Backyard Aquaponics
A place to discuss aquaponics

Tim, mate, i just want you to hang around the college some more, thats all..
It is very good to see Robyns system going though

Its all good, I was only rubbing it in...

Two Problems & a Possible Solution
Before getting more fish, I would like to solve two problems.

Firstly, I would like to protect at least a reasonable quantity of water in the fish tank in case of “accident”. I naturally thought of raising the pump off the bottom of the tank, but …

The second problem exists now, with the pump on the bottom of the tank, and would be exacerbated by any raising of the pump. I have a 3000lph pump on the bottom of the ft which flows up to the gb. However, it does not seem to clean up detritus from the bottom of the tank. I think the cage protector around the inflow pipe is too broad – which because of its size reduces the “pulling power” of the water flowing into it.

Now I am really jealous of VB where “the fish poo is out of the tank in no time from when it leaves their bums”, but I cannot have a central drain as my tank is buried! So,

CHECK BELOW FOR DIAGRAM!

Now this looks a lot like Michael Ferrini’s (thanks Michael) but mine is directly connected to a pump, not gravity-draining, and as mine is not CHIFT-PIST, the volume in the ft varies by up to 300l due to flood and drain quantity.

Could this work and be a solution to both problems? In particular:

Query 1:
Has anyone directly connected a similar contraption to a pump, especially if that the pump works on a timer system? (If I remove the cage protector from the pump, it has a threaded male connection, so I assume that with the correct fittings, I can physically connect the pump to this type of drain system, but I am worried about enough water flowing into the 3000lph pump!)

Query 2:
Would the difference between the overflow level or outer pipe and the drain level or top of inner pipe (Level A and B in the diagram) affect how much detritus is expelled, especially when the water level is high?

Thanks, everyone – would love to hear comments and ideas as to how I could use/adapt the above to solve the problems mentioned.

Robyn, remove the bottom grill from the pump and check that there isn't a "filter" pad in there... if there is turf it.....

Cheers, Rupe, but no filter pad!

Thinking about it more....

If you can get the water swirling (ie. Moving in a circular motion) by using the excess from the pump. With the pump in the center you should be able to pickup most of it as it reaches the middle.

The cover for the pump does not have any holes underneath from memory, you could possibly take it off and drill some holes in it to help pick up some of it.

No matter how you do it, you will not be able to pickup sand or anything that has any real weight to it. All fish poo will break down over time and eventually disappear. Yabbies or Marron would speed that process up.

Or go for a nice big pleco, they don't stop cleaning the tanks and can cope with temps down to 18°C.
It won't eat all the stuff but scrape the bottom.
And your idea with a swirling current would make things better too.

Thanks, Amacafish - will look at pleco (TimC & NicholasC are quite into them, so I have learned a little about them!) but would like to get through one winter first to check what temps etc I get. As a newbie, I have no idea whether I can keep it at 18C.

Currently I have a pump creating a current, but with the pipe end near the surface to help with oxygen. Not sure whether this would create the current needed at the bottom of the tank. What do you think?

Plecos (sailfin gibbys) are around $35ea at 10cm and grow this big:


Imo i think they would be great to have in AP as long as the water can be mildly hot (around 20C +)

Nic

Put a fishing floater in the water, try it on the surface, see and put fishing weights on it (will not float as well!) and try again.
You'll see how the wter moves.
And for the water temp, check the registered air temps on the net for your place. The tank depending on its volume will aproach the air temps around it.
And I wouldn't go for any L's catfish, or maybe just them and small fish and sell them afterwards. But I suppose that Nic C won't like you eating any of his L's...

Just do what tim says robyn



..or we will talk more tomorrow about it at work.. ..wonder if those new vacuum cleaners work under water???

Common/sailfin Plecos still have a L number (L021/L023 and sailfin L-83)

The locals around the african lakes (though they are not native, introduced) eat them and someone had a picture on another forum of them all lined up at a fish market, quite disturbing!

People in QLD breed L001 (goldspot plecos) which fetch a bit over here (10cm $70+ea) in ponds with a mud bank on the side, this is why the thought of growing up plecos in close to no nitrate water (AP) would be quite rewarding.

Nic

Ps: more pictures Robyn

Pics soon, Nic - remember I am an old hard-working woman so nothing significant happens during the week - this week I have only cleaned the empty growbed, raked the area and leveled it, placed four slabs to stand the growbed on, placed and leveled the growbed, fixed most of the plumbing for the new growbed, laid some weedmat, purchased some river rocks to cover the weedmat, washed 4 bags of hydroton, (6 to go!) ... as well as some dirt gardening!

Just be careful with a pleco in a plastic tank. Their teeth are like rasps, and they can wear through plastics.

They wear through my rock! :-)