if i had a dollar for every koralia that quit on my id have a few bucks. that said i still think they are great pumps and worth it
I think you just need to weigh your options. Korallias are nice from what I hear, but a small investment with a higher fail risk would be a deterrent for me. IMO I'd stick with a tried and true manufacturer and spend the extra bucks....but thats just me.
Are your #4's on a Timer to come on and off? If so that could cause some issues as well.
55g with (2) 250w MH electronic ballast w/ Reeflux 12k
SPS reef . 2-Koralia #3's , 30g-ish Sump.
RedSea Berlin Turbo Skimmer, Teco Chiller