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Help - Post Growstone pH Problems


New Member
Hey everyone. It's been like, 5 years since I've been on here. Great community... I'm back with a urgent request for help.

Here's the situation. I started with a 15" mother plant in Rockwool, plan was to transplant to Hydroton in GH Drip bucket - but the shop was all out but the guy working there suggested I use Growstones as a medium instead. After reading their website with claims that it's far better than Hydroton and sustainable and USA Made I said sign me up.

Package said do a 'quick rinse' before use. I did a more thorough cleaning like I would do for Hydroton anyways.

For the rest of the day after transplant, I found the Res shooting up to nearly 8 ph no matter how much acid I threw in. After like 20 min. it would be right on it's way back up... After reading online I realized others have this issue too, and that extreme washing for multiple days can help avoid this.

Anyway - I was done dealing with this awful medium. So I pulled her back out, rinsed out the bucket, and put Hydroton and the plant back in.

Now it's been a few days, and I'm STILL getting huge spikes in Ph... In the center combined with root is still the original chunky rockwool that is really part of the plant now. Why is my ph still shooting up??? Is it the rockwool that has gained the alkaline nature of the growstones?

I'm really confused and kind of desperate as I'm running out of tricks. Thought maybe one of you pros could help me out. If you read this far many thanks.


New Member
Re: Halp. Post Growstone PH problems :(

Okay - I'm trying to self-help here. So here's some ideas:

First verify that for sure the cause of the high PH is coming from the medium, not the reservoir. Going to swap for a different res and run for a few hours and see if the shift still happens. If so, I'll have a little more info. Will update after I try this.

If it is the medium, then it seems my options are a heavy flush of some kind... Not sure what options are available to me. Feels like removing rockwool isn't going to be possible.
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