Backyard Aquaponics
A place to discuss aquaponics

Agreed Jaymie. I think it is probably the size that is the key even with other media....

Thinking about it, it's probably not so much a question of the smoothness or roughness of a media with relation to bacterial growth..... the bacteria will grow anywhere... even on the smoothest roundest river pebbles....

But more a factor of the increased surface area an irregular media (like gravel) provides .... more area, more bacteria...

The size and irregularity of the media does affect both the ability to retain water (and drain times) and more particularly the amount of oxygen retained.

A larger irregualar media size allows better drainage and greater oxygen retention (spaces) than someting finer.... ie....the surface area of sand is huge in relation to other media, but the type of bacteria we want to encourage wont thrive in sand because ti packs so densely that there just isn't enough oxygen for the bacterial process....

Ashley

Link to pdf on use in soil mix http://www.cwc.org/glass/gl9710rpt.pdf

It also references using it in hydro at the start but have not found that article yet

10mm is hard to get from recycled bottles though... That's the problem. I guess you could get small platelets of glass, 10 - 20 mm diameter, but only 2-4mm thick... I guess that'd work ok.

Can always use it as a mix with other media.....

4mm would work on a drip with hydro easily, about fishtank gravel size.
He was only looking for options and I think any use would be worthwhile rather than landfill.

Probably the best application at that size Sleepe

4mm is about hte same as vermiculite is it not?

I'd say give the 10mm a go.

I dont think there wouod be any bacteria surface area issues however the non porus nature may have a lack of water retention meaning shorter flood drain cycles.

This link has a pic of plastic bottle tops used in an aquaponics project (in a separate biofilter). They've been used in biofilters before, so perhaps there's work done on possible leachates from them.

http://www.egr.msu.edu/age/aenewsletter ... ponics.htm

The info is not only helpful here, but also motivating. Thank you.

Sleepe, thanks for the refrence to Crushed Glass...in Topsoil. I not only have to convince myself of these things, but I also have our local national park rangers and local council officers to convince; and when I can present something to indicate that I am not totally crazy (hey, look, others are doing the same thing) then that's great!!!

We did try a process that produced mainly 10-20 mm, with some hiccups, but I will try to get it happening again.

A "drip with hydro" was mentioned. Does that mean drip irrigation into the bed? Any reference to reading would be appreciated.

I am putting it alltogether this week, and will start with the fish in the bottom tank, pumped up to the plants, some with drip feed perhaps, others with intermittent feed, and just play with it. Some of the water will filter back to the fish and some through the worm farm which is suspended over the fish. I have noticed some of my African night crawlers wander; and these worms are used as fish bait normally.

Now for the long haul of trial and error.

Ashley
This was in reference to the 4mm glass, yes drip feed to the bed . About the same size as really coarse sand. Because its small it tends to retain moisture well, in hydroponics you only have to drip it in rather than high flow systems.
Problem unless controlled, drip feeds get blocked. Most people run plain water through on a regular basis to stop salt build up in the glass (sand) and to clear the lines. Used a lot in once through systems ie run to waste because it requires almost no controlls and very little expertise.

Can't find any thing at the moment but the site I got the other info from has some really good stuff about what to do with glass. link http://www.cwc.org/glass.htm