Anyone using Growstones?

[Roger & April Frederick]

I'm hoping to find someone who is actually using the Growstones recycled glass media.  I'm very interested in it since it is a much more sustainably produced material.  However, a quick read of their website indicates that it may increase pH. Is anyone using it and what has been your experience?

[Roger & April Frederick]

That's the part I was concerned about, the fact that they added something to counteract the pH. Even though I don't have fish in the system yet, I'm really trying not to add chemicals to adjust balances.

It was about the same price (~.02 to .04 per liter cheaper) as the Hydroton at most of the suppliers I checked. You have to do a little converting to see it though since the Growstone is sold in liter bags and the Hydroton in cubic feet.  The thing I like best about it is that its a recycled rather than a mined product.

 

[Roger & April Frederick]

I've seen the Growit at my local store and thinking about trying it. I really like the idea of the recycled glass since it doesn't require strip mining to acquire and is produced here in the US, but after I pay the shipping I'm not sure it makes the most economic sense right now.   I don't see why the tumbled glass wouldn't work in a media bed just as well as rocks but I wonder if it would be too heavy for raft pots.  

Randall Wimbish said:

There is a cheaper product like Hydroton called Growit clay pebbles. I just put some in a small growbed. I have often wondered about tumbled broken glass as a media?

[Dave & Yvonne Story]

I started using grow stones about a year ago.

I liked the published test results.

I did not notice any pH difference from my hydroton tanks.

I did notice that the time involved in cleaning the shards was significant compared to hydroton.

the grow stones did disolve back into shards. As the grow stones disolve, I replace them with hydroton..

I will try Growit clay pebbles.

[Roger & April Frederick]

Thanks, Dave.  Interesting to know that the grow stoned dissolved...odd.  I decided to go with the Growit pebbles myself as I found them at a very good price at a local hydroponics shop.  They were rather tedious to get cleaned up, though.

Dave Story said:

I started using grow stones about a year ago.

I liked the published test results.

I did not notice any pH difference from my hydroton tanks.

I did notice that the time involved in cleaning the shards was significant compared to hydroton.

the grow stones did disolve back into shards. As the grow stones disolve, I replace them with hydroton..

I will try Growit clay pebbles.

[Dave & Yvonne Story]

I did start to look for growit, I am about to setup another grow-bed.

thank you for the info

dave

[TCLynx]

I have a sample of Growstone to test but I haven't had time to setup my media trials yet.

[Dave & Yvonne Story]

I bought 10 bags.. then I ordered a pallet, 3 mos later I was sorry

in the bag they look good. I cannot even think of a way to test a small amount.

[Dave & Yvonne Story]

I found it on amazon.

I am going to try locally, tomorrow.

[Rob Torcellini]

I bought a bag of them to evaluate.  They are extremely lightweight, but were very abrasive on the hands.  There are a lot of shards in it too.  I was very concerned about a shard getting into the fish tank and having them ingest it.  At least with the shale, they are smooth.  Even a broken piece of shale isn't as sharp as the grow stones.  They may be fine but I didn't put them into my system.

[Dave & Yvonne Story]

LOL

I forgot about

during the cleaning phase, my hands were raw from the shards

[Roger & April Frederick]

My bad too, just carried the mistake forward.  Plantit is is what I have, too.  Thanks Randall for catching our Ooops.

My bad Dave and all. Try looking for Plantit clay pebbles. Not Growit.

[Paula Costa]

Hello there!

Thought I would jump in and talk to all the great Aquapons out there wondering about:

1. safeness of using Growstones super light weight, highly porous recycled glass substrates as a growing medium / biofilter for growing fish and veggies,

2. if the product dissolves in water through time.

3. Growstones R&D efforts towards Aquaponics and/or Aquaculture.

Due to Growstones sand-paper like surface texture, it is understandable that some people may wonder if its surface can damage roots, worms or fish.

Growstones manufacturing process creates round pores inside each aggregate or pebble. This creates a very large surface area, with many smooth-surface pores, ideal for attachment and growth of nitrification bacteria. 

Growstones are pretty much ready to use out of the bag. And no specially long soaking time is necessary. It is a good practice, as in other media to rinse it, and place in the system, let the system run for a while to check pH, water levels, make sure all is well. Slowly adjust for pH as necessary before introducing fish or plants, as would be the case for other growing media. And you should be ready to grow.

But let me talk about how Growstones are actually made from start to finish and the R&D conducted with growing fish with Growstones:

1. Yes. Growstones are made from glass. However, glass pieces/chard or any intact glass is something you will never find inside a Growstone plant. Glass lives in the landfill, where is is crushed by the city. Then it is grind into a super fine powder- like flour. This flour is then mixed with baking soda (natural foaming agent), and a also natural pH buffer, which is calcium phosphate. These are added in very small amounts to the mix, which is 98% powder glass.

The mix goes into a kiln where all components are melted together. The process is a simple baking process - the glass melts into a viscous mass like honey, while at the same time the CO2 gas gets released from the calcium carbonate and tries to escape bubbling up through the honey-like glass mass. as in bread, the bubbling of the CO2 is what makes the bread-like texture inside and raises the bread. Instead of wheat we use glass flour - no difference.

If any fines are present at the bottom of the growing bed, these would be due to shipping and handling. These fines are nothing but silica grains quite similar or smaller to grains of sand you see in the shallows in the sea where small fish often times can be found going by their own lives. And as you know, these grains pose no danger to fish gills. 

2. Typically Growstones do not dissolve in water and keep their physical integrity through time. Sharing from my personal experience as a Growstone grower - I grow with Growstones in DWC and Ebb-flow systems and my reservoir tanks are very clean at all times.

3. For the more curious Aquapons looking for alternatives but who really want to know what these alternatives really are (as I would) - I invite you all to check the link below.

http://www.growstone.com/products/green-roof/aquaculture/

The link takes you to a YouTube video showing our fish grown in one of Growstone multiple long term controlled trials at The University of Arizona, in Tucson. We compared the performance of Growstones, bioballs and biobeads, in Aquaculture systems to raise tilapia. It also shows Dr. Fitzsimmons, who was responsible for the trials talking about the fish. 
This link also includes a summary of the results from these trials relative to water quality parameters and fish growth rates. All water quality parameters are good and fish rates in Growstones were slightly superior compared to the other two media tested. 

I encourage anyone to ask me any questions. I welcome the opportunity to answer questions. I would also like to learn more details from growers who have experienced any issues with Growstones. I am here to help. 

Thank you!

Paula Costa 
R&D Director, Growstone