Pretty sure that the calcium phosphorous ration thing is pseudoscience - i.e it's something that sounds plausable, but for which there is no evidence. Persistent infections, dehydration or hormonal problems are more likely.
That doesn't mean that I don't think that this is a healthy diet for guinea pigs - it's high in hay and a mix of vegetables and low in protein from pellets and calories which will result in a healthy piggie. And plenty of fluid. However I wouldn't syringe feed fluid to a guinea pig capable of drinking for itself because of the stress and risk of aspiration (the water going into the lungs and causing pneumonia).
Personally I'd go for plenty of unlimited good quality hay, lots of different vegetables fed regularly, limited high quality pellets and fresh water constantly available. Add plenty of exercise and you have a healthy piggie.
Paula