Drain and Fill Question [RESOLVED]

I have a question how the Drain / fill works with Grobo

So if I drain my Grobo then fill with R/O water let Grobo dispense its nutes then I drain that water into a bucket. Then I fill the same water back into the Grobo since my Ec is high will Grobo just adjust Ph or dispense nutes again?

I know the question doesn’t make sense why are you going fill the same water again but my gears are working on a idea but kind of need this question answered first

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I remember support saying if your EC is above a certain point after a fill, Grobo will not dispense nutes…I believe 500. @Stephen?

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I was under the same general impression but I figured I’d ask the question instead of running the test and wasting nutes

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:popcorn: man I’m just here wondering what it is u starting to :shallow_pan_of_food: brew up :joy::dash::seedling:

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Me too!!!

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Very interesting! Inquiring minds want to know!

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We will see if someone from Grobo replies after the Holiday if not I will just have to do the experiment when I have some time

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From the question, i’m guessing you’re just tryingg to up your EC withh only ggrobo nutes? Kinda like me playing with water sensor connections keeping my fill at the hhiggh level with my hydroton grow. Soorry for theh bad typing but my bluetoothh keyboard sucks lol.

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Hey @Mpower11,

Your unit will dispense nutes each time it identifies a successful drain/fill cycle. So, if you are using the same water again, you will receive a double dose of nutes.

The unit will check your EC to determine if you are using tap water or RO/distilled and adjust the nutes depending on the results of this check, so it won’t be the exact same dose if you refill.

Sooooo, YES! You can use the Grobo to feed a tent grow if you don’t want to bother mixing nutes. (I’m guessing here, but…) The catch is that the pH adjusts slowly (hourly) in the unit, so you may need a full day to get into perfect pH range before draining and using that water somehow.

Hope that helps!

Cheers,
Stephen

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@Stephen Thanks for the reply… I thought it worked different :thinking:

Example

Since it will double dose nutes say your Ec is 1.9 it will dose to about 3.8 sadly this kills my experiment I had in mind. Back to the drawing board…

I was hoping if it read high Ec it would just adjust Ph… It’s to bad this wasn’t a advanced function for users mind you this could case more problem than it’s worth for Team Grobo and most users.

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  • ([RESOLVED]):

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@Stephen still spinning gears on this.

What happens in this case

  1. drain Grobo
  2. fill Grobo R/O water
  3. let nutes dispense
  4. drain 3 litres of water out (stop it manual)
  5. fill back with R/0 3 litres

I’m thinking at this point Grobo will just adjust Ph now.

Can anyone confirm

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I believe in that scenario since it did not fully complete the Drain, the system will not dispense nutes once you Fill. It treats it like a top-up of water.

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I was thinking the same thing just wasn’t sure what the system thinks when you don’t complete the drain cycle

Keep in mind that if you manually stop the Drain process the app seems to get stuck in wanting to continue the Drain until it completes. So you may need to power cycle the Grobo and relaunch the app. This should allow you to advance to the Fill process.

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Thanks for the tip

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Hey @Mpower11 & @miami5th,

Ya’ll got it! If the bottom water level sensor doesn’t drop, the system will register as a top up and simply maintain the pH level hourly.

You will need to power cycle to exit the drain early too. Great catch @miami5th!

Cheers,
Stephen

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Thanks for the reply’s

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