I'm a newbie. 125g mixed aquarium, 150-170 lbs of LR and LS, my local LFS tests my water so I don't know the exact parameters (they say the water is good), t12 lighting, filtered tap water. Which is more important...to upgrade the water by purchasing an RO unit or updating the lights (my local LFS says the t12s are outdated and hard to find). Everything seems healthy. The fish eat well and are very active so I don't think there is any immediate danger.