I must disagree with you vox i have seen at least 3 additions which was not present in tekkit-lite, That is the dusts, an aludel the return of the alchemical chest and alchemical bag.
i think its a bug as it did it to me the only way i got round this was to basically empty the buckets in a hole and use a pump also i had to break a few tanks and put them down again before it finally filled them