I've seen a couple other threads on specific plants dying, but my problem is more general, none of my plants seem to last more than a few months. I have an Aqua One UFO 550 (88 litres), 2 x PL11W mix Triphosphor 7.1k & Biolux 8k Tubes. Fish; 5 x neon’s, 1 x red spotted guppie, 1 x zebra dino, 2...