Julie A. Dahlberg, Obligee, County of Anoka, Respondent, vs. Todd P. Shafer, Appellant.

may not be cited except as provided by

Minn. Stat. sec. 480 A. 08, subd. 3 (1996).

 STATE OF MINNESOTA

 IN COURT OF APPEALS

 C4-97-1550

Julie A. Dahlberg, Obligee,

County of Anoka,

Respondent,

vs.

Todd P. Shafer,

Appellant.

 Filed February 24, 1998

 Reversed and remanded

 Harten, Judge

Anoka County District Court

File No. F4-97-5030

Peter J. Wolf, Shelly D. Rohr, Wolf & Rohr, P.A., 960 Norwest Tower, 55 East Fifth Street, St. Paul, MN 55101 (for appellant)

Hubert H. Humphrey, III, Attorney General, 14th Floor NCL Tower, 445 Minnesota Street, St. Paul, MN 55101 (for respondent)

Robert M. Johnson, Anoka County Attorney, Robert D. Goodell, Assistant County Attorney, Anoka County Government Center, 2100 Third Avenue, 7th Floor, Anoka, MN 55303 (for respondent)

Considered and decided by Short, Presiding Judge, Harten, Judge, and Mansur, Judge.**

Retired judge of the district court, serving as judge of the Minnesota Court of Appeals by appointment pursuant to Minn. Const. art. VI, § 10.

 U N P U B L I S H E D O P I N I O N

 HARTEN, Judge

Appellant Todd Shafer appeals an order that he reimburse respondent Anoka County for past public assistance paid to the mother of his children and that he pay ongoing child support. We reverse and remand.

 FACTS

In December 1996, Shafer's marriage to Julie Dahlberg (mother) was dissolved. The parties were granted joint physical and legal custody of their two minor children. Support for the children was to be divided equally.

Mother began receiving public assistance in February 1997. Anoka County thereafter brought this action against Shafer under Minn. Stat. § 256.87, subd. 1 (Supp. 1997) seeking (1) reimbursement for public assistance paid to mother, (2) ongoing child support payments, and (3) $100 a month in medical support.

A contested hearing was held before an administrative law judge (ALJ). Shafer and mother agreed that each of them had custody of the children approximately 50% of the time. The ALJ found that Shafer has a net monthly income of $1,029.79 and monthly expenses of $1,175, and that mother's net monthly income is $605, which is exceeded by her monthly expenses. The ALJ found that Shafer had the ability to reimburse the state $1,016.79 for public assistance that mother received from February through April. The ALJ also ordered that Shafer pay $308.94 per month in ongoing child support. The amounts of past reimbursement and ongoing support were determined according to the Minnesota Child Support Guidelines.

 D E C I S I O N

In an appeal from an ALJ's decision on child support, we apply an abuse of discretion standard of review, not the standard of review normally used when reviewing agency decisions. Lee v. Lee, 459 N.W.2d 365, 368-69 (Minn. App. 1990), review denied (Minn. Oct. 18, 1990).

The county is entitled to a judgment for past assistance "which the parent has had the ability to pay." Minn. Stat. § 256.87, subd. 1 (Supp. 1997). In addition to past reimbursement, the court may "order continuing support contributions by a parent found able to reimburse the county." Minn. Stat. § 256.87, subd. 1a (Supp. 1997). Ability to pay past assistance and ongoing support is determined according to chapter 518. Minn. Stat. § 256.87, subds. 1, 1a; see County of Nicollet v. Larson, 421 N.W.2d 717, 721 (Minn. 1988) (stating that "the legislature intended the amount of ongoing reimbursement be determined with an eye toward the guidelines") (footnote omitted); State ex rel. Miller v. Miller, 446 N.W.2d 199, 201 (Minn. App. 1989) (noting an amendment to Minn. Stat. § 257.87, subd. 1 "requires" consideration of chapter 518 and the guidelines in actions for reimbursement of past assistance).

The decision to order reimbursement is within the discretion of the district court. State ex rel. Region VIII North Welfare v. Evans, 402 N.W.2d 158, 161 (Minn. App. 1987). It is in the public interest for a parent to reimburse the county for public assistance when the parent has the ability to do so. County of Nicollet v. Larson, 421 N.W.2d 717, 720 (Minn. 1988). In cases of public assistance, a court may deviate downward from the guidelines it if finds "that the failure to deviate downward would impose an extreme hardship on the obligor." Minn. Stat. § 518.551, subd. 5(j) (Supp. 1997).

The ALJ ordered Shafer to pay the guidelines amount of ongoing support and past assistance. See Minn. Stat. § 518.551, subd. 5 (1996) (setting out child support guidelines). Shafer argues that this amount causes extreme hardship for him, because it leaves him with a monthly deficit of approximately $515. He also argues that because this is a joint custody situation, the ALJ should have applied the Valento formula for calculating support. The Valento method of calculation reduces the guideline support amount proportionally to the time that each parent has custody of the children. Valento v. Valento, 385 N.W.2d 860, 862 (Minn. App. 1986). The county concedes that it was within the discretion of the ALJ to apply Valento in this case.

Although the parties agreed at the hearing that Shafer had the children about 50% of the time and that he took care of their needs when they were with him, the ALJ's findings did not mention Valento or any consideration of Shafer's contribution. As a matter of fairness, implications of the joint custody arrangement should be addressed, with reference to Valento.

On remand, the ALJ has discretion whether to reopen the record. We express no opinion as to the proper amount of support.

  Reversed and remanded.