Backyard Aquaponics
A place to discuss aquaponics

Mine are 4" with a 2.5" bell and a 1" outlet. They have worked flawlessly since installing. I drilled holes in the first few, and then table saw for last. I don't know how many holes I drilled, but it was a LOT. Guesstimate of 90-100 holes per media guard.I had some roots in one and I just twisted the media guard and pulled them out through the top. I have a threaded cap on mine to keep it clean and keep critters out. Don't thread it on more then a few threads or it will get stuck and you will have to get pipe wrenches to remove.

4 seems small to me, especially if (like me) it wants to tip slightly when bumped. Its like playing the old board game "OPERATION" when you were a kid.



Touch the edge of the media guard and Leca goes to your sump tank! lol



How does your 4" media guard hold to the bottom of the GB? just gravity alone that 4" pipe doesn't try to tip slightly and media slides under?


In my case the ribbed bottom of the GB is forcing me to trim little lips and edges to fit into the ridges.

I used rock for the the media, so no problem getting the guards to stay put. Just needed to be careful when shoveling the rock around them to keep them centered on the bell.

After calculating my total volume based on 9 bags of leca @ 40 liters each for a single GB = 360 liters because we cut our IBCs sideways. And 6 total beds... We are looking at 2160 liters of media required. So I'm going to use a mixture of media with clay on top and something cheaper on the bottom. I will make sure to do a vinegar test, as I have seen so many BYAP members write about.

As for the media guards. We have developed a method to make them not tip over, and from my first testing it also seems to keep them from floating with the clay, but a few inert rocks will hold them especially well now.

nice discussion and great looking build

Thanks Boss, I was looking at yours the other day. I get the idea we are going to see something BIG from you when its done!

Question... how would the media guard tip over if the bed is filled with media? The media you are guarding will create its own lateral support which will make tipping impossible unless you invert the entire bed. Also, the flat piece of plastic on the bottom looks like it is inviting an anaerobic zone underneath it. I recommend filling that piece with holes to allow proper drainage.
Just my $.02.

Squatch, your two cents is worth about .10 cents in my backyard. I thought the same thing about media holding it in place but... the clay is so light weight it wants to float and because the media guard is made of "foam core" PVC it tends to float when the media around it is also floating.

It will rest on the base of the GB just enough to use the flat surface instead of the rippled GB floor there today.

Basicly with the bed full if I push down on the ever slightly floating media it makes everything shift. The worst of the shifting is causing the media guard to lift directly upwards against gravity. And if its not resting on the floor then media can seep underneath during the drain.

Part 2 of this fix will be the addition of heavier real rocks on that bottom flap to hold it down and then clay media will go on top.

While the flap on the media guard is preventing tipping from the rippled GB base. It turns out it still has a tenancy to float upward during the filling stage and remains lifted above the floor of the GB while draining.

In fact when I watched your youtube video I kept looking at your media guards wondering about sizes and material. When I made my purchase I basically walked into the plumbing store and asked for the cheapest 6" PVC they had. I didn't realize foam core / cellular core would be nearly buoyant. The media floating made things worse. And finally the ripples in my GB floor were the 3rd contributing issue.

I think most people cut their IBCs in a manner in which the drain is near a flat surface, and if they happen to use clay which floats when its brand new, their media guards are probably made of solid PVC and they may not experience this is quite the same way I did.

I made yabbie and prawn traps out of foam core pvc off cuts from my build.... Threw them in creek.... And they floated.... I can feel your pain!

Okay, if you keep the flat piece on the bottom of the guard and fill around it the media should hold it down. Are you doing your testing with the bed full of media or only partially? I find it difficult to believe a bed full of media would float like Styrofoam on top of the water. Surely, the collective weight of the media will hold down the guard as well as the media on the bottom.

One thing you could do is fill the bed with media and run the water on a constant flood but with a short stand pipe (maybe half height). Allow the bottom media to water log and then increase the height of the stand pipe to water log the remaining media.

I just haven't heard of folks having this much trouble with expanded clay before.

Oh.... you still need to fill that flat piece of plastic with a bunch of holes.

EDIT: Don't know if I told you before but... I used 6" for media guards, 3" for bells and 1.5" for stand pipes.

I can probably show it on video. But yes its floating a bit, a lot of it has to do with where the water level is at. Basically the top of the media, when full of water, stays about 2 inches above the water line. So I added more media and cut the stand pipe a bit shorter. This helped a lot and so I kept making adjustments to the height of the stand pipe and fill level of the media.

Finally I let it soak over night to help the clay media to saturate. This morning I moved them to a new GB, all the floaters first. And then I took the very small percentage (5%) that had sunken to the bottom of the GB and decided to put those in my net pots for my DWC.

When I searched here on BYAP for "floating clay" there were a few people with issues and most times cutting the stand pipe helped.

I am going to cut holes in that flap as you mentioned too, it can't hurt and wont take that long... more cow bell, some might say.

Who would say such a thing? I would suggest finding scoria as your bottom media. I actually prefer it to clay. It has been over a year, and I still have ph issues with the hydroton... My outside beds with the scoria have been fantastic.

Aye Aye Captain Maggi, Didn't you make a sleuth box mining set up to clean it as well if I recall from reading your build thread?

The scoria is lighter then river rock at least and more surface area. I should test some of my clay's PH levels while I still have unopened bags now that you mention your clay alkalinity calamity jam. <this will be the name of my Band one day.

The clay left behind a ton of fine silt. I used two pumps (clean in/bad out) with the drain sealed off and floating actually helped with separating the junk out.

So I went to pick up some media, and comparing weight and prices becomes a bit more real to me. I shot a quick video of my vinegar test just because it was fun, but now I crave salt and vinegar potato chips.




Next post will be about how I ended up washing the dust off before adding it to my system.