I have recently finished setting up my first aquqponics system. It is a 55gl food grade plastic drum for a sump tank in the ground, 55gl drum for a fish tank a 55gl drum cut in half for two ebb and flow beds and a round plastic tub about half the size of the drums as a radial flow settling tank it has an 800gph pump. I am using goldfish to start and have about 22 about 2 inches long. I plan on this being a challenge and probably have some failure along the way with ph swings, nutrient problems and anything else that could go wrong and I will learn and carry on but I have a couple of questions if anybody has the advice to give. First would it be of any benefit to add a couple of crayfish to the fish tank and the radial flow filter to help further break down the solids. Second would water snails be any benefit to the system. Third how many more beds do you think I could add to this system. And of course any other advice would be appreciated.

I would say no to the snails, I've heard they can become a tad invasive and clog plumbing. Crayfish do fine in aquaponics systems (I'm not sure how they behave in the same tank as the fish), they'll eat up some of the extra solids.

There are a lot of factors that go into determining a growbed to fishtank ratio (amount of fish and how much they're being fed, how many plants you have, what kind of plants, etc.), but I'd say you could get at least two extra growbeds to run off of your current fish tank.

If I'm remembering correctly, a radial flow filter helps to remove solids from your system, not break them down. It fully depends on what kind of system you want to run. I like to default to keeping my solids contained in my system (why waste extra nutrients?). If you're looking for something to help break down fish solids, have you looked into introducing composting redworms (Eisenia fetida) to your media beds?

Hey Alex, in hind sight I probably didn't need a radial flow filter for this system I guess I just got caught up in building stuff but I figured that since that is where most of the solids will end up it could be a good home for a couple of crayfish, and your probably right about the snails they could just go wherever they wanted. I am planning on putting red worms in as soon as the plants get a little growth on them. While we are at it do you Alex or anybody else have any thoughts or info on natural/organic inputs to help add nutrients to the system, I've read of some people using egg shells and lime juice to control PH and using dried banana peels for potassium, what about potash and other soil amendments would they work and be safe for the fish?

If you find yourself in need of nutrients, I've found water soluble kelp powder to be a great amendment. I've also used actively aerated compost tea to supplement nutrients and introduce new microbes to my system.

Eggshells are fine for aquaponics, although I've found they keep the pH a little too high for my taste. I'm starting to prefer running my system at 6.0-6.4. Seems the lower I swing my pH, the better everything does

Before we figure out what supplements work best, I'd like to ask about your source water. Are you using city, well, or rainwater? Well water, for example, is usually quite hard, and won't usually need added calcium or potassium (you'll find yourself going through more acid instead). Rainwater will need to have calcium and potassium supplemented regularly in some form.

I also would mention that lime juice is a "no-no" when it comes to aquaponics. We're building a system that thrives on bacteria and lime juice is anti-bacterial and therefore counter-productive.

Well my water is a mix of a couple of sources. My system is in a small green house and I have a dehumidifier that dripped in the sump tank while I was building the system and filled it buy the time I got the system built, the fish tank was filled with city water, and the rest came from our gold fish pond. Good point on the lime juice I definitely want my bacteria. Thanks again for all the advise.