I have a fluval flex 34l tank and it’s been established for a couple of months. I have 5 minnows a fighter 2 hill stream loaches 2 rabbit snails who have had babies. I’ve come back to find the water is cloudy. I’ve just done a big water change but have checked various sites and that seems to be completely the wrong thing to do! I do 20% water change twice a week but want to go to once a week shortly and I check the water with test strips as well. I understand it’s a biological bloom. What’s the best way to go on this issue please experienced fish keepers!!