Salt and sugar are necessary in moderation. Salt and potassium are crucial for nerves to fire - there's a complicated mechanism that depends on these minerals. Sugar drives many of the processes that bodies need to keep functioning - respiration, moving oxygen, food and other stuff around the body and so on. Don't forget that our bodies go haywire if we have low blood sugar too. We should never seek to eliminate them from anyone's diet, not our own and not our birds'.
The problem is that, because they are so important and generally scarcer in nature, most animals have developed a real taste for salty, fatty and sugary food. We know these nutrient dense foods are valuable and so we seek them out. Given the choice, we'd much rather wolf down a plate of salty chips or a slice of cake rather than a plate of salad because in an ancient part of our brains, something is telling us that we'll get valuable calories and salts and sugars from this. In nature this wouldn't be a problem for us or our birds because access to these foods would be severely limited and we'd be spending considerable energy just finding them in the first place. Wild parrots fly miles each day in search of food and are very active. The problem comes in captivity where these foods are readily available and we (both humans and birds) can eat far too much of them. Our brains are telling us to eat as much of this valuable resource as we can, but we're largely too inactive and can eat far more sugar, salt and fat in one sitting than we need. I can easily purchase, prepare and consume 6000 calories in under an hour, but if I were foraging, hunting and scavenging, it would take me hours (maybe even days) to find, process and consume 6000 calories worth of food.
So, sugar, fat and salt are not bad by themselves. We run into major problems when we try to cut our sugar, salt and fat out of our diets completely. However, we do need to consume them in limited amounts. I hope that makes sense!
I would dilute the ORS - 50 per cent ORS, 50 per cent water - and only give it if he is not eating normally, is vomiting or has diarrhoea. If he is eating pellets, then he is getting salt from the pellets. Try to feed him a bit of banana for potassium..