Briefly, it is ok, on long addiction sobering

This LED Strip are coated with a silicone layer that was for me the reason that I can block for outdoor lamps,
In the short term of 8-10 weeks, the LEDs operate tadelos, several hours a day, after about 3 months it begins, the LED will slowly darken. The are also very warm. Right down to a barely lit LED.
Also, the silicone is slowly light brown

Thereupon I have tests done, in 15 LED I have removed the silicone to burn after 4 months still like the first day and 15 LED with silicone. These LED are indulge become darker.
The other experiment was that I gave you 40x40 mm LED's cooled with a small PC fan, keeping the longer.
Because of this, I can only tell me that the silicone retains heat and is not transported away. Due to the heat the LED break.

About Pollin.de I ordered LED strips, but without silicon, which are much better suited for long-term duration.

Finally, as Waterproof LED Strips, I personally recommend a transparent thin tube, if one intends to use as an underwater lamp / light, which are by the water, that around the hose moves / flows / is cooled.