Hey, im new here. I already have a tank, but it didn't go very well, many species died, such as corals and fish. I think this was due to overpopulation, I put like 7 fishes (including tanks) in 100 liters. Now i know a lot more of reef and I want to make a shallow reef without sump and skimmer. Can you give me your best tips? So far I plan to do water changes every 2 weeks and nice flow. Help me with your best warnings, i want a really succesfull tank. And im planning only to keep: 2 clown fishes, 1 mandarin, soft corals and lps in 100x40x35 centimeters