Usher & Tameka -- Battle Brewing Before Pool Accident

Usher and his ex-wife Tameka Raymond were on the brink of war BEFORE their son almost drowned in a pool ... and it was all over child support payments, TMZ has learned.

Usher filed legal docs earlier this month asking a judge to lower his child support payment to Tameka. As it stood, Usher was shelling out $8,000 / month for the couple's 2 sons ... which he claims is BS.

Here's why ... Usher says that child support amount is from an old agreement and hasn't been changed since he was granted PRIMARY custody last year. He says he's been overpaying the last 7 months and wants a judge to remedy the situation.

Usher requested a hearing on the matter -- but so far, no date has been set.