The only guarantees...... death
Careful examination of fish condition before purchase and confirm fish will feed on offered foods are a must.
And do they poop?
Used fish are a bonus
Good luck
The NSW is filtered to 5 micron and then 1 micron pleated canister filters.
I HAVE found muscles and eucid worms at the bottom of my reservoirs in the past!
But like you G, I’ve been through 1000’s of gallons
IMHO
Red Sea brand…
I would stay away
Or at least make sure your insurance is up to date and will cover the failure
And if you must go with a Red Sea tank, buy it new with full warranty