Backyard Aquaponics
A place to discuss aquaponics

Swed and cookie,

I have an extra ibc. Ha. Can I use this inline between my shade cloth filter tanks and fish tank to settle out the larger solids as I was trying to do with the clarifier? Heck. The ibc will have a retention time of about 45 min at full volume. Wheels are turning in my head. I'm all ears cookie. Off to google to search settling tanks.

yea you can but RFF filter will be your best bet.. as well as invest in a siphon to suck out solids from the base... and well its smooth sailing after that.

Coachchris, plain sugar I was told by Paul Van Der Werp as well as yeast. I have not used either yet. I would probably start with just sugar. Also,mind to use plenty of aeration as the bacterial growth will explode using up a lot of oxygen. If aeration isn't sufficient it will go anoxic or anaerobic

Thanks Swede. Sugar is a lot cheaper then molasses.lol I know most recipes for worm tea use molasses as a sucrose source.

Cookie,

Do you have a formula for what size of a offline MT is optimum for a given amount of system water of fish load/feed rate? Since I am going to use a RFF, might as well find room for a proper sized MT.

honestly no atm I don't have a formula for sizing.. but im using the same type of container I used as my RFF filter as my MT... if anaerobic digestion is done correctly.. solids shouldn't in theory accumulate due to losses as methane.. carbon dioxide.. acetic acid and ammonia..

Cookie,
Ok thanks I will start with a 55gal drum. As This is what my one of my RFFs will be (running dual)

So when and how often and how much sugar do I put in a 55 gall barrel?

Swedaquaponics,you mention in your post you would like to try the Cornell style dual drain system for solids removal,i have ran bottom drains and surface drain in my fish tanks now for a while very successfully,i thought i would post this out of interest for yourself.This is my airlift system bottom drain set up which works well at keeping the tank clean.
The bullhead fitting is a three inch with slots cut in the bottom face,these are 10mm wide and the width of the slot,cut into three of the faces of the nut,there is then a standpipe the depth of the water.In operation solids,fish feaces, migrate across the bottom of the tank and are removed through these slots,the important part being is they remain as one piece unless a fish decides it would like to try to eat it,by remaining in one piece it is effectively keeping the solids easier to remove and when it reaches the RFF again it is easier for a quick settlement.
In the Cornell culture tanks they are designed for stocking levels that we would never require for AP with the solids consisting of feaces and uneaten food,again something that is not such a problem in AP.
This is just my take on surface skimming plus bottom drain,it doesn’t mean that i have been able to reduce the size of my RFF,but by sizing it to a 2 minute retention time it seems to being working very efficiently,the system is 3700 litres with a 1500 lph turn over,the RFF is sized at 60 litters.

Hi dasboot,
I appreciate your input but I am not sure that what you have there is the same thing I am talking about. The bottom drain would only take out 5-20% of the total inflow. The rest would exit through the top side. The bottom drain is led to RFF which then doesn't see the total flow but just a fraction of it. So if total flow is 560gph then at 5% the flow would only be 28 gph. By having a much slower flow but still taking out say 80% of the solids the size of RFF can be downsized accordingly...
I am not seeing this in your setup or am I missing something?

Your absolutely right,i posted it just as an alternative approach to solids removal,i use the smallest barrel i can find at 60 litters,this gives me close to the ideal retention time of nearly 2 minutes.

The thing that we all seem to miss is that the test done between swirl settler and radial flow settler is that their design has a jagged weir all around the exit. Most of our designs doesn't have that but a single pipe that is the exit. This creates more turbulence in the RFF which more than likely allows more stuff to escape out of RFF. So maybe for a home made RFF we should aim for a little longer retention time than what is suggested. Just some thoughts..

LOOK what my work brought in today... Hach complete with all elements for our testing need for aquaponics.. OMG I'm in heaven.

Aahh.. Fantastic cookie. Looking forward to seeing some tests on your system,water.