Aquaponic Gardening

A Community and Forum For Aquaponic Gardeners

I'm put together my first AP system.  Got everything bought or ordered and will be putting it all together in the next week or so as stuff arrives.  I was planning on using some left over gravel from a previous project as the media in the grow bed, but decided to do the vinegar test on it last night to make sure it was usable.  Looks a little like someone dropped an Alka-Seltzer in there.  So, I need some input on media to buy.  From what I gathered in my other research, I want something like expanded clay or expanded shale, about 1/2" to 3/4" in size.  I'm pretty sure I can get the expanded shale at a local pond store, not sure about the clay. 

First question, how much do I need for a 55-gallon barrel cut in half as my grow beds?  Second question, what media would you recommend?  Should I go with the expanded shale, or is there something that will work better for me (or as well and less expensive)?  Third, is there anything other than pH and size that I need to be considering when choosing the media?

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Hi Kerry,

These have all been widely addressed here

Thanks Harold.  I did a quick search before posting but didn't find anything relevant right off the bat.  Didn't realize there was a group for it already.


  My experience with Hydroton and LECA wereto give me fits, both are a great medium for aquaponics and both have their cons.  Hydroton is expensive and what people didn't tell me is that both float (LECA to a lesser extant).  I have more experience with Purple quartzite (doesn't float at all and is pH nutral).

  With the LECA and Hydroton, until they get water logged or the bacteria colonized after 3-months they seemed to settle somewhat but I was still getting both drained into the fish tank.  In the beginning I didn't ancor my mediua guard to the bottom of the growbed and lost media through the siphon so this may be an option for you to do so.  I use the bell siphon exclusively in my media beds and turned to the quartzite.  I can get it a lot cheaper than the imported Hydroton or the domestically made LECA.  If I would have went with the flood and drain without the bell siphon (water drains back through the pump or small holes in the growbed or bottom of the stand pipe) I would have been better off but to rationalize the cost of both medias I chose the less expensive, and quarried local, Purple quartzite.

Thanks for the feedback Leo.  I don't think I've heard of purple quartzite before now.

I found a local "water garden" store that carried the expanded shale so I went by there last night.  I explained what I was doing and he was familiar with aquaponics; he recommended the pea gravel as it was ph nuetral and was much cheaper than the shale.  So, I think I'm good to go for now.

Take along some vinegar and a jar when you go to get the pea gravel and test it.  The pea gravel around here has limestone in it and fizzes when placed in the vinegar.  Of course the sales person will say that the gravel is pH nutral, mine said the same thing.  Be careful, most sales people will tell you anything to make a sale.  I know I sound synicle but be careful.

I have another silly newbie question that isn't grow bed media related and probably should have it's own discussion.  The submersible pump I got has a filter in it.  Am I supposed to remove the filter so that the fish waste gets pumped out of the fish tank and into the growbeds?  Or am I supposed to leave the filter in and just cycle the non-solids?  If you take the filter out, how do you keep the fish from being cycled?  (I'm starting off my new system cycling with minnows.)

(Also, to brag a little, I got both of my bell siphons to work correctly on the first try! )

Hi Kerry,

Yes you should remove the filter, sending all the waste to the GB's. Get a container with a cover to fit the pump. Drill two snug fitting holes to allow the piping to enter exit the container to match the pump configuration. Cover the container sides by drilling many small holes through it. Basically you are encapsulating the pump within a plastic strainer which will allow waste into it but not fish.

Good job with the siphons......makes you a resident siphon expert now! 

Thanks Harold.


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