There are multiple issues that people are discussing, and they are unrelated to each other.
Bear in mind that very few people are complaining of actual problems caused by the Brutes. Most are complaining of test results they are getting, not problems in their tank.
Those who are complaining of tank problems have no evidence that the Brute is an issue. Some above complain about algae and pods and cyano, etc. Well, that happens in a ton of tanks without Brutes. There are literally thousands of threads about people with these problems and no Brute cans. There is just no evidence that the cans are a problem from this perspective.
So to the testing issues. A clean Brute can is not going to raise the TDS to 830 ppm TDS by leaching salts from the plastic. But a can with even a trace of salt dust, spray, or a bit of leftover salt mix will do so. Even if it looks dry, there can be plenty of dried salt to push the TDS up substantially. People find the same in any types of container. It is not easy to get a container clean enough to keep the water at 0-1 ppm TDS, and if open to the air, it will rise over time if anywhere near salt dust or salt spray, etc.
As to the phosphate, people really seem to get crazy about tiny traces of phosphate. Yes, people get values with Hanna checkers of maybe 10-20 ppb. Even if real, these are not significant. One feeding with fish food adds hundreds of times more phosphate than people are adding using the water from their Brute cans for top off. No, the 1 ppm phosphate reported above is not normal, and is not from the can itself. Many people have studied this and do not get those levels. I expect that can was contaminated with something (hence the high TDS as well). Perhaps it had bird poop in it from the store, and never was rinsed well enough.
Finally, Eric’s saga. Eric did an experiment with some delicate creatures and when they died he blamed the can with zero knowledge of the chemicals put into polyethylene cans and no actual evidence it was the can. He mentioned plasticizers, for example, when they are never used in polyethylene. Just a lot of uninformed scare mongering on his part and lots of the folks in his thread that know even less about plastics. Could it have been the can? Possibly. Could it have been something in the plastic? Possibly. Could it have been bird poop? Possibly. He doesn’t even say whether he cleaned the can prior to use.
While I frankly do not care if people like or don’t like Brute cans, and use them or don’t use them, folks should be realistic about their use. Of course rinse them before use. If they look dirty, clean them well. That said, many, many folks use them and do not have apparent issues. I use 12 of them, and the ones serving as my refugia are loaded with life, pods, sponges, coralline algae, macroalgae, etc. Could they be less than optimal and I just got lucky? Possibly. But there are many cases of folks using them, and that isn’t really balanced by a few (very few) claims of actual problems and a larger number of test results (like phosphate) that worry folks but realistically are not any sort of problem.