So I need a bit of advice, i fully cycled my tank 2-3 months ago and added cardinals and a betta. No issues with ammonia or nitrite.
I went on holiday for a week used a tetra feeding block, I've now come back and my ammonia is at 1pmm every day even after a water change and nitrite is at 0.5-1pmm.
Im currently doing 90% WC's everyday.
Something has nuked my bacteria and i have no idea what.
I run a 30L tank no live plants, PH is 7.5, filter is running fine and temp is between 25-28degrees. Im using aqua safe everytime i do WC's and i now also add aquarium salt.