Backyard Aquaponics
A place to discuss aquaponics

Yeah, my bad, I got to thinking about this after I posted but was headed out the door. I guess the only time it would matter is if you were scooping straight into the growbed (very few are this fortunate).

the lava rock worked well, i dumped about 1/2 cubic ft at a time in a bin, and drilled about 50 holes in the bottom, and rinsed well and after 10 cubic feet total no red tanks at all.

Any issue with these pebbles?

http://www.homedepot.com/p/Vigoro-0-5-c ... /100558618

I was thinking of putting this on the bottom of my bed with a layer of Hydroton on top. Thanks.

River pebbles have been used here on the forum and cant remember anyone having issues. I think it always pays to do a vinegar test but it looks good to use.

You will do better for your pocketbook if you find gravel in bulk, as those vigoro bags can add up fast. I get their red lava rocks when I need a little more media, but to start off a system bulk gravel is far cheaper.

I switched from gravel to hydroton and wish I never would have. The gravel seemed to give the plants a better root hold.

I have some hydroton in waiting,ie in a mesh bag in my fish tank, waiting for my indoor system to come together ($). Less root hold maybe, but so easy to shove your hands into. I would say that is great for "high traffic" grow beds. I certainly would not try trees in it though!

I will only have a single 30 gallon grow-bed for now so my pocket book should be ok.

I've never heard that before... Normally it's the complete opposite, people wondering why the didn't change years ago..

I have 15cm of pebbles on top of 30-40cm of lava rock. Its great on the hands but now I'm experiencing lava coming up when pulling out plants. Not so much of an issue as you can just bury them again.

The light weight media compared to the clay balls I expect is something that kinda depends on what the primary plants are.

Growing bananas, papaya or Corn or even some of my tree size Kale, I don't think I would want to do that in a bed of clay balls.

However, after watching some people flood a bed and them simply swish a transplant down into the clay balls rather than having to dig, well that has it's appeal if only I could afford a container load of Hydroton.
I'm kinda splitting the difference as I can get Expanded Slate by the ton (1.33 cubic yards) and pick it up at local rail yards for about the same price as 2-3 bags of Hydroton. The Expanded Slate does tend to cling to the roots more like lava rock or the clay balls while the smooth river pebbles are smooth and let the roots slip free easier. The Expanded Slate is much lighter than river pebbles but a little heavier than clay balls.

Anyway, as charlie says, you probably want to get just one bag of river pebble first so you can rinse off a hand full and drop it in a glass of vinegar. You do this to check and make sure there isn't a bunch of limestone or marble mixed into the batch. If it fizzes a lot, it is a bad sign and indication that the rock would keep the pH in your system too high. If no fizzing then the rock is probably mostly quartz, granite, or basalt and will likely have little/no effect on system pH.

Lightweigh Expanded Clay Aggreagetes (hydroton, hydrokorrel, claypebble, goldlable etc..) comes in different shape, size and texture, I normally use the rough for this purpose and I have a bed of smooth to test differences, as you can inmagine the more round have less grip of the root, but like somebody said...heasy on the baby hands! and if you have strong winds in your area I would not recommend, yet easy to transplant because you can pull up a plant giving minimal root shock (the roots that get ripped off)
On the market there are options this day, river pebble are heavy but indeed cheaper and long lasting (hydroton becomes brittle and degrade over time)
Anything rough will give better root hold and provide more bacteria surface.

I've never heard of hydroton degrading over time. Has anyone experienced this? I suppose in many years it could.

To be more precise we are talking about a few years...my guess it's it will loose 1/10th of volume every ten years, yet river pebble would stretch at least 100 years before they are considerably degraded.
Sorry ...too technical sometimes! I should sleep at night instead probably!

Aside from chipping etc I would assume expanded clay would degrade. The only reason I have for saying this is that bricks do degrade, given certain ph conditions. I do not consider this would be rapid or significant given the likely decay period. I don't use them much so this is only imho.