Fast-drying ink sounds convenient until the line starts skipping, the nib feels scratchy, or the pen dries out between sentences. Before buying a different bottle, find out which part of the writing setup is actually responsible.
Paper is the first suspect
Absorbent paper pulls water into the fibres quickly. That reduces smearing but can make a fine line look pale and a wet ink lose its shading. Write the same sentence on your normal notebook and on fountain-pen-friendly paper. If the difference is large, the bottle may be fine.
Then check nib and flow
A fine or extra-fine nib lays down less ink than a broad, wet nib. A dry nib can make any ink appear to dry immediately. Test a short line with a slightly wetter pen before changing the ink.
If the nib skips or stops, use the troubleshooting order in Why Your Fountain Pen Ink Keeps Stopping. Do not bend the tines to increase flow unless a trained repairer has checked the pen.
Climate and cap position matter
Warm, dry air changes the writing experience. An uncapped pen also loses water at the nib. Pilot’s official iroshizuku guide advises replacing the cap after use and storing ink away from direct sunlight and high heat.
Record the dry time on a normal page after the line stops looking glossy. The number is only useful when the paper, nib, ink volume, and room conditions stay comparable.
Choose the trade-off you need
If you turn pages quickly, a faster-drying setup may be worth a little less shading. If you journal on good paper, a slower ink may give you more color and a smoother feel. There is no best dry time outside a writing job.
The short answer
Test paper first, then nib and cap habits, then the ink. Changing bottles before isolating the variable turns a small setup problem into an unnecessary collection problem.