Backyard Aquaponics
A place to discuss aquaponics

Anybody have an idea how large a filter of this type would be needed for a raft system that has 6000 liter FT and about a 10,000 liter raft tank?

Sketched up a rough filter setup like this using 2 55 gallon drums.... One as a separator and the other as an upwelling media tank... That plus the surface area of the raft tank... think it would be enough??

Thanks,

CB

I think you could test it out with a lower stocking rate to begin with, check the water often and if needed add another barrel of media before you up the stocking level.
I dont know much about raft systems, could you add extra media under the water level below the rafts?

Great Stuff! Ben,
I think this is exactly what I need for my vertical NFT system. The pipe thingy!

Knowmore
cool glad I could help, If you want any help / advice let me know mate.

some changes I would make if doing again,
1- put the tap through the floor and sit the filter on some bricks or something as sealing a tap into the curved side was a bitch and bottom would back flush better i think.
2- at the top where the water flows in I would put a 90 deg bend instead of the 45 i used as i think the pipes would be under less stress if the pipe hung straight down.

will try to remember anything else I dont like for ya!

The BYAP formula is a proven model. Simplicity is always best. However, there are many good reasons to filter including high production, limited space, limited budget, portability, ect ect..

Bio/mechanical filters have many benefits when added to an AP system. Cleaner water is always a plus. If I had the time and money I would have massive gravel beds in a heated green house, but I dont. I am raising plants and fish to feed a family 100%, not supplement veggies. So production is required in the indoor nursery system as well as the grow out area.

For me I will be housing and feeding 500 warm water fish over winter in 600 gallons of water. Solids removal has so many advantages when you start reaching higher stocking densities. It also gives you the chance to reduce oxygen demand with the option to quickly breaking down solids in a digester to release more nutrients for plants to use.

Some highlights of filters:
Clear Water.
Higher Do in water for fish health.
Increased stocking density.
Reduced system foot print.
NFT or DWC for reduced gravel handling (back breaking work), or portability.
Intensive planting and fruiting plants greatly benefit from digested waste.
A good filter is automated and does not require constant attention.
A good filter removes or digest solids from the system quickly.
Indoor fish wintering becomes possible.

Interesting tid-bits and observations:

PVC ribbon has a surface to volume ratio of 250:1

.0125 cubic feet of PVC ribbon per pound of fish is more than enough for bio filtering.

A digester with aerobic and anaerobic processes breaks down waste very fast.

Digesting waste releases nutrients so plants do not need as much supplementing.

Daily purges of filters and topping off water is enough to raise fish without plants.

Separating fish and plant production allows both to be optimized.

The more factors you have control over the more productive a system can be.

Much less bio filter is needed when pumped 24/7 vs once and hour

Many plants do better with fewer flood cycles.

At 19400 grams of fish(97fish) in 300 gallons of water ammonia is detectable with 30 minuet pump cycles, but a small continuously pumped bio filter keeps ammonia undetectable.

A combination of aerobic and anaerobic digestion does amazing things for plants.

Removing solids before the pump greatly increases system DO and water clarity.

Solids require worms in beds to break down at a decent speed or solids can be digested.

Continuous water movement through the fish tank keeps fish happy and healthy.

That will depend on the amount of fish in the system, the amount of extra aeration you provide, what media you use in the filters, and if you do anything extra to remove solids before the filters.

I'm guessing that a somewhat poorly done (as in no extra solids removal pre filter and only some extra aeration added to the filter) you might need say 400 gallons of pot scrubbie billed barrels. As soon as you improve the aeration and remove some solids before the bio-filters, you might be able to get away only two barrels.

Okay,

Let's see if I've learned anything from this thread....

I have just started using SketchUp, and it was pretty frustrating, but here are two drawings. One is just a two barrel filter system and the other is that system in a raft setup designed for small commercial lettuce and herb production.

I did not include air lines in the drawing, but in this plan I would have an air line running down the down tube so air is mixed with it at the lower 'tee' in both barrels.

The Commercial system is currently planned as two independent tank setups with 16 6' x 4' (72 plants) rafts rotating so 4 are harvested each week. This 20' x 80' GH would ideally produce about 600 plants every week....

A mod can copy this post to another thread as a system proposal to banter around if the system is to be discussed. Primarily here I'm asking if I understand and have the barrel filters set up about right....

Thx.

CB

Hmmmm.... Won't let me load .skp or .skb files. Anybody know what I did wrong?

Think you are supposed to save them as JPG files so they can be veiwed without having to load them into sketchup.

Ben,
yup! will do. the tap at the bottom will be very convenient since I will be hanging the pipe down. For filtration I am planning to use charcoal (well washed!!) and nylon scrubs in the upper chamber separated by a scotch brite pad at the base. What are these pvc strips Dan is referring to? Maybe I could bung in a few of those too. And also what kind of digester does one use in a system like this?

Thanks for the input.

export the sketchup files as a 2D file and then size it for the fourm

jT

Here they are as .jpgs.

If I'm reading you right... then your floating raft system is approx 64'x6'x1' (assuming a 1' depth)... => 384 cubic ft... a volume of 2872 gallons (10873L)...

Pumping back to a 6000L fish tank .... overflowing into 2 x 55gallon => 110gallons (416L) filters ... which upwell and overflow into the rafts...

And a similar second system, presumably flood & drain... of the same dimensions...

In terms of the flood & drain system, probably no problems... other than with a growbed capacity of 10000L... I'm not sure if you would need, or benefit from the solids removal by the barrels... without compromising nutrient and trace element delivery to the growbeds...

With regard to the "raft" system....

I'm not sure that 110 gallons of barrel filtration will be anywhere near sufficient ... in terms of bio-filtration.... or solids removal capacity...

And would probably require constant maintenance...

Particularly with the flow that you would require to turnover the tank volume once per hour... and/or supply the raft beds...

And that in itself raises a very important design consideration... would the overflow from the barrels be sufficient to supply enough flow rate and oxygenation to a raft bed of those dimensions... personally I doubt it...

Unless you're using some mothers of pumps to return water back from the raft bed to the fish tank... thus forcing high volume/flow turnover out of the fish tank...

If this was the case then, frankly I don't think, unless you ustilise really large pipes... that your barrels will be able to cope with the flow rate... particularly as they become clogged with "solids"...

I know that similar filter concepts utilising scotch pads... i.e the skippy filter are capable of supplying filtration to quite large volumes of water...

But at flow rates... and stocking levels way smaller than you probably envisgae or need... particularly to supply the raft bed...

If you're pumping back to the fish tank with enough capacity to supply oxygenation and flow rate to your raft bed... then even with large pipes... and you can only go so big inside the barrels...

Then you'd better be able to seal the top of the barrels... because they'll be either under pressure... or upwelling the pads over the top...

IMO... the barrels... just by sheer dimensions... wont be big enough to enable sufficient bio-filtration AND flow AND oxygenation to the raft bed...

Somewhere in this forum is a fellow who has a rectangle koi/goldfish pond in his backyard in Austrailia with a biofilter system that incorporated 2 IBC's. He was building grow beds to do away with the biofilter. I did a few searchs but couldn't find. The pond was the size of a small inground pool.