I would assume to get added oxygen enrichment to the water along with the airstones.
But what I have found is that no airstone are really needed. Using extras parts I added to my rdwc ( pump for discharge).
Did flood-drain for a better part of a century and it definitely has a place for...
There are many ideas out there on the waterfall scene.
On my undercurrent setups I use 4 , 1/4 irrigation tubes to spray in each of my totes.
Using a valve or 3 with the drain pump , dual purposing it for suppling these sprays.
Then a good undercurrent pump pulling my flow through and back...
After roots made it to water it slowly got its colour and growth immediately started.
It bushed similar for a good two weeks on 18-6 then it finally has come out and staring to full veg again.
With rooting 6 weeks.
I use ro water that’s about 6 .
24ml in 5 gallon and that gives me 160ppm.
I would think your not too far off.
Now the 800 , if on the 500scale that’s 1.6ec.
That would be way to hot for my ladies taste.