At level 95+, you get a 6x multiplier on your essence for water runes. At level 114, you get a 7x multiplier on your essence for water runes.
At 518 runes made, we can calculate you had 74 essence.
If you use the anima stone, you will be using 73 essence, but add 2 to the multiplier.
This means you can expect 73 x 9 = 657 runes. This is approximately what you received.
Please note that there is a small chance of obtaining more runes than the multipliers at each level, so the calculations may not be 100% correct. However, it does give the correct ball-park result, and you should not be expecting over 1k runes per run.
~A~
10-Nov-2022 23:41:26