Fish Poo

[Tim Denford]

Hi I am very new as of tonight! I have a 1000 ltr tank with 60 fingerlings in it. My question is: Do I have to do anything about the poo/left over food, in the bottom of the tank? Or doesn't it matter?

Thanx in advance

[Keith Rowan]

how are you pumping water out of the tank to your growbeds?

you should be using a SLO (solids lifting overflow) that draws water from the bottom of the tank.. too much "gunk" in the bottom of the ft can cuase problems for the fish

how is the water flowing? if you can, use a centripedal flow and drain from the center..

[Tim Denford]

Hi Keith,

Thanx for the quick reply. I followed the Murry Hallam video so my water out is just by gravity from the corner of the tank to my sump. Can you please explain the solids lifting overflow and the centripedal flow method a bit more as I am not familiar with these.

Cheers 

[Keith Rowan]

ok, from your description, you have an IBC (the corner gave it away).

how big is the drain line?  add a short length, then a T (the top of the tee will be the "overflow", put a pipe towards the bottom, to another 90 to the center of the tank.. cover the end with a drain grate or screen, add some slots to the horizontal pipe..

direct the drain towards one corner of your ft.. i use an airstone in 2 corners so there is no solids buildup there

if your pump is oversized, add a diverter from your supply line back into the ft, and point the flow so that it goes in the same general direction as your drain into the ft - to create a swirl affect

[Tim Denford]

Hi Keith,

Sorry I was away for a week. I actually have the set up you described, but not the swirling effect. Then I had a brilliant thought! I have a 2 inch aquarium siphon that is about 15 inches long and I gaff tapped it to a broom pole making sure that the siphon was a little longer than the broom.

It took just 15 mins to siphon out ALL the waste into a bucket and when it settled I tipped the water back into the ft but left the sediment.  I tipped the last bit of water + waste onto my growbeds and the plants love it. This is an unreal idea and I think others should know if they don't have a means of extracting waste.

Cheers

Tim

[Jerry Nissen]

Great!  Can you describe a SLO for us?  I am currently putting together a system with 150 gal fish tank... plan to gravity feed..... Would truly appreciate your advice.... Many thanks... Jerry

Keith Rowan said:

how are you pumping water out of the tank to your growbeds?

you should be using a SLO (solids lifting overflow) that draws water from the bottom of the tank.. too much "gunk" in the bottom of the ft can cuase problems for the fish

how is the water flowing? if you can, use a centripedal flow and drain from the center..

[Keith Rowan]

TClynx has lots of diagrams of SLO's, (solids lifting overflow)..

http://backyardaquaponics.com/forum/viewtopic.php?f=11&t=5311

[virtualproto]

Compost the leftover stuff with worms.  They love that stuff.

This is a good PDF (PDF link on page) I found about that:  http://aqua.wisc.edu/publications/ProductDetails.aspx?productID=588