The scientific method

Corpse size has a lot to do with it. I wouldn't swim in even a large pool with a dead human in it (knowingly), but one dead fish or rodent or dozens of dead tadpoles or bugs? Not an issue.

Heck, most household swimming pools have dozens of dead bodies in them, but they're 99% insects.

The whole premise of this meme is a bit silly. If there was a corpse floating near the beach, I think most people might wait for the corpse to be removed, and perhaps even a reasonable cause of death to be determined, before entering the local area. The same is true for pools.
- Ah, so corpse count AND proximity are both factors? Along with knowledge of the presence of said corpse?
Ah no, a dead fish indicates that the water isn't healthy. You should shy away from it.
- Yeah, fish always make sure to leave the water before they die.
Now what if it's a severed human head?
- Or a couple of severed toes or fingers?
- Hard no, leaking is gross.
What about a dead baby?
- Dead babies don't care how many bodies there are.

People will walk through a forest that definitely has many corpses in it. Humans will not walk through an alley that has 1 corpse in it.

Humans have a corpse: proximity ratio that they find acceptable.

Edit: typo

I'd call it a radius, not a ratio, but yep.
- If you knew there was a dead person next door you might be a little uncomfortable, but could go about your day. If you knew there were 50 dead people next door you would need to get out of there.
  The number is relevant, not just the proximity to the closest one.
- I'd also call it a corpse, not a course:
Some humans will go to a Japanese forest for the express purpose of live streaming a corpse.
- Ugh I hate that guy
How does graveyards fit into the equation? You could knowingly be just a few meters away from rows of corpses, but not really care.
Does the dirt provide insulation?
- Nobody panics when things go "according to plan." Even if the plan is horrifying! If, tomorrow, I tell you that, like, you'll walk through a graveyard, or a morgue, nobody panics, because it's all "part of the plan". But when I bring ONE corpse to a job interview, well then everyone loses their minds!
- I think the corpse acceptability must also account for whether the person expects a corpse to be present.
- People are often uncomfortable in graveyards and, for example, would not want to walk through one at night when they would be willing to walk through a field.
  The dirt does provide a sort of insulation however, as people would be more willing to walk through a graveyard than through a house that had the same density of corpses in the basement. It's the theoretical accessibility to the corpse that plays a factor here.

I wonder if there is a point where the graphs of "perceived effect on the water" cross for both this experiment and homeopathy, and what that means.

It means all of modern medicine is a lie, because the corpse water we drink every day keeps us healthy

The salt water helps.

It's less that there's a specific ratio of corpse:water but whether the corpses have been turned into fish poop yet.

Similar to the water:piss ratio regarding (US?) swimming pools, insofar as the knowledge that the "nostalgic" smell of swimming pools is not the comforting presence of chlorine so many believe it to be, and is in fact the confirmation of a volume of piss in the water that is rapidly nearing the extent of said chlorine's capacity to neutralize (sapped also by ceaseless sunshine & innumerable contaminants hitching rides on patrons' oblivious meatsacs).

In short: if you smell "pool", someone(s) have pissed in it. A lot.

Chlorine reacts with a lot more than piss and you should be far more concerned if you don't smell it.
- Good tip, though the water:piss ratio still stands.

This is like eating bugs. Everyone eats bugs all the time, it is awareness of the bugs and bug to food ratio that tends to cause hesitation.

There are molecules of human shit in every pool and they get into your mouth. The density is just not enough to feel the taste or become ill

That old guy swimming in front of you probably forgot to wipe or wash his ass so the density is getting close to detectable sometimes

As they say the dose makes the poison. See ya at the pool

Thus, chlorination.
The density is just not enough to feel the taste or become ill
the chlorine is a pretty important factor, at least in the not becoming ill department
- Cmon don’t ruin it, I bet someone will skip their pool today
Lots of various kinds of poops on the ocean too...

You leave it in there long enough it might get cloudy enough for you not to see it.

That's when you add the noodles and let it sit for another six minutes.