Except as otherwise provided in this chapter or section 518A.53, the priority of multiple earnings garnishments shall be determined by the order in which the garnishment summonses were served on the employer. If the employer is served with two or more garnishment summonses at the same time on the same day, the garnishment summons issued pursuant to the first judgment entered has priority. If two or more garnishment summonses are served on the same day and are based on judgments entered on the same day or if there are two or more garnishment summonses based on prejudgment garnishment pursuant to section 571.93, then the employer shall select the priority of the earnings garnishments. However, in all cases except wage garnishments on judgments for child support if the judgment creditor is a county and the employer is notified by the county when the judgment is satisfied, garnishments shall be effective no longer than 90 days from the date of the service of the garnishment summons.