Hi bro James72.
I have just started a new tank which most of the things are DIY except the tank.
In this setup, I'm using drop-in coil instead of chiller.
Titanium coil + air con spare parts ( copper pipe, etc )
--> You can get from Teck Hoe at Jalan Geylang ( one of the cheapest i can find )
For the controller
--> From Sim Lim Tower ( basement shop )
For the air con installation
--> I do my own piping and trunking, plus topping up my own refrigerant gas.