First grow with blue cookies!

Did a cleaning and calibration on my ph probe today. The health check said that it did need calibration, so after calibrated it, the health check failed and said it needed to calibrate again.
Calibrated again. Health check still failed…
Cleaned and calibrated yet again and the health check failed again.

I replied to my support ticket about this as I’m thinking that the ph probe is bad, which would explain the rusty spots with a 1 month old grobo. When my grobo arrived, the light wouldn’t work correctly and after some troubleshooting, I noticed that the exhaust fan’s plug was ripped off the circuit board and the whole circuit board had been jostled off the standoffs (no nuts on the standoffs either, just a bunch of hot snot aka hot glue.) So I’m guessing this unit had a rough transit.

I keep reading about the ph probe being particularly sensitive and now my guess is that it also got damaged during shipment.

Here’s how the plant is looking now.

She is developing more rusty spots on the tips of the leaves, so I’m thinking the adjustments made 3 days ago are not making much of an impact. Oh, the unit is still going through a lot of bottle 2 acidic, about 3/4" of the bottle, which seems like way too much to me.

On the left is from 2 days ago and the right is just a few moments ago. She still looks like she is burning, especially the first set of leaves underneath.

What do y’all think? Bad probe? How do I keep her healthy until I get a replacement probe?


The only way to keep her going if it is a bum probe is to ph the water yourself, you’d have to unplug 1-2 and manually do it. I’d check it every so often as well to watch for fluctuations. Probably your only option really unless someone else can think of something :man_shrugging:
Did you send in a ticket explaining all this? They’ll help you more thoroughly I’m sure


I’d come to the same conclusion, the probe or connection is probably bad. That might also explain why it’s using so much of the first bottle. I go through more of the 2nd than the 1st and from what I’ve seen that’s normal – to use up most of the 1st bottle so quickly is abnormal.


Meant to add this to that response: in the rear through the litte trap door you can access the board the connector for the probe is on. It’s a BNC-style connector (twist-locking). That could be the problem if it hasn’t been ruled out, confirm the wire is seated in the connector properly (unplug/replug it).

See here for more info on that:

Edit: I’m also curious now – can those two wires be connected backwards (wrong probe in wrong port)?


Ok good to know. I’ll give that a check in the morning. I suppose the connections could be on the wrong connector, since the hardware is the same. Not sure what the software thinks about it, if the signals are similar.

In the meantime, I’m wanting to check and adjust the ph manually. I don’t have a ph meter (yet) but will the pool ph strips work enough to get by?

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It should give you a general idea yeah but you want to be within a couple decimal points realistically.

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You might have better luck with the liquid over the strips, if you can find something like this:

When choosing a product like the strips or liquid for testing, try to prefer one that is labelled for “hydroponic” use over one for pools or general use. Those other ones will work if there’s nothing else, but you will get a greater resolution with the hydro drops as they make it easier to tell between 6.0 vs 6.1 etc.