Gazza
Brief description of this set up.
TOTAL GALLONAGE INCLUDING VORTEX = 525 GALL/
Vortex holds 75 gall on it own.
2" bottom drain with aerated spindrifter(fed with a Secoh 40 ltre) situated at front in the middle comes to 2" pipework.
2" pipe work T's off to drain via ball Vv, and also runs down the left hand side of tank through an isolating ball Vv to what is now a 14000 drymount aquamax (fitted after destroying 4 x 12000 eco aquamax).
From the pump, feeds into the vortex into a slotted spraybar, approx 2/3s the way up.
Overflows from the vortex through 4" pipe and 2 rubber elbows into the top of the homemade bakki.
The first tray you can see in the phots, the last tray is toppers with alfagrog, the middle 2 trays are a secret

(but work brilliant), secrets can be brought with beer

(all I can say is
:- IMHO, it works as well as bhm)
I think the rest is self explanatory.
I have just put some tell tale holes on the trays to let me know if they start clogging up with cress again.
There are 4 koi in there at the moment which I have grown on from 6-8".
The koi went in end of may last year at 6-8", and were shown at the end of may this year at the top end of size 4, with fairly predicable results.(bearing in mind (which is another secret--ooooh goody, more beer!)the object of that particular exercise)
The 2 Danitchi kohakus are certainly over 60 cm now, but I will not be netting them until April next year.
Of the 2 Showas, 1 is ok, the other has turned into a nice fish, but not a showpiece. Anybody want it?(for a very, very small fee?)(I haven't got room for it in the main pond).
So, anyways, there we go, any questions? fire away!
P.s I have got some k1 and k3 to put in the vortex but I need to work a couple of things out 1st.
Oh yeah, the contents of the vortex can be dumped straight down the drain when required.
PPS. Forgot, the tank is insulated from the ground by breeze blocks and polystrene sheet, which then lifted the tank of the floor and enabled me to fit the bottom drain.