.

  2. RO or distilled water are empty of salts, and have a very empty room feel. When you shout into an empty room, there is a bunch of echo and bounce back. Using tap water is better, because the EC will not be 0 (there will be furniture and carpet and paintings etc in the room). This vastly reduces the echo. This is what we want when storing our probes to maintain the calibration.

Hope that helps!


PS - Yes the flush stage isn’t great for your probe, and the system has a bit more effort to expend keeping that pH level perfect without any EC present. 4-6 flush stages a year = replacing the probe every 12 months on average.