Hi everyone, Very new to marines (6 months) and have a small tank that was converted to marine before I bought it. Now long story short time, it was on a cartridge filter but I've made a sump and it was only when talking to George at Reefloat that he said I will be needing an overflow box (which I haven't got or even knew about). I must give a big thank you to George, I phoned to to buy a top up unit from him and he said he wouldn't sell me one just yet as I needed to sort out the overflow box etc, saving me on a very costly and major headache down the line....thank you for being a true gent and not grabbing the cash like most. Now at his suggestion, I would like to ask you all which boxes are to be considered as I said I'm new and would appreciate everyone's help on what one to buy. Tank is 120lt, 2 fish 2 snails 2 crabs, Kenya trees! I'm starting out very simple so I can learn before jumping into the big pool so to say. Thanks for the help guys and all opinions on equipment are appreciated. Rod.