Repeating fields or blocks

[pudgyb]

Is there any way to create fields, or multiple fields grouped, which have 0-* instances?

e.g., I have a record in which I need to allow any number of datapoints - a river is measured throughout the day and both the minimum and maximum heights need to be recorded and added to a report that spans a month. This means the report needs 28-31 pairs of values and timestamps (4 total fields per line) and I want this data to be added to a custom form

Is this achievable without creating a separate entity type and making 28-31 extra pieces of data for each record?

[victor]

pudgyb,

You probably have a diagram, scheme, table, or screenshots of how this already works or should work. Please provide additional information like this.