Backyard Aquaponics
A place to discuss aquaponics

Hi
A cheaper alternative is polystyrene beads with suitable nets. As used in bean bag chairs.
Maths was never that much fun when I was a kid.

..
..only issue.. they float... really float..
..
Floating will cause the beads to dramatically compact, restricting water ingress..

That would.seem to make them a.poor choice IMHO

Now the one.exception.would be if you contained.them within a vertical.tube, and pumped.from the top down, but even then I would think the top layer would act like a.filter.and.block up with muck..
..
Just suspicious that it would have real problems, and.to quote an oft' used comment.. ".. if it was such. A good idea, it would be common.practice now.."
.

wow guys , i totally botched that
its "1 lb (.5 kg) of fish for every 1 sq ft (.1 sq m)of grow bed surface area"
so all those numbers are off by factor of 100, so its:
10 lbs of fish
50 gallons of water for fish, rounded up from 30g


1)so a 10gallon pail 40%full of K1 ????
2)how do you guys feel about those numbers??

as for media type the general conscientious is to stick with the K1, and iv never farmed in life so i will trust!! I read that the K1 gains SA by the rippled edges, personally I would prefer best quality over lower price, especially if I only need what 4 gallons of it, my goal is smallest space possible, But what would be better than K1?

I wonder even more now that there are additional factors such as mentioned usable surface areas 3)any chance we know what the usable parts are?? , i have netfab 3D cad software that calculates those things, but im not sure how accurate it is, even if i were to consider it all useable...

Actually i was doing study in fuel cells , they used the wire brush said it had the best rates of consumption activity due to SA, but never compared it to K1.
maybe this is something i should test, but is it food safe????!!!!!!:.... also they dont mention surface area otherwise i would take that leap and try this out.... ....I would even hook the brushes to motor to spin them for a dual agitation effect with bubbles!
http://www.ebay.com/itm/60cm-Stainless- ... 2057962056

I am very afraid of unfood safe consumption by my clientele....


Also this confuses me again, at columbia water garden:
http://www.columbiawatergardens.com/Kal ... /k125l.htm

so the add says i get this airpump which i agree with:
Total Biological Media litres RecommendedAirpump
50-75 Airpump 70


but then it goes on to say this:
Media K1 K3
Total Surface Area 800M2 584M2
Total Protected Surface 500M2 500M2

so PSA is the same, but there is less TSA, isnt that better, whatever i will stick with k1!

Thanks guys for straightening up some of my confusions there, its just still hard to believe hot wheel tires are the best!!

I have never heard of filling the filter 40%. What I have heard for a moving bed filter is 60% media.

It seems a 40% - 60% fill for K1 media is pretty common. There are a lot of variables like water flow and air flow and also the bioload you filter. Some of the Koi folks go by that 40% number, at least as a starting point.

Designing a Koi Pond Biofilter / Bioreactor -- Biofilm requirements


I've seen other advice on how much K1 media one needs, suggest watching the media to see if it is too little or too much:

Steps in Calculating Amount of K1 in MB


I haven't found a local source of K1 media and don't have NEAR enough bottle caps saved up to make my MBBF yet, but it would be interesting to hear from those who are using one how they determined (or guessed?) the amount to use.

--
Sam

as far as i have been reading, that is all based on the SA,

a guy on youtube was very helpful with understanding some of the numbers, i believe it was him who said:
25sqft bsa per pound of fish
which is why we need to know the sa/v of a material,

with that we can plug in:

(25 * (pounds of fish)) = (sa required)
(25 * (pounds of fish))/(sa per vol of medium) = volume of media required


Also good idea about watching the color

This study used oyster shell media in their BAF (Biological Aerated Filters):

Study of municipal wastewater treatment with oyster shell as biological aerated filter medium

Another one for which it is a little easier to find the full text without buying it, from research perhaps (?) in Deuem's backyard, on the Fengtang Tidal River in the Guangdong Province of China:

Waste oyster shell as a kind of active filler to treat the combined wastewater at an estuary

They say, "The physical parameters of the oyster shells are as follows: true density 1275 kg/m³; bulk density 291 kg/m³; porosity 77 %; specific surface area 1210 m²/³3." That sounds like better surface area than even the K1 micro media.

In this paper, some insight into desireable characteristics of media used in BAF's:

Impact of aeration conditions on the removal of low concentrations of nitrogen in a tertiary partially aerated biological filter

Lot's of good research out there about biofilter design and operation...

--
Sam

OK, so first off the 40% or 60% numbers, either works just fine so long as you can keep the media rolling and aerated. When the media is new most of it won't roll and you just have to keep aerating until a biofilm develops and the media sinks to where it can roll. It helps to periodically push it down so that the ones on top have a chance to develop biofilm. Once the media is working well you can add quite a bit more to your filter.

