Backyard Aquaponics
A place to discuss aquaponics

Just wanted to throw around ideas on increasing plant growth in AP. Be it adding more o2 to roots zones or adding stuff to the water. This will not apply to all systems, just some of the larger ones, or semi commercial.

I've noticed a lot of systems can stall. One solution is more fish. Be nice to borrow 500 fish for a couple of weeks to get your lettuce ready for market. Adding ammonia to a system would help but there are risks to the fish. What about running a bio filter with an ammonia source until it had converted it to nitrate. A seperate digester could work on converting ammonia and dealing with the solids removed with swirl filters. Is dosing a system with Na safe?

Foliar spraying works well in dirt gardens to alleviate some neutrient deficiencies and i see no reason why it cannot be used in AP ,, just need to ensure fish safe fertliser.
AHHH , not meaning to harp ,, but yes a foliar spray made from Moringa has shown great benefits.
I'll try and find the link.

Moringa work okay as a fish food.?

Moringa makes excellent fish food ,, I have used it extensively with Tilapia , but do not know how other fish respond .

Here is the link to the benefits of using it on plants http://www.tfljournal.org/files/Moringa ... %20(screen).pdf

I don't automatically believe it but we have had good results with vegies in Thailand using it as spray but I have not run " blind tests" etc.

The only way to really increase plant growth is to make sure that there is nitrate present, and a decent amount of minerals too.

Urea (in whatever form) and seasol / maxicrop - combined with very close monitoring of Ammonia, PH and Nitrite, will give you the best growth possible.

2c

There are several things, from various sources, that I have read that may pertain to this subject-
Additional O2 aeration for DWC will help ensure that things like ostracods won't eat the hair roots and help with dead zones from biofilm build-up, even of beneficial bacteria which can also cause dead zones.
Mechanically brushing the tops of plants to stunt leggy growth- the wind does this naturally.
Music to stimulate growth, especially hard rock- it's the music's vibrations that causes this reaction.
Using red colored mulches to encourage rapid fruiting in tomatoes and strawberries- plants are color blind but apparently they can detect the fruiting of other plants and induce the competition of propagation. I would assume that the plants can detect this through the bouce back of light waves. Every color wave length is absorbed differently.
Also for faster nutrient uptake, use down-draft fans directly onto the plants- encourages transpiration and reduces the chances of tip burn which is common in lettuce.
I'm sure I can think of more later.

Going to set up a 200ltr drum with an airlift bio filter(ABF) and add a little urea and leave for a week and see what happens. I will use some seeded media so the bacteria will already be there. If I can convert all the ammonia and nitrite it should be safe to dose an AP system. In NFT or DWC it could be drip feed in after the FT so the plants can take in a lot of the Na before it gets back to fish. Would replace Urea with a safer source of ammonia for long term use.

Does anyone know if the bacteria in compost tea would be harmful to the fish. I know its naturaly occuring but not in the amounts that are generated while brewing the tea. It seems to be good at breaking apart the compost and salts etc.

[quote="Dufflight"] In NFT or DWC it could be drip feed in after the FT so the plants can take in a lot of the Na before it gets back to fish. Would replace Urea with a safer source of ammonia for long term use.[quote]

As long as all the ammonia is converted to nitrates within the drum/filter I can't see why you could not use a venturi type feed into the line to your grow bed, put a tap in it and only turn it on when you have no or low nitrates. This is being diluted and hopefully used within the GB so would have no ill effect on your fish.

Guess as long as there is nothing that can stress the fish, ph etc. Then it could be put in over a few hrs and then the drum isolated and more ammonia added. An ABF can work with a single air stone in a 200ltr drum given enough time. Just wonder how strong the Nitrate can get if you don't have to worry about fish in the water while the bacteria is working. Be nice to be able to keep plants powering along over winter when the fish slow down. Or just for small periods. My orignial ABF ran in the pool for ages and could keep the bacteria on its media going and then moved to a seperate tank for bulk processing.
http://www.youtube.com/watch?v=HbXA0tFP ... annel_page
http://www.youtube.com/watch?v=E6cJFg4U ... annel_page

What media are you going to use in the biofilter Duff?

I strongly agree with OBO on the nitrates and minerals. I'm not sure what fish can handle and remain healthy but If you are reading all zeros on the water tests it's good for the fish but you would have to assume the plants are wanting. I am certainly not experienced enough to say for sure but I'm thinking if you can maintain at least a 1 ppm in nitrates the fish can probably tolerate it in a healthy manner and the plants aren't just sucking up plain water.

Just for general info...

Studies have suggested that elevated nitrate levels have NO significant detremental affect on fish.... at least with levels less than 500....

There is even some evidence that low nitrite levels (around 1), as long as mitigated by salt... may even have some beneficial affect on growth in some species... including Silver Perch...

Thanks, I probably would never try to push the 500 ppm level but after my first sytems plant growth trying to keep the levels close to zero I felt the plants were wanting.

Was going to use the 13mm poly cut offs. Out of the 2 it seems to perform better. The bio balls can get a build up over time. The cut offs are churning all the time and seem to have a macerating effect on solids. The bacteria has a good surface on the inside of the poly.