Media

[TCLynx]

For those people setting up new systems, there are just a few things to keep in mind when choosing media.
Primarily, you want media that won't mess with your pH too much. Things like limestone and marble will tend to keep the pH in a system very high due to their calcium carbonate, normally such medias are to be avoided. Shells might not be quite as bad but I still wouldn't recommend them as media, they keep the pH up around 7.6 which is still higher than most plants really like and causes Iron lock out requiring regular additions of Iron to the system.
There are also some medias that have a very low pH tendency, Diotamite or Maidenwell is an example of this. Using such a media will require careful observation and buffering of pH to avoid crashing the bacteria and having terrible ammonia spike.

So before you buy a truck load of the gravel, you might see about getting a small amount to run some pH tests after letting the media soak in water for a while.

FYI pea gravel usually refers to the size of the gravel, not the kind of rock, around here cheap pea gravel is likely to be limestone. Mostly quartz type river pebbles of 1/2" and smaller size are usually a fairly good choice for gravel media. Granite can also be good as can lava rock of appropriate size.
Be sure to wash your gravel before putting it in.

Perlite is generally not recommended as it can be difficult to contain and vermiculite breaks down easily. Of the manufactured hydroponic medias the expanded clay balls of high quality are the only really recommended by many Aquaponics enthusiasts.

Coco Coir, Peat, Sand, wood chips, leaves, and other such medias are generally thought to hold to much water (keep it to wet for the plants) and may also leach undesirable tannins into the water. If trying to use any of these please do it on a small scale in an experimental set up when you can easily take it offline or remove it from the system if something doesn't go right. I once tried wood chips in a small experimental set up and they turned the water so dark that I could not see the fish.

Please add more tips and tricks about media here.

[TCLynx]

While more surface area on a media can make for better nitrification bio-filter in a smaller space, most of the size of grow beds needed for flood and drain media systems is actually needed for the solids mineralization and therefore the gravel being a bit smooth in a properly sized and stocked system does not make much difference since there is an over abundance of surface area for the bio-filter if there is enough space for all the solids and plants.

However, if you are removing solids and trying to squeeze the most fish possible into the smallest space possible and need it all to be as light as possible, they trying to make sure your media has the most surface area possible might be worth while.

[David Hart]

Help....does anyone have a link to a (stateside) supplier of coir ? with a decent price and shipping costs ?
Thanks !

[TCLynx]

I'll be interested if you find a good one as I think I want to test out more of it for seed starting and baby greens trays.

David Hart said:

Help....does anyone have a link to a (stateside) supplier of coir ? with a decent price and shipping costs ?
Thanks !

[Harrison Wayne Griffith]

hi I was at a play ground the other day and saw that they were using old car tires chopped up into small peaces and gave the kids something soft to land in.  I know that they have been using tires for artificial reefs for years.  That lead me to think that they would be ok for my fish.  I think they would work in my grow beds.  Do you have any thoughts on this idea?  Thank you  Harrison

[George T]

I could be wrong but I think it's been quite some time since tires were used in artificial reefs, mostly because they don't stay where they are placed.  Google tire artificial reef and the word disaster is frequently found in the articles.  No way could I use a petroleum product as bed media and then have any peace of mind about eating the fish or vegetables.    

Harrison Wayne Griffith said:

hi I was at a play ground the other day and saw that they were using old car tires chopped up into small peaces and gave the kids something soft to land in.  I know that they have been using tires for artificial reefs for years.  That lead me to think that they would be ok for my fish.  I think they would work in my grow beds.  Do you have any thoughts on this idea?  Thank you  Harrison

[Michelle Silva]

I found the stalite to be less expensive then gravel, but had already used coco coir in the system by the time I found the fairly local source to get it.

George J. Thurmon said:

That would be around 1400 USD just for hydroton.


You might want to research Utelite (expanded shale) and Stalite (expanded slate). Either of these would have a much greater surface area than gravel and are lighter - cheaper than hydroton. There was some discussion of these media on the BYAP site.

I'm tentatively planning to try Stalite - PH neutral. It will be more expensive than gravel but I want the most surface area I can get in the grow beds and a textured surface greatly increases the surface area. More surface area should equal more bacteria.

[Michelle Silva]

I did use the stalite  in a few stackers (mixed w/ the leftover chaff from coffee grounds). The plants seemed to have similar growth rate and  it was cheaper. The chaff held the water a little better then just stalite on it's own but can't use too much, tends to get a little sticky..(the stackers were fed the AP water 3x a day and recirculates back).

I noticed all the large bottom pots on the vertical stacks that have stalite in them (those were mixed w/ coco coir) have ten strawberry plants each and none of those are producing, while all the other 400 or so strawberries are producing (only have coco ocir/lg perlite). Although, the variable on that could be the bottom pot only get fed after going through at top, may not be getting enough nutrients...could solve that by adding another feeder tube halfway down stack. I'll add  more fish first before doing that. I have probably only around 175 fish (lost track) and LOTS of plants, so was happy to see the strawberries,tomatoes,peas producing. A couple of months ago, when system was still fairly new, borrowed a meter and it only read 550ppm...think strawberries need more then twice, will check again this week.

I also experimented with riverstone on one of the raft tanks and for some reason they didn't grow well. There were a lot of factors of why it may not have done well...I transplanted lettuce seedlings, they might have been too young, it was when it was hot still etc...although the transplanted in coco coir did well.
Michelle Silva said:

I found the stalite to be less expensive then gravel, but had already used coco coir in the system by the time I found the fairly local source to get it.

