I've been keeping two tropical frewshwater tanks now for three years as an introduction to the hobby. Both are about 40 to 50 litres. My newest and the reason for starting this hobby is a 130 litre marine tanks which I hope to stock with sea horses. At the moment it has been running for about two months since I added live rock (3.5kg). Just added two red Bali sea stars. One three weeks and the other a week ago. Looking forward to adding the seahorses in about another couple of months. All things going well.