hello everyone
i got some excellent advice from reefman when i posted the same query a while back
i bought a 250l jojo tank, i then reduced the height of the tank by cutting about 200mm of it and had the top portion welded backon, jojo did this for me. the opening on the top of the tank is big enough for a scoop net hence no modifications required. the tank holds abt 125 litres of water when 2/3rd full. the tank has a 50mm outlet at the bottom, this makes emptying the tank easy.
with respect to circulation i bought 2x 800ghp rule pumps and a 500 ghp pump, i have attached all the pumps on a stainless steel plate that i have mounted on the inside of the tank with two stainless steel bolts from the top, i also drilled a 20 mm hole on the top for the wiring, the bottom pump serves to pump water to an aerator which is mounted about 50mm above the water level, the middle pump serves to generate the current and has a filtration system attached to it made out of 50 mm plumbers pipe whilst the top pump also serves to generate a current however i have made a slight modification, i took a length of aerator tubing thats used in a fish tank filter and did the following with it
i squeezed the tubing into the mounting of the pump and positioned it at the centre of the pump, this is where there is the greatest suction, the other end of the pipe is outside the tank, when the pump is on the suction causes air to be sucked into the pump togather with the water and creates millions of tiny oxygen bubbles.
the wires are all attached to a rely box, my brother in law is an auto electrician he connected all the wires to a rely box that is attached to my dual battery system. the wires are all in heat shrink to make them waterproof.
once the lid is closed u have a problem getting air into the tank, to overcome this i drilled 2 x 20 mm holes on the top and inserted 2 pipes abt 30 cm long into the tank they have to be above the water level they stick out of the top of the tank abt 15 cms, this allows for the air flow and prevents the water from splashing out of the tank.
trust this helps
regards
grumpy