Backyard Aquaponics
A place to discuss aquaponics

Made one today.
I found this black thing on a building site - I think its a sump for underground pipe works as it had 3 large holes in the bottom. Its kinda conical and the water is spinning nicely.

looking good jayendra
i know photos can be deceptive. how many litres of water is going through the filter?
cheers b&v

The barrel is 200 litres.

The system is 1800 approx litres

sorry my bad
i ment liters per hour being pumped into the filter
cheers b

resun byap pump, timed 45/15
loads of crap on the bottom already

I'm thinking of making a RFF from a 120L (or maybe even 80L) food grade wheelie bin. I found a post on a koi forum from someone that had found the weld at the bottom of the wheelie bin split after storing water in it long term.

Has anyone else ever had this problem?

Also, will the squarish shape of the bin cause any problems for the RFF dynamics (will use a 3000L/hour pump on a 2x500L GB system). I want to use a wheelie bin rather than a 200L blue barrel as it has a smaller foot print, and also a much smaller area at the bottom which I'm hoping will make drawing off the solids easier.

Also has anyone tried using uniseals on wheelie bins? Are they thick enough to enable a good seal with a uniseal?

Cheers
Matt

With 3Kl/hr or less why not go with a water bottle like icemandude? Or even a 60l bin? maybe the water bottle would be a little too small.

I run 8Kl/hr and use a 200-250l black barrel, water movement through that seems pretty fast.
it is tapered and the flat part at the bottom still collected heaps of crap, the tapering made no difference at all.

Uniseals should work perfectly.

Good to find a filter loving thread LOL

I asked about the square totes too and the concensus was it should be fine. I plan on building mine in the next week or two.

Uniseals no problems but they do split when water is store for awhile. My old bin I was using to drown weeds split about half way up, noticed the bulging and should have put straps around it to see if that would have prevented it.

Been using a 240 litre blue plastic drum for 4 years now and no problems.

What do you mean "square totes"?
do you mean IBC?
we are talking garbage bins with wheels, i dont think you guys use them over there much?

The ones I was asking about were these: http://www.shopping.com/contico-32gallo ... /info?sb=1
But any square container would have the same dynamics. Since all the "action" of the filter is inside the direction changing/settling pipe it doesn't really matter what the shape of the outer container is.

From the surface loading rates and retention times discussed by Earthan Group (He stated 120 to 200 LPM per M2 and retention times of 30 secs to 4 mins), it looks like 60L may be pushing it -

my calcs using a max surface loading figure of 200LPM per M2 on a 60L drum with 40cm diameter gave a figure of 1500L/Hour. With a 3000LPH pump I'd probably be closer to 2000LPH. The retention time was OK though at 2.4 mins.

It appears from these calcs that a wider diameter vessel helps keep the surface loading down. From a white paper I found (http://integrated-aqua.com/wordpress/wp ... epaper.pdf) this also stated that the inner diameter of the turbulence baffle should be a minimum of 25% of the overall drum diameter and the baffle should be well above the level of the sludge accumulation. It used a surface loading in its filter of 186 LPM/M2.

This analysis is probably way over the top for a simple backyard setup, expecially when you look at the fish stocking and feeding rates discussed in the white paper!!! That said I'm an engineer by profession so find it all interesting.

I've not got exact internal dimensions for an 80L wheelie bin, though they look about 30cm by 50cm (at the top) giving 0.15m2 which would give a flow rate of 200 LPM/M2 x .15M2 = 30LPM or 1800LPH and a retention time of 80L/30LPM = 2.6 mins. So the 80L wheelie bin is a bit better than the 60L drum. The height of the wheelie bin is handy as it means I don't need to make much of a stand to get it up higher than the GBs.

Its always good to know figures even if we dont stick 100% to them.
However the thing i fear with those figures is what you alluded to, make the container wider to placate one figure, it can throw the other out.
Or alternatively, you can have one in perfect ratio while the other is totally out.
Or you could simply give people the wrong impression when they dont know, and may end up thinking that surface loading is the most important over retention and end up using a container wider than it is deep.


How might you stop the splitting issue?

All wheelie bins are not created equal. A quick look at the local retailer tells me that the weld coming apart probably had a lot to do with the quality of the wheelie bin. Get the ones with the thicker plastic, they have less flex, I used one to store water (to irrigate seedlings in a greenhouse) for several years without incident.