On the Feed -
10 lbs X 0.02 (which is 2% feed rate) = lbs Feed per day = 0.2lbs
lbs to gms ---> 0.2lbs = 90.7 gms
From the Internet we know that 50L of K1 can handle 250gms of feed per day (based on Evol. Aqua's numbers) so we set up a ratio

X/90.7 = 50/250 and now we solve for X

X = (50 x 90.7)/250 = 18.14L of K1

I calculated this out another way and came up with 11.4 Liters of media which was supposed to be including fudge factor giving an excess of filtration. 4 gallons is 40% of the 10 gallon pail. Roughly 3.8 L to the gallon (US) so 15.2 L of media is what you'd have at 40% fill.

Basically I can't be sure you have enough media in the 10 gallon bucket . This would probably be more of an issue as the fish got larger although small fish eat more in proportion to their body weight. Of course if you were feeding at a lower rate like 1% as you reached the 10lb mark it would be enough. My natural tendency though is to want to double the amount of media - just because the media can filter the amount doesn't mean it will .

Hopefully I got this right and it helps but it's only an estimate.

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waste oyster shell would affect the pH so might not be the best choice for an AP system.

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Dr. Dodgy, I don't quite understand how this statement fit in . I understand that you'd want to keep things safe but the filtration used in AP is mainly to protect the fish from high ammonia and nitrite readings and provide nitrates for the plants, not so much to protect the people eating the produce (although it probably does help). You still need to clean the produce, just like you would anything coming out of a soil garden.

thanks usually do the rounding up while purchasing~
actually im going for a 208L barrel and 50 for the k1 (it was the latter of 2 selections)
as for this:
I am very afraid of unfood safe consumption by my clientele....
Mearly i was just mentioning again that I am after quality over efficiency today...

I am just leery since when i have been calling around to vendors, I ask if its food safe(filters specifically) , and they then hang up on me....
Now Idk too much about this, I understand that I need food grade material to build this, if i dont the unsafe plastic will "leach" into the water and causes toxic effects on humans, I am just going to assume that if this is the case it prolly cant be best for the fish... also maybe i need to worry that we eat plants that absorb toxins??
.....part of me wonders if its the same red tape as organic, where even though you grow organic, you cannot call it that without the license behind it...


Also what do you guys recommend for agitation of biotank, specifically the output point, rite now i am thinking i should get an air stone disk, or maybe several for each tank?

I have been getting in to air systems now, not only that but i have run in to gravity problem, so i will need several more pump points(up to 3), since i need to get air pump anyway, I wonder about using a Geyser Pump, considering i need to bubble air in and move water, are these powerful enough to replace water pump and does it compare in efficiency? I have seen threads looking down on these , but I wonder if they are efficient enough. Then again I could be wrong about all this, and the geyser pump at walmart isnt really even a geyser pump.... and that is just a brand name..

I'm not an expert but my understanding at this time is that most of these k1 like media are made from Polyethylene which is considered to be very stable and about as safe as plastics get (provided the material is not recycled). Ask if the media is made from virgin PE. If it makes you feel any better most of the plastic surface will be covered with bacteria.

I mostly agree, but I'm not even sure virgin vs recycled means anything any more except possibly for medical/lab equipment: "Recycling technology has been playing catch up but now it’s possible to achieve sorting purity levels of 99.9% from fractions as small as 1mm."

Interesting in any event:
"Sensor-based technology is also capable of detecting different types of PE and one application where this capability is being exploited is the separation of food and non-food packaging. Most non-food PE is coloured (shampoo bottles and detergents, for example), but in some countries natural or clear PE is now being used for non-food packaging. It is virtually impossible for the human eye to distinguish between the food and non-food PE but sensor-based sorting makes this distinction possible."

https://waste-management-world.com/a/tackling-complex-plastic-recycling-challenges

That's pretty neat. They tell me here that they can't accept used Polyethylene buckets but they can take milk jugs and other polyethylene. Makes me wonder what that's about. Seems likely the technology will take a while to get out to everyone.

as far as recycling goes i have been told that the milk jugs and such are class1, where they can be recycled , but after the process they are then type2 which cannot be used for food, i forget if they get recycled to class3, tires or similar, though.... not sure of the details and my info could be obsolete...

actually i was wondering more about these wire brushes:
http://www.alibaba.com/product-detail/A ... 87588.html


this is the type of item that the vendor wont promise food safety....and where i worry....

.....also I hope i don't need to worry about lead in it....

but I bet it has lots of BSA!

While I personally have no experience with such wire brush filter, I would assume there is a lot of surface area. As for food safeness no clue. But here is a question for yourself: how much gunk/bacteria etc. will build up on it? How much cleaning do you want to do?

A moving bed biofilter is self cleaning due to the movement of the media.

http://biofilters.com/ this website has some good information.

http://www.fishfarmsupply.ca/mm5/mercha ... ilterMedia

http://pentairaes.com/sweetwater-swx-bio-media.htm

with the last two websites you can see other media on the market.

I see what you are saying there, about cleaning with other options, so far its K1!

but this brings up another good question about agitation, I have seen 10$ bubble pucks at the pet store, or would it be enough to drop a tube with random mm holes in it?

I wonder if putting the brushes on a small motor and having them spin a bit would be enough to shake them off?

check out the tesla turbine!