Yes, I vacuum my substrate the best I can with every water change. Tank is 29g with a ton of plants (all live - frogbit, guppy grass, crypts, java fern, giant hygro, wisteria, amazon sword, moss ball, duckweed, and a few other species). Ammonia and nitrite are both at 0. Tap water reads 0 across the board. My pH is over 8 in both the tank and the tap. Just did a 50% water change today and checked nitrates about an hour after and they are still between 20-40ppm. I did acclimate the loaches, and like I said they all seem to be eating fine, just swimming around a lot. My platy just gave birth last night (all babies got eaten)...as for high bioload I think the three platys I have are the culprits there - they CONSTANTLY poop. Otherwise I have female bettas, corys and otos plus a few amano shrimp and a bunch of MTS. My tank is fully stocked after the addition of the loaches, another reason I always do 50% water changes.
As for my mom's angelfish, I'm not kidding every time I check her nitrates they are off the charts and her angels spawn every couple weeks. She doesn't clean her tank as often as she should, about twice a month and she has the same filter I do. And yes, they are definitely pearl angelfish, lol.
On a side note, I live in MN and the weather has been a bit weird lately...super super hot yesterday, colder and dreary today, supposed to be ridiculously hot again tomorrow with possible storms...I've been reading that kuhlis sometime go nuts with changes in the weather...wonder if this is as simple as that?