Dr. Scott pointed out again that calcium/phosphorus related problems are the most common ailments she sees. But simply feeding turtles a store-bought nutritional supplement isn't always the answer. Always read the back label of a supplement to check the calcium/phosphorus ratio. If the two minerals are perfectly balanced that's great if your turtle is `normal' - if it has no deficiencies. But since 90% of the animals Dr. Scott sees do have a calcium deficiency, adding equal amounts of calcium and phosphorus won't correct the imbalance. So read the label and choose a supplement with more calcium than phosphorus, or with calcium only and no phosphorus.