I am just getting into this Aquaponics thing...it is really facinating to me. I am 43 and have never heard of it till a couple of months ago. Since then I have been reading up on the subject and had some questions that I can't seem to find the answer to.
I have seen that some gardeners are pumping their tank water it directly into the grow beds. I have also seen growers that have a raft system that is placed directly on the fish tanks. My question is; which way is the best way to do it. I have seen that some growers pump the water into a settling tank and then to the grow bed. What is the best method?
Also how long do you need to keep the water in the grow bed before it is safe to go back to the fish tank. Is the bacteria working in the grow beds while the plants are being fed or is the ammonia bad for the plants and should i put them in a biofilter before I put them in the grow beds.
I too am new to AP, I have a 180 gallon fish tank with what started out with 30 catfish, 4 to 6 inch in size, I am down to 13 fish after some pump trouble and ick that I got from trying to speed cycling with the help of a neighbors goldfish pond. Turned out the goldfish had ick... I started out with one grow bed 5x3x1 ft..have since added anothe bed same size. I planted right away and one month into it I have acycled tank, am harvesting lettus and have small tomatoes, I pump from the fish tank into the grow bed on for 15 min off for 45. The water from the grow bed goes straight back into the tank. I alternate the pumping from one grow bed to the next (using two pump). This keeps the water flowing in the tank for air. I have heard it's not good to use two pumps incase the timing gets off..but I have ran them both at the same time and my water does not seem to drop enough to bother the fish. I am loving it.... but not with out all the help I have gotten from this site... you post a problem and they all pitch in with a solution... great people here...good luck..and enjoy
You described 3 basic types of systems: raft, passive, and media. There are actually more types (I'll start helping instead of confusing in a minute): NFT, which is a system using pipes as a growing spacel; Vertical, where everything is stacked or in vertical pipes; Mixed, combinations of 2 or more; and Aeroponics, (which should be used with other techniques) which is growing in air. We normally recommend a media bed that either has a bell syphon (ask somoene else about them), or a timer, or even an indexing valve (ask TCLynx). As to the biofilter question, NH4- is perfectly fine for plants--they can even take it up in the vegetative phase. All you'll need to do is plant the plants in the media bed. We recommend a media based system because worms and microbes can brake the solid fish waste better in a media bed. There are other complexities, and there are groups dedicated to certian types of aquaponics, and have a wealth of information. To really answer your question, no system is the best system. Although someone will be bound to disagree on that.
The best system to start with is usually a media bed. The bacteria in the grow beds will do most of the work for you. If you use a flood and drain system and let it take about 15 minutes to fill it and then the siphon will kick in and drain it in about 5.
The growbed will become the bio-filter. Some folks do filter the solids but if your fish tank isn't overstocked it shouldn't be a problem.
The best system to use will depend on the situation.
For Backyard type systems though Media (or gravel bed) systems are good because they are pretty simple and the gravel bed acts not only as the plant growing space but also as your bio-filter and solids filter.