Is there actually any difference between Cascade Platinum and Platinum Plus?

You're running into classic diminishing returns. Regular Cascade Platinum is alredy an aggressive detergent packed with plenty of enzymes and surfactants, so standard baked-on pans aren't going to look noticeably diferent with the Plus version.

If you check P&G's SmartLabel database instead of the standard safety data sheets—wich only list hazardous chemicals, making both look identical—there acutally is a slight formula change. Platinum Plus has a tweaked polymer blend and a marginally different enzyme package designed to suspend oils better. They also reshuffled the liquid chamber volumes, which is why the color switched to purple. But more liquid volume doesn't equal more weight; liquid detergent is less dense than compressed powder, so shifting the ratio naturally drops the net weight per pod while letting them market "more grease fighter." As for the filter claim, that's almost entirely marketing hype. A detergent can't defy physics. If your water isn't entering the machine hot enought (ideally around 120°F to 130°F) or if you wash heavily soiled items on short cycles, animal fats and proteins will still collect on that fine mesh screen over time. Pod enzymes help break down residues, sure, but you're still pulling that screen to rinse it manually every month or two.

Unless you're dealing with ridiculously hard water—talking 15+ grains per gallon—or never scrape your plates, regular Platinum is already overkill for 95% of loads. Save the cash and stick with the regular tub.

I'm super new to owning a dishwasher so this might be a dumb question, but how do you actualy check your water hardness to know if it's over 15 grains? Is that something you can just test from the kitchen faucet with a strip?

Also, if regular Platinum is already that strong, can using these aggressive pods on softer water actually cause that cloudy film on glassware? I always assumed cloudy glasses meant they weren't getting clean enought, but I honestly have no clue how the chemistry works.

Save your money and stick to the regular ones. I grabbed a tub of the Plus when it was on sale at Costco to see if it’d help with stubborn scorch marks on my stainless skillets, and it did zilch compared to the green pods.

What actually fixed my cleaning issues had nothing to do with the pod formula. I popped off the bottom spray arm, cleaned a bunch of seeds and hard water gunk out of the tiny nozzles with a bent paperclip, and started running the sink tap untill hot before starting the cycle. Dishes come out pristine now with basic Platinum.