Passing urine 25 times a day certainly is not normal even with diluted feeds. This is called polyuria. Even though it could be partly due to frequent diluted feeds, there is a possibility that this could be due to diabetes mel litus, diabetes insipidus or a kidney disorder. It is possible to diagnose these by simple tests. This could explain why he is feeling hungry (probably thirsty as well - polydipsia) 40 minutes after every feed. To begin get a simple bioch emical examination of a fresh sample of urine for protein, sugar, ketones, specific gravity and osmolality. If there is an abnormality, he will need further investigations to confirm the diagnosis. If the above disorders are reasonably ruled out, you ca n attribute the polyuria to diluted feeds alone. You have some misconceptions about digestion too. A child with inability to digest will be passing stools many times a day than be constipated. The hard stools are probably because there is very little fibre in the diet and most water is a bsorbed from the intestine and excreted as urine. Feeding extra dilute feeds will not improve digestion. It will make the stools harder. There is no need to dilute cows milk except remove a bit of the cream layer for a 6 month old baby. You should try more semisolid foods throughout the day if he does not have one of the problems suggested above. Digestive syrups and tonics are likely to increase the polyuria due to the high sugar content in them. You are already giving a good amount of usual weaning foods to your baby. A good indication as to whether the food is sufficient is good weight gain which can beassessed from the growth chart. If he is slipping behind, there is something to worry and to investigate.