Backyard Aquaponics
A place to discuss aquaponics

Hi Everybody
All progressing nicely with my new set up
Question re media:
I see that a Vermiculite/ Perlite mix is available
Has anyone tried this?
Is it better than one or the other?
What would be the advantages of it?
Or any comments

cheers
N

This sort of mix is not ideal for the AP systems that most of us run Notable. Both perlite and vermiculite hold water very well and therefore do not require the frequent flooding and draining that most of us give our AP beds (or the continuous flow that others have). The reason we flood so often is that we used the beds as solids and biofilters. IMHO you would be better off using gravel if you can handle the weight or clay balls if you cannot.

Tell us more about how you intend to run your beds.

Thanks VB
Fish tank 1500 litres, 2 X 150litre growbeds, submersible pump with gravity drain back to tank
I see what you mean about the water absorbtion of vermiculite, so I may go with Hydron for both beds and have a new seperate Verm bed for seedling raising
N

Although it may not look like it, perlite also holds water very well. Squash a piece between your fingers (after it has been soaking) and you will see. I agree that it would be best to go the hydroton if you are trying to save on weight. As for seed raising - I've returned to raising mine seperate to the system in a 1/3 mix of each of medium river sand, vermiculite and perlite. This mix comes of the roots very easily so suits out situation well.

I have a perlite mix in my system. it's running well, but the vermiculite can block drains, and the perlite floating is a pain in the arse. you need gravel to hold it down, so you may as well just use gravel.
it's very light though and easy on the hands, and cheaper then clay balls.
I won't be using it in my next system, too much hassle and the pluses aren't enough to make it worth it.

I am trying a bed of vemiculite at the moment i am running 15 min on 45 nin off 24-7 the carrots are booming the lettuce from seed are booming and a tomato cutting has taken roots also the lemon likes ap

I use a perlite:vermiculite mix at about 70:30, but only in the cups dropped into the NFT part of my system. I use scoria in the growbed part. When I run out of vermiculite I'll probably just use perlite on its own because it seems to hold enough water on its own.

I've got perlite; but in NFT cups. In the growbeds I've got good old expanded clay.

Has anyone tried using polyester insulation batts for grow media? You might need to pack it in tightly to allow enought plant support and would need to give it a while to drain between flood cycles. If it worked it would be a great clean and light alternative to rocks.

You could test out the bats and let us know what you think. I suspect that it might tend to clog up more with solids and be tricky to pull plant roots out of when getting ready to re-plant.

I could see the bats being thought of as clean when you put them in compared to gravel but they will very quickly take on a more wet, slimy, gunky character if being used as growbed media. Test a little bit out to see what kind of wicking properties it has. If it does tend to wick moisture to the surface, you will see algae growing all over the surface quickly. One might also want to check on what chemical treatments might have been applied to it to make sure they won't be harmful to fish or food production.

Very likely that they may have been manufactured with a "fire retardant".... which would be pretty nasty to your fish... definitely check it out first... or test it on a couple of sacrificial goldfish....

I didn't think of that - but it mustn't be too bad as I use some in my aquarium to filter solids and my fish (murray rainbows and empire gudgeon) are healthy enough.