Distilled water is recommended.

Without dilution this developer will produce brown/black tones on papers in about 2 mins.
Diluted 1:2, this developer produces brown tones in 4-8mins.
Diluted 1:4, and developing for 8-15mins, produces a red/brown tone.
Diluting 1:6, and developing for 15-25mins, will produce a red tone.
For still warmer tones, add 10g of sodium bicarbonate to each litre of diluted developer.

Reproduced from The Darkroom Cookbook by Steve Anchell

See my less-than-perfect test of this developer on this page.