Backyard Aquaponics
A place to discuss aquaponics

Peter Sellers made a movie, named 'the Party'. You remind me of that movie, Nannoo. Thanks for that.

That self same document Nanniode... states at the density quoted...

In a 5000 gallon (18,000L) tank... 2500 pounds of fish... 1100kg... fed at 1.5% of body weight...

Would require a flow rate through the tank.. of 5.600 gallons per hour... 22,000l/h....

And would still require additional aeration....

Yes you have about 3 times the water volume... and currently only about 1/3rd of the biomass....but you're only turning over a bit more than 1/6th of the required water volume per hour...

Your supplementary aeration is probably only about 20% what you should have... or will need...

And it's air you're pumping... not oxygen... air is only 21% oxygen...

The only thing saving you currently.. is the fact that your biomass hasn't (as yet) reached critical in terms of oxygenation.. and your feed rate... and your feed protein percentage is very low...

P.S... water hyacinth may filter heavy metals... and "denitrify" your water...by sucking up nitrates...

But it is not, and will not bio-filter/provide nitrification...

He he... I am not repeating here the Peter Sellers famous line "In India we don't think who we are, we know who we are!" - the character's Bakshi's reply to a hostile "who do you think you are?"
Domani, it is funny that you compared me to Bakshi?

If you were to stock 15000 tilapia @ 0.4kg.... a biomass of 6000kg... feeding at 1.5%.... 32% protein...

Then you'd be feeding 90kg of commercial pellets.. per day... (you work the rest of the figures from that)

God only knows how much moringa (and laxatives).. you'd need to match that sort of feed rate/protein provision....

Do you mean I should have a 5.5 hp pump, ideally? That is 10 times bigger pump to have 15,000 fish in the system. Oops!

Feed is okay, IMO Rupert. Per my understanding, I am giving 42% protein solid diet, plus there is moringa/algae/hyacinth natural supplement for which we do not have an account for now. Growth is fine... I compared with the fish growing at a nearby aquaculture pond. We started together.

Sorry.. but based on the feed formulation.. and feed rate.. you posted...

You're not any where near that 42% protein...

Despite what you claim... coconut oil has no protein (copra does)... neither does peanut oil... and rice bran has only about 8%....

Given your feed formulation only has 5% of moringa content.. the only real protein source....

You're feeding your fish a low protein, high vegetable, high fat laxative diet...

Hence they're growing poorly.. but probably shitting really well... and easily...


Then the pond based system is also under feeding...and exhibiting poor growth...

Nanniode.. at this point... if you really wish to maintain your current stocking density... or increase it....

I seriously suggest that you engage a RAS consultant...

And again.. seriously suggest that you should not play with other peoples money.. by presuming to be a consultant... either RAS aquaculture, or aquaponics...

Just cut your stocking way down... grow some fish and plants in a backyard aquaponics system... and be happy...

What you are saying is incorrect, Rupert. Google for oil cakes, moringa, rice bran composition. There are several other cheap and locally available feeds under testing such as soya-bean meal, organic cow-feed pellet, etc. Here is a sample.

I malign rice bran... it's apparently 13%,, not 8%...

http://ingredients101.com/ricebran.htm

Coconut oil and peanut oil ..

They are not oils... oil cakes http://www.thefreedictionary.com/oil+cake
a cake or mass of linseed, cottonseed, soybean, or the like, from which the oil has been removed, used as food for livestock.

This is rice bran at 16% protein and several others including iron at 15%.


And, moringa, other than a laxative as you said, look at what they have.
"100g of fresh Moringa leaves have 8.3 g protein, 434 mg calcium, 404 mg potassium, 738 μg vitamin A, and 164 mg vitamin C" wikipedia. I am lucky there are plenty of trees growing.

Feed-wise, I am happy and going to continue the same feed for another 4 months for this batch of fish.
Fish diet regimen - ricebran+coconut oil cake+peanut oil cake+moringa leaves+hyacinth leaves. I might add soya-bean meal to the diet starting next week but no other changes for now.

I'm trying to find where you posted your feed formulation.. and ingredient percentages...

When you posted it .. you specifically listed rice bran, coconut oil, peanut oil... 5% moringa... and something else...

It's not the moringa I'm referring to as a "laxative".. it's all the oils and bran...

Perhaps the "something else" was "oilcakes"... but from memory.. it only constituted 5% of your feed...

You can't add the individual protein percentages of each ingredient.. to claim a 42% protein component...

When each ingredient is only a percentage of the overall feed....

Ah.. Ok found it... and yes.. you did say coconut oil cake... and peanut oil cake...

from your blog site...



So 60% of your feed formulation.. is comprised of an ingredient that.. at best... contains 16% protein...

And why would you feed Tilapia a 48% feed anyway... a standard feed for Tilapia is 32%...

Only trout, Barramundi.. and other really fast growth rate fish would require a 48% protein feed...

And a feed formulation is ultimately governed by the limiting amino acid profile anyway...

And we.. and you.. have no way of knowing what that is in your formulation...

Actually I'll take that back.. as it maligns the pond grower...

His stock is probably growing at the rate appropriate for pond based growth...

Your stock should be growing at RAS based growth rates... (it's not)

So effectively... you're not performing any better.. growth wise.. than a pond based system... with natural feed...

How much more money are you spending on feed.. just to get the same growth.. compared to the pond based grower...

You're probably not going to get any more for your fish when you sell them.. (if you get to that point )

So all you've achieved out of all your expense... is a few hundred plants to eat...