Aquaponic Gardening

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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?

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I put worms in my grow-beds and my canisters.

I tried the expanded shale, but the weight and cost was not less than Plant!t.

Seems expanded shale's high cost is in the shipping.

I have a sample of Growstone in front of me. Looking at it and knowing a lot about pumps, I would say the very fine granular sand (or glass) in the bottom of the sample bag is inevitably going to be a problem for pumps. My intention is to use the product as a grow media in a seed tray. Once the seedlings are large enough I will pull them from the tray, wash off the growstone and plant them in my regular aquaponic media. Time will tell.

I am interested to see how this works.

I have 3 4x4 ft growbeds supporting a 300 gal fish tank. In 2 beds I have 1/2" lava-rock (American Countryside Red Lava pebbles). In one bed I have Hydroton clay balls. I washed the fines out of the lava-rock and the Hydroton before using (1/4" screen). The lava-rock works great. It's completely inert and has a very good porosity for bacterial support. I use the Hydroton for growing root crops and for plants that come in and out fast like lettus or cutting starts. As TCLinks mentioned, porous media comes up with the roots and needs to be picked out or lost. All the plants grow very well in the lava-rock and high winds don't blow them over (South Florida outdoors screened-in system)

I've had a quick play with grow stones and I was suspicious. They are pretty rough and if you rub them together they make a dust. When I opened the bag a cloud of glass dust came out and I was very concerned about breathing it in. The dust/shards also concern me with regard to what they would do to the pump impeller over time (and fish gills).

I think that the flood and drain action of aquaponics would probably cause them to rub against each other and break down over time, which seems to be what happened to Dave. They float, and every time the grow bed fills they are going to move around and rub.

They are definitely very lightweight and hold water well though. I love that they are recycled. I'm sure they would be great in some dirt garden applications, but I don't plan on using them in AP. Not much fun to work with without gloves either. I would be interested to hear if anyone has used them in wicking beds, they could be great for that, but even then I would be worried about abrasive action cutting up plant roots every time you dig around. Mixing them in with wicking bed soil could maybe work well.

Yes, I am using Growstones and I have to add about 7 ml of Botanicare pH Down *every day* in my 50 gallon system to keep the pH from climbing above 7.  It is getting tedious.  My kale and tomatoes are not happy.  Next year I think I'll try something else, although I like that the material is recycled and from the US.

However, first I used Mother Earth hydroton, and that was a DISASTER.  At least with Growstones my indicator solution is not "pegged" at the low end like it was with the Mother Earth product.


   What is the pH of your source water?  What is the pH of your source water after you let it bubble for 24 hours?  I would not expect to need to add pH down continually to a system with grow stones, at least I didn't.  Are you sure the problem is from the grow stones?  I know people have used grow stones quite successfully for hydroponics so I wouldn't expect it to have continual long term pH issues.


I have learned that people do not always tell the truth in life. So, I applaud you for trying growstones and sharing your experiences. Normally, I have stopped testing for pH and accept what I have in my fish tank.  I will be draining my 300 gal fish tank that has had a Growstones grow-bed for almost 2 years. I am interested to see how the shards have accumulated in the bottom.I have switched to Grow!t, because of costs.


Whatever the name. it is about 1/2 the cost of growstones.

I am growing great tomatoes, peppers, herbs, and cantaloupe over the side.

Looking forward to my winter crop

Randall Wimbish and Dave Story , did you ph test your Grot!t media.

no. I just live with it. I test my microgreens. So if you want it, I will test and let you know, later. both Plant!t and growstones? both are established tanks

My belief is plants like lower pH (5.5-6.5), typically.

Tilapia like higher pH.

My city water is about 7.0

I do not add anything to my fish water. I accept it as is

I am trying my first season of sweet potatoes, some leaves are showing signs of iron deficiency. Everything else looks great. My moringa and date palms are fantastic. 

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