Gross but serious question...... I read that there has been found traces of fecal matter in swimming pools from people not cleaning properly after going to the bathroom, would this cause issue for davening immediately after going swimming without showering first or since it is SO diluted by ATLEAST several thousands of gallons of water would it not be a problem halachicly?
See Brachot 25b
אמר אביי צואה כל שהוא מבטלה ברוק אמר רבא וברוק עבה .
See SA OC 76, 6 : If that is a very hight dilution it is halachally meaningless.
From Yoma 30a two rules:
See SA OC 76, 4 : If a part skin area, except for the anal region, and this area is covered by clothes, he can pray and recite Kriat Shema.
See [SA OC 76, 5] and Magen Avraham sk 8 : If the anal region is not clean and there is excrement or a smelly seepage, he cannot recite KS or pray despite that this area is covered by clothes.
The excrements traces are not perceptible by odour or color in the swimming pools, so there cannot be significant in matter of prayer, blessing or Kriat Shema (the knowledge about excrement traces is important from bacteriological and viral point of view, not for the hilchot Tsoa.).