I know on our outdoor cooking tables we use the heavy duty from SAMs and it lasts a whole weekend of sliding pans and utensils on it, we probably wipe them down 10-15 times minimum.

Only diffrence I see is the table is smooth the downspout is ribbed.

I use the cheapest stuff I can buy at walmart.
I don't clean off dirt or animal droppings. (caterpillars leave way more mess than birds or raccoons) Algae has not been an issue since I've got the whole thing enclosed. Nutrient salts don't build up in an NFT system either so it shouldn't be a problem. Even if they did, they're inside the channels and the aluminum is outside
A hose won't tear the stuff but I suspect scrubbing it would (were it is not glued down) However, even if you do tear the foil, you can simply glue a little patch over the tear.

Thanks. I guess the aluminium works well for a cycle or two, but I have thoughts of creasing and dirt since even cleaning off my brand new rails was a Beach, and still not really done. If the investment in the big rails wasn't over $200 and just cheaper gutter I wouldn't be concerned.

I had planned to go with paint, but there are no perfect answers. The solvents in the PVC paint which are supposed to dry out aren't environmentally friendly at all. Supposedly that isn't a problem though because all the time manufacturers recommend painting potable water PVC for UV protection. So when Grizz wrote about the foil it seemed like a better and cheaper idea done properly, but I'm not sure what sort of moisture you are dealing with.

I think I'll probably make another ~2x3" setup and learn that way attaching the foil. Can't afford to replace the big rails because three years later I'm cussing rubbing mineral spirits into them to reapholster the old foil in this overgrowing place.

Getting an appreciation for the removable lids of the commercial NFTs before I even start ...

I sounds like you are more concerned with cleaning than me. I only clean my system between crops and on the rare occasion I get a really icky something growing in it.

It is really humid here and has been raining every other day for a few months. I can't even get the algae out of the deck and that is treated wood. It was really not fun to get the crud out of the new rails, they are thick 5"x5" by 8 feet and not easy to deal with. Not at al like the 2x3.75" thinner wall rails I got to make the rooting nursery.

I don't know what the crud was but some was sticky, had algae and it didn't sit outside all that long. Probably my cleaning method is to blame and next time I might just spray bleach in there and it might make a huge difference.

Well bleach will kill stuff but it won't get it out of the system, physically.
My first go w/ the 2x3's I had lond strands of algae growing in all the water. It even clogged up my pump on occasion. After I covered everything with aluminum foil, I only have sparse algae growth where light leaked in around the edges of the net pots. That much(or little really) algae, I can live with.

Hey Grizz thanks for the always good tips. So, maybe a giant pipe cleaner (like a mop) to push through for me, like your startup mine still has something unpleasant in it, hey this was supposed to be fun!

I waste 10 minutes every day to keep a deck clean or have it rot quickly from the crud that mother nature makes every day. Sometimes I have to take a toothbrush to the grain of the wood or a butter knife to the planks like a dentist because of the organic residue. Even aluminum elsewhere here gets a whitish oxide of some sort on it.

The soil is rather acid and there is a big stream 15 feet away complete with ecosystem. If I put lettuce too close, no deer LOL. But a one-ton Manatee flops up and will eat it. It eats like a cow, munching can be heard for at least 50 feet! Thanksfully the 30' ft high muscadine grape tree cover stopped fruiting so the squirrels can stop bombing the deck (garden and all)with all the grapes that shoot out of their skins

I was more worried in this situation to know whether small ridges would develop on the aluminum, or if the glue kept it flat on the outside, as the channel aged since everything I put out there turns into a cleaning chore.