The Best Plant Growing System?

[Ravnis]

Oh, btw, in fairness to Rakocy and UVI, they may be feeding purchased food because it is a easy way to control nutrient input and the feed is still a very small % input cost. Depreciation of plant is usually the most significant cost. May be a trade off.

m

That and its really hard to quantify algal concentrations if it just forms in a solution. I would suspect but have no way to really measure that algae,like food, will lose some of its nutritional value when dried and processed.

[GaryD]

Hi Ravnis,

You can read about Ronald Zweig who did some work on growing tilapia in solar ponds (translucent fibreglass tanks)........here.

Gary

[Ravnis]

Thanks for the link, Gary. What I did was combine the green water technique with the aquaponics system.

Before anyone goes wild with this idea they might want to checks out these links.

http://www.aquaponicsjournal.com/articlegreenwater.htm

http://www.bioone.org/doi/abs/10.189...A%5D2.0.CO%3B2

I founds some old posts back in 1999 where Dr. Rakocy advised against combining greenwater with aquaponics as it would clog the gravel. I can't tell whether he used worms in his growbeds. All I know in my one time observation, it did not happen and the growbed flourished. I was even able to start cuttings in the growbed. I believe do to the worms. Also I suspect the aeration added by the flood and drain probably offset night time oxygen depletion by the algae. Something threw off my FCR rate as it was way less than 1. What ever it was, it made the economics of aquaponics much better.

Regardless, I do not recommend this process to someone starting out. At least till I run some more tests this summer.

[GaryD]

Hi Ravnis,

For me, the article says more about the ruggedness of tilapia than anything else.

I approach aquaponics from the perspective that water quality management in the fish tank is the absolute priority. I'm inclined, therefore, to rule out anything that diminishes water quality.....and by the sound of it, that includes greenwater (as things currently stand).

That's not to say that there's not some merit in feeding fish algae.....but rather than it would need to happen in a different way.......like pelletising it or something similar.

By the way, I think some of the things that some people believe about aquaponics......like using grow beds to process fish solids (as distinct from removing them and processing them externally).....are driven by outdated information based on tilapia production.

Few fish are as hardy as these creatures and I think that, to premise aquaponics 'guidelines' on tilapia, is a mistake.

Gary

[kellenw]

Most of the tilapias consume algae and diatoms as a pretty substantial portion of their diet in the wild. Tilapia are fairly capable quasi-filter feeders, but they rely quite a bit more on filamentous algae rather than suspended types. Tilapia are commonly grown in greenwater by fish farmers in many countries around the world. However, to get fish to harvest size in a single season in temperate areas, a high protein diet must still be provided as a primary part of their diet. Trying to grow tilapia using greenwater as their exlusive food source would result in a very disappointing fish crop.

Tilapia are indeed one of the most hardy fish we see used in aquaponics (wrt water quality, dissolved O2, etc.), and I tend to agree with Gary that they probably skew some "results" of backyard enthusiasts, causing them to think they've found a better way. I've stocked tilapia in my systems that I setup and filled no more than a few hours prior, ZERO cycle time, and I've never lost a single fish. Try the same thing with many of our North American native fish, and the "results" will most likely be a massive fish kill.

[DaveOponic]

The last two posts are very interesting. I started my Aquaponics journey with about 12 small Tilapia fingerlings and joined this forum at about the same time. I can remember being a bit intrigued about all the attention and advice on this forum about "cycling". I hadn't cycled my system at all, just put the fish in the tank and hooked up a couple of NFT pipes I had previously used in a DIY Hydroponics setup.

What I know now is that Tilapia are survivors and they are a very hardy fish. They are not detested here as a pest but on the other hand there are plenty of saltwater fish in the markets so the Tilapia is an undervalued species except by the indigenous people on the river who do farm Tilapia and many other local species including all manner of carp, catfish and strange freshwater species that grow bigger than us.

I recently joined the Malaysian Aquaponics forum. Discovered the forum from Affnan's Aquaponics Blog. Affnan has some good ideas suited to this part of the world and the species that are available here.

There is some interest in Jade Perch in Malaysia. I am not sure how well this species is suited to the hot tropics but I would like to try it in my AP if I can find a supplier in Brunei.

From keeping Barramundi last year, I learned the importance of solids removal and filtration after losing about 20 fingerlings due to poor water quality.

I am overdue in restocking with Barra but should have 100 - 200 fingerlings next week. I will then move all my Tilapia to their own tank and keep one system exclusively for Barra with more filtration and aeration.

[GaryD]

Hi Dave,

There is some interest in Jade Perch in Malaysia. I am not sure how well this species is suited to the hot tropics but I would like to try it in my AP if I can find a supplier in Brunei.

I would think jade perch would be a perfect fish for your environment. They are native to northern Australia.......and they do best in warm water.

In fact, you can often expect dead fish once the water drops much below 16 degrees C.

In warm water, they eat lots and grow very quickly.......like barramundi.

Gary

[TCLynx]

Too True on the comment about Tilapia skewing the recommendations!!!!!!!

So many people get away with what would otherwise be "fish murder" with any other type of fish but the tilapia survive.

I've grown both tilapia and channel catfish. I don't bother with the tilapia anymore (though I've thought about setting up a system that would breed lots of small fry that I could feed the chickens and ducks with.) We like the Catfish better, they grow bigger for us, are easier to clean and we like the taste a bit better though they are both completely mild fish.

Anyway, the catfish are actually quite hardy though they are more sensitive to dissolved oxygen levels and poor water quality, I've had very heavy loads in my system and they have done very well.

As has the plant growing parts of the system. I've been into trying all sorts of different things. It doesn't "have" to cost a lot. I'm actually quite happy using the plastic stock tanks as my grow beds right now. I use the deep ones so I don't need to buy or build stands for them. Just some concrete blocks under them so there is a little fall to drain them into a sump or in ground tank. I also tend to do things like grow trees in my AP system so the deep beds are a good thing.

[GaryD]

Hi TCLynx,

I've grown both tilapia and channel catfish.

I haven't come across many people who grow channel catfish. I'd be interested to know more.

Gary

[GaryD]

Hi DaveOponic,

There is some interest in Jade Perch in Malaysia. I am not sure how well this species is suited to the hot tropics but I would like to try it in my AP if I can find a supplier in Brunei.

Another fish that you might want to consider for your neck of the woods is the Marble Goby (Oxyeleotris marmoratus) which is supposed to be very close to our sleepy cod (Oxyeleotris lineolatus).

Like the sleepy cod, the marble goby is native to the tropics.

According to what I've read, they are also very highly regarded when it comes to eating......and there's a bit of literature available on Google on farming them in Malaysia

Gary