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Ok, so after using about 70, 45 liter bags of LECA (Lightweight Expanded Clay Aggregate) made by a few different companies, I've finally ran into bad batch.

Since early spring of this year, we've used about 30 bags of Plant it! brand LECA with no issues. Until I noticed a dive-bombing pH problem in one of our little hydro systems which could not be explained. At least not by anything logical while running the system under normal circumstances.

The media was the first suspect. So, I took some media (new as well as out of that system) and placed it in a bucket of clean R/O water that had a pH of 7.3 and an initial EC reading of 166 micro Seimens.

Over the course of one week, the EC ended up at 1428 and the pH was at 3.5

Day 1 EC 166   pH 7.3 (Baseline)

Day 2 EC 550   pH 4.8

Day 3 EC 975    pH 4.1

Day 4 EC 1150   pH 3.9

Day 5 EC 1219   pH 3.8

Day 6 EC 1283   pH 3.7

Day 7 EC 1330   pH 3.6

Day 8 EC 1428   pH 3.5 It may be safe to presume that (likely) sulfur (or some kind of sulfurous compound) within the clay is the culprit.

Just figured I'd put this out there...Has anyone else had similar issues?

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[low whistle]

Yes I have experience with this.  I have two 4X4 beds filled with PlantIt that I bought back in March.  PH has dropped and been a problem for me since the very beginning.  Since this is my first system it took me a long time to figure out what was going on.  The PH just kept dropping long before I could ever get readings that the nitrification process was happening so it took me 3 months to get cycled.  Do you think it will ever taper off?  I really don't feel like spending hundreds $400 to replace this bunk PlantIt.

Hmm...Unfortunately, I would just be guessing in regards to the tapering off question Steve. When the acidic substance withing the clay has finally all been neutralized by a base...it will taper off (obviously). How long that will take (or if we'll still be alive by the time it happens) is anyone's guess. I've been adding KOH every other day to try to keep pH from falling so darn much with no luck, or signs of any tapering off whatsoever...so I'm not holding my breath.

I'm sorry to hear about your woes...it might be possible to boil the sulfur out of the media...IDK as I've not tried it. But it might be worth a shot...



Steve Erickson said:

Yes I have experience with this.  I have two 4X4 beds filled with PlantIt that I bought back in March.  PH has dropped and been a problem for me since the very beginning.  Since this is my first system it took me a long time to figure out what was going on.  The PH just kept dropping long before I could ever get readings that the nitrification process was happening so it took me 3 months to get cycled.  Do you think it will ever taper off?  I really don't feel like spending hundreds $400 to replace this bunk PlantIt.

It's possible that HydroFarm has been changing manufacturers/processes for the PlantIt grow media.  The PlantIt clay pebbles that I purchased a couple of weeks ago wouldn't sink even after several weeks of being submerged.

HydroFarm did solve the problem immediately by replacing the PlantIt pebbles with Hydro Corn.  Perhaps they would be willing to extend the same courtesy to you if you also got a bad batch.

Plantit PH dropper here too... after about 4-5 months of lots of Calcium Hydroxide, Potassium Bicarbonate, Egg Shells , Shell Grit and lots of dead fish my PH has stabilized at about 6.6.  I have heard somewhere there is residual sulfur that causes this.

PlantIt should market it as "acidifying media". Honestly, that sounds like just what the doctor ordered for those of us with hard water sources like I have. If it is natural sulfur in the clay, then it still qualifies as organic for certification. Vlad, have you tried hanging a bag of CaCO3 in the system to see if they cancel each other out?

I'm assuming you are bummed that the media loses an element of control in your system, but some oyster grit may be all you need to get control back, and liberate some organic calcium, eh?

Just to put this out there...if any of you purchased the Plant!t through us let me know and we'll take care of it for you.  We've had a few customers show up with this last winter, and while Hydrofarm is being pretty close to the vest about what happened our guess is what Vlad is saying.  They took it off the market for a few months and it just started selling again, and we think it was to solve that problem.  

Carson, is the water level in your bed rising above the top of the media?

Hi Sylvia,

There were about 12in of pebbles in the grow bed, and they would all start to shift and rise after the water level exceeded 7 inches during a flood.  We never did get to the bottom of the mystery, but HydroFarm was very helpful in finding a solution.

That's great to hear, Carson.  What did they suggest you do?  I have another customer who called last week about the same issue, which I've never seen before as long as the water isn't going over the top of the media.

I'd imagine that we both received rocks from the same bad batch - perhaps something was overlooked in quality control.  HydroFarm replaced the faulty PlantIt media with Hydro Corn as soon as they heard of the issue.

I had the exact same problem. But I did not really see it as a problem, It just meant that I added a bunch of calcium and potassium to get it back into the low 6, and my plants (love it) and fish seem just fine. I got a strong buffer going from the start that way.

I think there is a lesson to be learned here. We should check every new batch of media, regardless of what it is, before putting it in a system. The test Vlad did should suffice. Seems simple enough and only takes a few days. 

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