Assicurazioni Generali, S.P.A., et al., Respondents, vs. AMPA, Inc., d/b/a Y'All Come Back Saloon, et al., Appellants, Daniel K. Brennenstuhl, Defendant.

may not be cited except as provided by

Minn. Stat. § 480 A. 08, subd. 3 (1998).

 STATE OF MINNESOTA

 IN COURT OF APPEALS

 C8-98-1898

State of Minnesota,

Respondent,

Cynthia Gordon,

Respondent,

vs.

Rocklyn Weege,

Appellant.

 Filed May 11, 1999

 Reversed and remanded; motions denied

 Amundson, Judge

Hennepin County District Court

File No. PA10638

Amy Klobuchar, Hennepin County Attorney, Michael J. Gallagher, Assistant County Attorney, C-2300 Government Center, 300 South Sixth Street, Minneapolis, MN 55487 (for respondent State of Minnesota)

Cynthia Gordon, 8531 Girard Avenue South, Bloomington, MN 55420 (respondent pro se)

Christopher E. Brevik, 314 Brooklyn Crossing, 3300 Bass Lake Road, Brooklyn Center, MN 55429 (for appellant Rocklyn Weege)

Considered and decided by Crippen, Presiding Judge, Amundson, Judge, and Shumaker, Judge.

 U N P U B L I S H E D   O P I N I O N

 AMUNDSON, Judge

Appellant Rocklyn Weege (father) challenges the Administrative Law Judge's (ALJ's) calculation of his income and order that he repay respondent Cynthia Gordon (mother) back-support. We reverse and remand. We also deny mother's motion for attorney fees.

 FACTS

The 1982 adjudication of appellant as father of children born to mother reserved support. In 1998, respondent Hennepin County sought a determination of father's support obligation. In June, the ALJ found his net monthly income to be $1,055, set his prospective monthly support obligation at $347, and ordered him to reimburse respondent $8,088 for back-support. Appellant sought amended findings, noting guideline support for a $1,055 net monthly income was $316.50, and challenging the requirement that he pay back-support. In September, the ALJ stated the June order contained a typographical error and that father's net monthly income was actually $1,155, rejected his claim that he lacked the ability to pay back-support, and otherwise denied his motion. Father appeals. Mother did not file a brief on appeal and father moved to strike the county's appendix as containing matters outside the record, as well as an award of attorney fees.

 D E C I S I O N

When child support is originally reserved, a later motion to set support is treated "as an initial matter rather than a modification of a prior support order." Anderson v. Anderson, 470 N.W.2d 719, 721 (Minn. App. 1991). The traditional standard of review applies on appeal of an ALJ's rulings in a family law case. Lee v. Lee, 459 N.W.2d 365, 368-69 (Minn. App. 1990), review denied (Minn. Oct. 18, 1990); see Minn. Stat. § 518.5511, subd. 4(j) (1998) (ALJ's decision "is appealable to the court of appeals in the same manner as a decision of the district court"). Under that standard, findings of fact are not set aside unless clearly erroneous and legal issues are reviewed de novo. See Minn. R. Civ. P. 52.01 (findings of fact); Frost Benco Elec. Ass'n v. Minnesota Pub. Utils. Comm'n, 358 N.W.2d 639, 642 (Minn. 1984) (legal issues).

The amended order states the original order incorrectly found father's income to be $1,055 and that his net monthly income is really $1,155. Father alleges, and the county concedes, the original figure was correct.

Noting that the ALJ found the monthly expenses for father and his present wife to exceed his net monthly income, he alleges his support obligation is excessive. This court cannot make the factual findings required for a sub-guideline support award. See Minn. Stat. § 518.551, subd. 5(i) (1998) (guideline support is presumptively appropriate and any deviation therefrom must be supported by specific findings); Kucera v. Kucera, 275 Minn. 252, 254, 146 N.W.2d 181, 183 (1966) (stating "[i]t is not within the province of [appellate courts] to determine issues of fact on appeal"). Also, the ALJ did not separate father's expenses from those of the rest of his current household. See Lenz v. Wergin, 408 N.W.2d 873, 877-78 (Minn. App. 1987) (remanding support modification for reconsideration and directing district court "to exclude from consideration * * * that portion of [the obligor's] listed expenses attributable to his new spouse and her child"). We remand for the district court to find and consider the portion of the expenses of father's current household attributable to him for any necessary change in his support obligation, and for any findings required for the support obligation. See Minn. Stat. § 518.551, subd. 5(i) (addressing findings required for support determinations).[1]

Appellant argues the county, rather than mother, should be the recipient of any back-support. "[A custodian of a] dependant child not receiving public assistance as defined in section 256.741 has a cause of action for child support against the child's noncustodial parents" including a maximum of two years of back-support. Minn. Stat. § 256.87, subd. 5 (1998). Under Minn. Stat. § 256.741, subd. 1 (1998) "public assistance" includes medical assistance. Because this case involves public assistance in the form of medical assistance, we cannot say mother is entitled to back support.

Father also challenges the ALJ's finding of his income for purposes of back-support. A finding of net income for support purposes will be affirmed if it has a reasonable basis in fact. Strauch v. Strauch, 401 N.W.2d 444, 448 (Minn. App. 1987). The ALJ found father's net monthly income from March 1996 through February 1997 and from March 1997 through February 1998. While father did not object to the ALJ's use of wage-match information in the file, the ALJ did not specify how she adjusted the wage-match information for taxes or other considerations. See Minn. Stat. § 518.551, subd. 5(b) (1998) (listing deductions to be made from total monthly income to reach net monthly income for support purposes). On remand, the ALJ shall explicitly calculate father's net monthly income for purposes of back-support.

The appendix to the county's brief includes copies of father's statement of the case on appeal and a memorandum of the County Attorney's Office. Father moves to strike both documents and all references thereto in the county's brief, alleging neither document is part of the record on appeal. See Minn. R. Civ. App. P. 110.01 (defining record on appeal as papers filed in district court, exhibits, and transcripts of proceedings); Mitterhauser v. Mitterhauser, 399 N.W.2d 664, 667 (Minn. App. 1987) (stating any matters outside the record must be stricken). Because father's statement of the case is required to be filed with this court by rule 133.03, we decline to strike it. We also decline to strike the county's memorandum because it addresses the procedural posture of the case and does not impact our resolution of the appeal.

Father seeks an unspecified amount of attorney fees under unspecified authority for making the motion to strike. Father's motion is denied.

On remand, the ALJ shall have discretion regarding whether to reopen the record. This court expresses no opinion on how to resolve the remanded issues.

  Reversed and remanded; motions denied.

[1] A similar analysis addresses father's assertion that his obligation to pay back-support is defective because his expenses exceed his net monthly income.