tunze nanostreams?

[fiorano]

so i have been running 4 tunze nanostream powerheads for flow in my tank and i was jsut wondering how other people feel about these? they only do 1800 gph in water movement and i just had my second drive shaft shear off which is not covered by warranty. seeing as my tank is mainly sps and i need a lot of flow are the koralia's a better alternative? i do like the nanostreams because of the compact size but i cant have them always breaking on me and forcing me to buy a whole new engine block.