grain sediment during sparge

I just got into all grain, 4 batches now, and I am curious about grain sediment present during sparging. My first batch (dry stout) had no sediment after recirculation. My second batch (Burton Ale) had an enormous amount of sediment present during the entire sparge. It was not enormous pieces, but it was alarming to see. My third batch (oatmeal stout) was a little cleaner, but not ideal as far as I am concerned. Today, I helped my roommate brew his first AG (APA) and there was a pretty minimal amount of sediment. I use a 5 gallon rubbermaid cooler with the stainless steel concave false bottom and batch sparge. I have two questions. 1- what are the possible reasons grain can continuously find its way into the sparge, even after a thorough recirc and 2- what is an acceptable amount of sediment during sparging. I just tasted my first AG beer even though its only been bottled for 2 days and I now understand why I switched from extract

You definitely want to keep the draff carried over into your boil to a minimum. It can cause haze and off flavors.
It sounds like its getting under your bottom where it meets the cooler. I believe I remember reading someone taking a piece of vinyl tubing, slitting it
down the length and putting it around the edge of false bottom so it acts like a gasket. I don't use a cooler so you may want to search it to get better details.
Hope this helps.

If grain is getting around your FB, this is the cure...


Cheers!

That is beautiful! But what is it?
Thanks for the reply.