On more sensible note particles entering cylinder won't do a damn thing to the lifespan of them.
Only thing that will shorten the life dramatically is moisture, and that's more down to the coalescers and molecular sieve on the main filters than the add on things.
I'm not convinced the personal filters are big enough to take out all the shit that for example getting the first fill off a compressor when they haven't flushed through the filters from last time will punt out.
Here's my set-up. I have a Coltri compressor. The water-separator removes a lot of the moisture in the air , but it can only do so much. The main filter on the Coltri should remove the rest of the moisture but I'm nervous about it and worry that it's up to the job. I've therefore change the media in the main filter tower more often than recommended which I think means it should be ok. However I also have a secondary stack (from MDE) because I'm a belt and braces sort of person.
I also have one of the moisture eyes that Iain recommends and he's absolutely correct with his recommendation. They are great, but someone in the UK should stock the 10/20/30 indicator cards.
 Imagine some 1000 litres of air at 30% humidity. Compress it to 200bar and you have 5 litres of air at 6000% humidity. 6000% humidity is impossible, so 59/60ths of that will drop out leaving you with 5 litres of air at 100% humidity. When that expands to 1 bar again you have 1000 litres of air at 0.5% humidity.
Where do you get the moisture indicators?
Remember anything you read on the internet was probably written by some guy sitting at home in his underpants! Including this !!
Illegitimi non carborundum
A number of observations,
1. From the Nuvair photo you would'nt put a steel spring behind a pressure viewport without using some protection to avoid scratching.
I dont know if you have ever visited a hyperbaric chamber or been in a closed diving bell but tapping the "glass" is highly discoraged.
And a scratched "glass" is a possible good reason to replace. I used to hate it when some numpty would use their ring finger to tap
the viewports on the chambers offshore. I'd wait until they were inside themselves then wack the chamber shell with a lump of 3x3 wood, they only did it the once.
(I'm a certified PVHO-1 (Pressure Vessel Human Occupancy) viewport repairer. You can tell by the tins of Brasso around the workshop and the big stick LOL
2. The American replacement indicator card is not the same as we use over here. They use a combination CO and single 40% display humidity element
And in keeping with scuba sports stuff, the CO dont work until your a 50ppm and probably dead and the water display only works when your paddling in the stuff
Not unlike the Personal filter junk some of us here continue to argue being a possible solution to extending cylinder life. Joking apart.
3. By contrast the UK use a much more sensitive and accurate triple display of 10% 20% and 30% relative humidity in keeping with current BSEN 12021
breathing air quality standards from a stored gas bank above 200 bar. And a 20/40/60 indicator card option for a portable compressor up to 200 bar.
The other option is use the 20/40/60 off the standard compressor filtration stack and the 10/20/30 off the second fiter tower.
All visual indicators need to see pressure at all times so are set up after the filter but before the back pressure regulator BPR or Priority valve on the filter.
By contrast hold the bare indicator card in your clenched fist and it will indicate in around 10 seconds just by the sweat pours in your hand increasing localized humidity. I feel an experiment is required.
Last edited by iain/hsm; 11-06-2019 at 06:24 PM.