Backyard Aquaponics
A place to discuss aquaponics

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Sorry - no idea if it has had a number put to it, but i'm planning a Grow-Bed-Less Aqua-Culture System

The rule of thumb is that you "Should" have about 25L (/30L) of media per intended fish..

If you are collecting ALL the muck and using Off-Line mineralisation, I assume that there is still a need to knock out the ammonia that comes direct from the fish and which can't be removed in swirl filters etc...

So has anyone considered a media ratio for pure ammonia removal..

Obviously a deal less than 25L / Fush... but what would be considered safe.. eg. 10L / Fush..
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The equations are fairly well known from the aquaculture industry. You need to determine what bio-media you will use, whether it be K1, bio-balls, beads etc etc so you know what surface area you will have. Then use the below formula to determine the feed rate/quantity in which it can process.

Surface area (square metre) x 0.6 / protein (%) / 0.092 = Feed input (g)

Theres some other things to take into consideration like solids removal, DO, temps etc but thats the basic formula.

per day?

Yep

Actually its not per day its per time period.

Its quite common for the time period to be a day but there are benefits to making the time period shorter.

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So you have to identify the fish type and numbers to give a recommended feed rate with its FCR ETCetc..

Hmmm.. as GG knows, the brain tends to spin with convoluted maths these days..

I'll lay off the red for a few days and give it a go..

Again, this is assuming COMPLETE solids removal via two swirl filters and a canister pool filter then to various media devices.. eg. Tall canister stuffed with layers of bird netting, Bio balls and. Similar..
Was thinking of adding a tube of clay balls..

I want a closed system that will avoid the possibility of a contaminant being dropped in. "Accidentally"
Like as appears with my current system - the death machine..
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You either have to do the math, copy someone elses that works or over engineer it.

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and in all honesty - that is likely the choice.. Just add MORE and MORE..

No one has jumped out saying.. " and for my 532 trout I have ---- and --- and --- "

probably I will go with new 100L of clay (so I know it is not contaminated), and then various plastic media.. like the scrunched bird-netting and layers of Bio-Balls..

The reality will be the given space, so I'm thinking to just "Fill That Space" with bio-filtering..

Reality - will be the available space for the fush.. that is the biggest limitation, so I really won't be able to go stupid with fish numbers..

Everything may change now that I have noticed a crack in the HDPE bin that I was to use for the main tank... Grrrr.. wonder if SEARCH will find a reliable repair for HDPE (garbage bins)
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Just make sure you put up lots of pictures so we can see your system coming together!

With toes

There has been a distinct lack of toes around here lately. I don't think the newer people know that tradition very well.

So you can't do the Chinese advertising thing and take a close up of a small system and make it sound BIG
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Pushin ahead... welded up the crack in the Wheely-Bin (industrial) - so gathering the necessaries for a fully off-line system..
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hmmmmm, is that formula for the max feed rate if you remove essentially all solids? Seems like it gives a rather low rate, unless it is per hour, rather than per day!

My old system (with NO solids removal), according to that formula, can only process just under 200g of 45% trout feed per day IF I removed the solids... but clearly it can process more than that without removing solids, so what's going on?

The formula suggests my new system, where I do remove most of the solids, can only process 130g of feed per day, but it appears to be capable of more than twice that so far. It has 3m^3 of a mix of coarse and fine gravel, conseratively SSA=300m^2/m^3, and I've been feeding in the range of 200-400g/day lately...which is probably fairly close to its limit at this stage for the existing bacterial population, as NO2 has been in the ~0.25ppm range a bit, falling if I feed less, and getting to near 0.5 a few times when I feed more. I might have to put some high SSA material in the ST- chopped corrugated 25mm HDPE is what I have in mind, as I increase feeding rates.

I feel so at home here