To find out how much water Mackenzie poured into the pool, we need to add the two amounts together: \(7 \frac{3}{10}\) buckets and \(\frac{6}{10}\) of a bucket.
First, we can convert \(7 \frac{3}{10}\) into an improper fraction:
\[ 7 \frac{3}{10} = \frac{7 \times 10 + 3}{10} = \frac{70 + 3}{10} = \frac{73}{10} \]
Next, we need to add \(\frac{6}{10}\) to \(\frac{73}{10}\).
Since both fractions have the same denominator, we can simply add the numerators:
\[ \frac{73}{10} + \frac{6}{10} = \frac{73 + 6}{10} = \frac{79}{10} \]
Now, we convert \(\frac{79}{10}\) back to a mixed number:
\[ \frac{79}{10} = 7 \frac{9}{10} \]
Thus, the total amount of water Mackenzie poured into the pool is:
\[ \boxed{7 \frac{9}{10}} \text{ buckets} \]