This sounds like possible contributing factor, as your water storage should not smell - you wrote:
55 gal barrel used previous for some mash crap that smells awful everytime you open the lid, but I was told so long as I cleaned it up and everything it should be fine.
Bleach it and get it actually clean. Rinse it out well, and use declorinator if nervous afterwards.
Also, completely agree your tested water parameters are nowhere near what you think due to the explosive growth of algae which needs nitrate/phosphate/light for fuel.
Also there is no mention of room's lighting and/or proximity to windows. My gorgeous southern facing windows that used to fill this fish room with sunlight have not just wooden slat blinds but also solid barrier between each window and blind.
Finally, here is my magic algae scrubber that during water changes, I lift out each rock, scrub rock out of the water (so algae actually all leaves tank), rinse rock with water that was getting thrown away anyhow and then rock returned. My flexible scrubber is made in part from actual scrub brush from home improvement store, so it has that awesome stiffness, but to get into rock crevices, bristles are cut off brush and stuffed into bit of spare tube, then bead of superglue run around outside edge to hold in bristles:
Yes, it you think it seems more bristles taken than you see used, you are correct. You can wear out scrub brush bristles if you scrub often enough, and I've lost count of how many built though each lasts for months.