Boo hoo! Another problem and I'mreally trying my best! fish in cycle, going 6 weeks. 340 litres. Water changes 30% twice weekly. Slowly added guppies, tetras, corys over the last few weeks. Nitrite 0, amnonia 0, nitrate 1-2, PH 7.5 . stupidly got 6 rummy nose and added them at weekend, since...