A ANGEL FISH

Perfect—adding that **Chinese medium‑size filter** to your 300‑liter tank will make a huge difference. Even a basic filter provides two critical benefits your air stone alone couldn’t: - **Mechanical filtration**: It traps fine particles (uneaten food, fish waste, stirred‑up debris) so the water clears faster. - **Biological filtration**: The filter media grows beneficial bacteria that break down ammonia and nitrite, keeping water safe for angelfish, mollies, and guppies. --- ## 🌊 What to Expect - Within **24–48 hours**, you should see the water start to clear as particles get trapped. - Full clarity may take a few days, especially if tannins from wood are present. - Don’t rinse the filter media too often—let bacteria colonize it. Just swish gently in old tank water during maintenance. --- ## 🛠 Tips for Best Results - Keep the filter running continuously—don’t switch it off at night. - Combine with **smaller, regular water changes** (20–30%) instead of huge 80% changes. - Add **live plants** if possible—they’ll help stabilize water and provide natural filtration. - Feed lightly until the water clears, so waste doesn’t build up again. --- Your 200‑liter tank stays clear because it has fewer fish and less waste. With the filter in the 300‑liter tank, you’ll finally balance the heavier bioload of angelfish and guppies. 👉 If you want, I can give you a **step‑by‑step routine** for maintaining both tanks—feeding, water changes, and filter care—so they stay clear and healthy long‑term. Would you like me to lay that out?