I'm not really a fan of the 6-inch cover even though certain brands sell it as something their entire team can stand on, it is unnecessary if the cover is made correctly. Six inch covers are bulky and when they get water logged they will be so heavy it will take that team standing on it to haul it off. Besides that the expense doesn't outweigh the cost unless you consistently have tons and tons of snow on your cover.
Even though we sell them (quite well actually), I would tend to agree with this statement. I still think our 5"x3" 2# foam models is a better overall value if you're looking for an upgraded cover. If you are thinking 4"x2", I would still go with 2# foam. It's stronger, insulates more and doesn't absorb as much water.
In the mountains of Colorado we destroy covers pretty fast with our UV rays being so intense, our hail, our snow coming in large amounts and then melting the nest just to the point that it leaves a sheet of ice on top.
High elevations are one of the only areas of the country where we tell people it may not be the best thing to spend a ton of money on a cover. The UV intensity shreds the vinyl. Spa covers are typically replaced when the cores get too heavy. In the mountains, the vinyl is the first to go.
Buying a cover with heavier density foam, better seams, better vinyl (with UV Protection) and better interior wrap is the way to go.
Outside of some of the big cover manufacturers doing the OEM jobs for spa mfrs, most cover manufacturers buy from one of three vinyl sources. They all feature pretty good UV protection. Not to single out the big guys, but since they buy their fabric mill direct (usually from mainland China), I don't know what specs are in their vinyl.
The rest of what you say is spot on. That is spa cover 101 in a nutshell. It just comes down to budget because you get what you pay for.
More importantly, how you clean your cover, what products you use, how often you flip the foam and whether or not you use a cover lifter and floating inner cover will decide how long the cover lasts more.
Cleaning: Mild detergent + water; Natural Chemistry BioClean; ecoOne Cover Cleaner
Moisturizing: 303 Aerospace Protectant (we've recommended this for almost 20 years); Leisure Time Cover Care; saddle soap
Flip the cores once a year
Cover lifters are great but wear the center seam. Use Cover Saver or switch to tray-style removal system like Cover Caddy.
Floating covers can greatly increase the life of a spa cover. They will need to be replaced every couple years though.
One manufacture claims they "Pour" their foam so it's less likely to absorb water, this is just a claim and never verified. Most cover manufactures use a hot knife to cut the foam and thereby seal the edges but the "Inner wrapping" is what really makes a difference here.
This would be Arctic. They are great covers. It's injection-molded and since molds are so expensive, they are basically only available for their tub sizes. You shouldn't have to replace this cover, ever. But if you do, be ready to write a big check. Seriously though, has anyone ever had to replace one of these?
