The ocean is such a huge place, that there is probably zero theronts in the water column anyway.
It may be fine to dump in straight away.
However after three weeks, I reckon I could guarantee Zero theronts.
The only way you are likely to get parasites directly while pumping are if you are near a fish swimming area.
And then if one or two fish swam by whilst you were pumping, what are the chances of them having a cyst that has just dropped off immediately as they swim by.
I have 500 litres storage containment uphill from my tank, so storage is no issue.
Stored water is better IMO.
I dont want plankton and other stuff which will more than likely die after 3 or 4 weeks.
Layton, this isnt an argument, some of us have valid reasons which should be obvious to you. However each to their own.
You must be able to see why some of us prefer this.