George J. Thurmon said:

That would be around 1400 USD just for hydroton.


You might want to research Utelite (expanded shale) and Stalite (expanded slate). Either of these would have a much greater surface area than gravel and are lighter - cheaper than hydroton. There was some discussion of these media on the BYAP site.

I'm tentatively planning to try Stalite - PH neutral. It will be more expensive than gravel but I want the most surface area I can get in the grow beds and a textured surface greatly increases the surface area. More surface area should equal more bacteria.

[Michelle Silva]

oops, didn't mean to write that I used chaff "from leftover coffee grounds"..meant from the local roasters, the leftovers from processing the coffee bean..it was also a free source.

Michelle Silva said:

I did use the stalite  in a few stackers (mixed w/ the leftover chaff from coffee grounds). The plants seemed to have similar growth rate and  it was cheaper. The chaff held the water a little better then just stalite on it's own but can't use too much, tends to get a little sticky..(the stackers were fed the AP water 3x a day and recirculates back).

I noticed all the large bottom pots on the vertical stacks that have stalite in them (those were mixed w/ coco coir) have ten strawberry plants each and none of those are producing, while all the other 400 or so strawberries are producing (only have coco ocir/lg perlite). Although, the variable on that could be the bottom pot only get fed after going through at top, may not be getting enough nutrients...could solve that by adding another feeder tube halfway down stack. I'll add  more fish first before doing that. I have probably only around 175 fish (lost track) and LOTS of plants, so was happy to see the strawberries,tomatoes,peas producing. A couple of months ago, when system was still fairly new, borrowed a meter and it only read 550ppm...think strawberries need more then twice, will check again this week.

I also experimented with riverstone on one of the raft tanks and for some reason they didn't grow well. There were a lot of factors of why it may not have done well...I transplanted lettuce seedlings, they might have been too young, it was when it was hot still etc...although the transplanted in coco coir did well.
Michelle Silva said:

I found the stalite to be less expensive then gravel, but had already used coco coir in the system by the time I found the fairly local source to get it.

George J. Thurmon said:

That would be around 1400 USD just for hydroton.


You might want to research Utelite (expanded shale) and Stalite (expanded slate). Either of these would have a much greater surface area than gravel and are lighter - cheaper than hydroton. There was some discussion of these media on the BYAP site.

I'm tentatively planning to try Stalite - PH neutral. It will be more expensive than gravel but I want the most surface area I can get in the grow beds and a textured surface greatly increases the surface area. More surface area should equal more bacteria.

[Johnny Hall]

 i dunno tires for playground us good idea or not , i have been to a tire chopping plant in jacksonvile florida and the chopped tires are full of sharp wires form the radial cord. probably ok for a driveway base but i would not want to be barefooted on it or fall down in it. only thing i have found good use for recycled tires is planting potatoes in and building earthship style structure.

i also think if done right 2 or 3 layers of tires set and filled with as much earth as they will take would make a fine above ground pond wall. you would have to check each one closely for snags of wire and nails but other tires could be skinned out

and used as caps for the voids in between each tire set. say you have a run of tires for retaining wall OOOOOOO cut out tire center and split the flap, use the flap ( i call them gators) to cover the voids in your tire wall run. just use flathead self drilling screws and it works great and goes quickly

 

but for media i dont think so , im still hopeful this plastic grid i made will work out , its old bread trays and milk crates tied together and then top dressed with standard media type rock. so far its looking good and i figure has cut my weight down

1000 pounds per bed. time will tell but for now all is well.

 

best regards , john

 

Harrison Wayne Griffith said:

hi I was at a play ground the other day and saw that they were using old car tires chopped up into small peaces and gave the kids something soft to land in.  I know that they have been using tires for artificial reefs for years.  That lead me to think that they would be ok for my fish.  I think they would work in my grow beds.  Do you have any thoughts on this idea?  Thank you  Harrison

[TCLynx]

I agree that tires are probably not a good idea for media. I understand they can leach a fair amount of heavy metals into the water.

The stuff used for playgrounds has been shredded and the metal taken out and then usually coated with something since naked tire material will make you very dirty or I should say make the kids very dirty. However, tires are very flammable and I know of at least one instance where an entire playground area went up in flames, at least no small children were present and the teens who were probably responsible for the sparking flame ran quick.

[Harrison Wayne Griffith]

Thank you one and all I will not try it.  The only reason I thought of it was to try to cut down the weight and it was something I could get local.  I will have to go with river rock. I would like to use the expanded slate but can't find any local and shipping puts the cost up.  Harrison

TCLynx said:

I agree that tires are probably not a good idea for media. I understand they can leach a fair amount of heavy metals into the water.

The stuff used for playgrounds has been shredded and the metal taken out and then usually coated with something since naked tire material will make you very dirty or I should say make the kids very dirty. However, tires are very flammable and I know of at least one instance where an entire playground area went up in flames, at least no small children were present and the teens who were probably responsible for the sparking flame ran quick.

[TCLynx]

Other than the weight, river rock works very well.  And you can always think of it this way, river rock will easily support tall heavy plants while something light may allow stuff to tip or blow over.

Harrison Wayne Griffith said:

Thank you one and all I will not try it.  The only reason I thought of it was to try to cut down the weight and it was something I could get local.  I will have to go with river rock. I would like to use the expanded slate but can't find any local and shipping puts the cost up.  Harrison