Backyard Aquaponics
A place to discuss aquaponics

My first system, which I started about 2 years ago, was a "tester" system to see #1 - if I could do it and #2 - How I would do with it. Well, all went well so I just recently built a system in my basement so I could keep it going year round. (I live in Frigid Upstate NY USA)

Long story short...my first system was with Pea Stone. For the Basement system, I went all out and purchased expanded clay pellets. To my surprise, they float! I have an Ebb and Flow system with a bell siphon....they move around during the cycles and my plants fall over, or even worse, GET SWALLOWED UP by the clay pellets.

GB is 2ft X 3ft X 8in deep. I filled the GB up about 6 inches leaving room for dry pellets to lay on top and room from the top lip so nothing falls out or spills out.

How do you guys do it? What am I doing wrong?

Mischief

The clay pellets will float until that have been saturated with water. Try soaking the entire lot of them in water for 24 hrs. This should cause most of the to stop floating. The issue with Ebb and flow is that the clay can dry out during the long off cycles. Search the forum for ebb and flow as you are not the first to have this happen. You might find some fixes that other have done.

I was hoping that was the case so I removed them from the GB and have them in clean water in a separate tub. Did that last night so we'll see what happens tonight when I get home from work. FINGERS CROSSED!
Cool thanks!!

..
Crap... my clay is second hand.. and when i do bed floods to see what crawls out, even more clay balls float...
Disturb them and more float from underneath.. you will NEVER get 100% sinking. IMHO..

the answer is to only ever fill/flood to say 2" or some cm from the clay surface.. but do a heayy flood and stir the lot and let the floaters have their way and give them, their space, knowing they will likely ALWAYS float:
..
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I just read that the best solution is to fill the "void" under the pellets with pea stone, or something of the sort.

the problem is easy fixed, fill the water level up to your desired height, if the pellets float simply drop some heavier media in, eg: (15-20mm river stones) they will sink past the floating pellets and fill the void at the bottom, its so easy..

There are different clay pellets too, most of the Chinese stuff floats a LOT more than the European clay.. You could try dropping your water level a bit if it causes problems.

I probably have the cheap pellets as well, and found an easy remedy. did some tests on these things and found they start to float at a certain water depth....here's an easy solution..


the larger river pebbles added to the bottom would also assist with a better drainage......

I'll just add that I did contact the manufacturers of these clay pellets about 6 months ago (Growlush) to put a diagram on the bags of what to do if the pellets do float.. they do advertise that these are good for AP systems but unfortunately they float before the standard 250mm water depth is reached.....
They obviously didn't care all that much of what I suggested...

and soaking them I think is an old wives tale......IT DOES NOT HELP...

In the first GB that I started, over 2 years ago, I used all pea stone...HEAVY!!
The following year, I pulled some pea stone out and added some large river rock (1-1.5" diameter)....still pretty heavy!
So, I wanted to make it LIGHT WEIGHT and just use clay pellets BUT now I've added stone to the bottom again to take up the "void"....back to heavy

Mischief,

You say your GB is 2ft X 3ft X 8in deep and filled up to about 6 inches leaving room for dry clay balls to lay on top, you need around 2 inches of dry clay balls to stop any floating, the weight of 2 inches of dry clay balls will stop any floating. You also need that 2 inches to stop evaporation and algae forming from a wet surface, that would only leave you about 4 inches for plant growth which is cutting it a bit fine.

A 12 inch deep GB with 2 inches of dry clay balls on top will not have any problems with floating clay balls even using cheap Chinese media. I have only ever used cheap Chinese clay balls and have never had any problem with them floating.

What I do is set the stand pipe height approximately 2 inches below the clay balls, block off the stand pipe and fill the GB with water for an hour or so then let the water siphon and that stops any floating.

the floating only occurs when the full depth of the GB is full of the clay balls. not just the top 2inches.

Just about everything Growlush sells, including their lighting and electrical products etc, is sourced out of China, so I would assume the Growlush expanded clay is the same... and there is NO good quality clay coming out of there, not that I've seen anyway.

I have periodically stocked a number of the cheap Chinese and Thai clays, and seen, or been given samples of many others... they ALL float, and most also break down... they are CRAP!!!

I only sold these cheap clays during the period a couple of years back where there was no German clay available, and we had nothing but dramas. I'm now back to selling only sell German clay through my store, either Lai-flor, or Euro-clay, and we don't have issues with either of them. Some of the pellets do float, but a good majority of them sink.

Even with these quality German clays, the first couple of F&D cycles can see your gravel guard dragged up with the floaters that are working their way to the surface, especially if your max flood level in the gravel is too high. So the best thing to do before adding plants etc, is to put a brick on your bell siphon or gravel guard, so it can't move, rise etc, and run the system through a number of F&D cycles, the sinkers will sink, the floaters will rise to the surface, and as long as you are flooding to no more 40mm from the surface, everything will be sweet from then on... the same can't be said for the cheap clays.

YEP!!!... It irks me every time I see someone promoting or justifying the use of these cheap crappy clays by quoting that... They have obviously never tried it. I have tried it, with a number of the cheap clays, and even after a few days of soaking there is very little or no difference in the number of sinkers.

Like anything... you get what you pay for.

I just lower the level of the standpipe so the clay rests on the bottom of the grow bed again. Granted you don't get as much filtration volume but it works for planting.