Backyard Aquaponics
A place to discuss aquaponics

I need help picking out my Gravel. Here's a short list any other choices? What are all the things that can be used?

Granite 1/4 inch
Granite 1/2 inch
Granite 3/4 inch
Granite 1 inch
Pea Gravel 3/8 inch

I like 1/4 pea gravel. It's pretty and small. Smaller gives your bacteria more surface area to cling to. Also it is not pointy.

Smaller the gravel, the less water it takes to fill the system, the smaller gravel keeps bacteria better, and has better support for your plants.

But the smaller the gravel, the harder to wash, and more it takes to fill the grow bed, but the + out way the - . Go with the cheapest smallest gravel you can find. That will be your best bet

-df

I've been going through the gravel debate myself. Locally any crushed gravel is cheaper than pea gravel. And I also like the fact that the sharp edges allow more area for bacteria growth.
One thing I'm trying to avoid is 'red rock' because of the natural iron and locally copper that can be present. So, I'm thinking small crushed. 1/4 - 1/2 depending on what I can get it for.


On the topic of gravel, how much does it take to fill a half barrel?


IF I can find a good price on Hyrdroton, I'm thinking about a layer of it across the top to help hold moisture and slow evaporation. But cost is the issue. Locally the best price I've found is $40 for a 50L bag.

don't forget, sharp edges will scrape your hands when you are planting. Depending on what your growbeds are made from, there may be some damage to them too.

I have been using PRO'S CHOICE SOILMASTER SELECT in my aquariums and it works great for that. I think it would also work for aquaponics but to fill a whole bed it would cost 3x the price of gravel. It would be a lot cheaper then hyrdronton but would it be food safe?

http://www.lesco.com/

I'm using a pond liner thanks for the advice, sharp stuff could cut up the liner over time.

I currently use 20mm gravel. In my new Tragic Greenhouse, i am inclined to continue with this (for ease of washing.) I may put a layer on top of finer stuff to make planting of seedlings a little easier. I like the thought of pea gravel, but i am on a budget and it is a lot more expensive.

Rassd is the iron bad for the crays? I know the copper is.

If the iron content is ok then it may be a bonus as you might be able to get away with not adding any iron to your system!

From what I've been told, the crays are extremely sensitive to ANY metals in the water. I've known people who've had all kinds of stuff in their systems. Brass fittings used as weights with no problems. But then you hear the horror stories of a farmer who had a great system going but used galv fence wire to tire together pieces for hides and lost the whole lot! So, I again err on the side of caution. The ONLY metals I will want to have in contact with my system are 1. Stainless 2. Titanium and three in limited contact if necessary Aluminum. Because I had aluminum in a closed system for months without problems.

Hey BF... I have found that gravel makes the GB incredibly heavy....

I use scoria, it is light, and it makes a great place for the bacteria to live and the roots to hold onto. It is very kind on your hands and doesn't damage the growbeds. AM uses gravel and his plants took a lot longer then mine to pop up, so it is great for planting seeds. Also it is very absorbent so the water stays it it for longer so that way when the water level is low the top layer of scoria is still fairly wet.

rassd, maybe try a small tank, say a 3 foot aquarium, with a small bed of red rock just circ. over it. don't worry about the plants or anything if you don't want. stock 10 crays and see how they fare.

do this while you're setting up your system

seriously though, it won't make any sense to avoid iron then to add chelated iron when your plants are going yellow

but i get your cautiousness

I use a mixture of gravel sizes:
Bottom 100mm(4") has 20mm(3/4") gravel, this allows for a nice flow of water to the drain pipe and back out of the GBs.

Remainder with 10mm (~1/2"), apart from the odd broken finger nails :limpwristed: :blowingkisses: , I have not found any problem in planting seeds or seedlings in the gravel

At some point, I'll test out different things. Right now my breeding stock is just too limited!

fair enough rassd