I am setting up a 150gal. that will house 2-12" oscars, 1-10"jag, 1-14"pleco, and 2-4"tinfoil barbs, will 2 350magnums or a rena filstar xp3 do a better job?
2 mags would do a better job. have you thought about a wet dry filter? they are great for bigger tanks. most likely would be cheaper and better then the mags and rena.
if you went with the xp3 i would get two of them if not more.
i am not sure exactly , i have 0 expierance with wet/dry filters, but have used canisters before, my tank is pre drilled . are the wet/dry filtery fairly easy to maintain for someone who is technically inclined.(i'm a carpenter / decent plumbing skills)
I have a 155 gallon nothing as dirty as oscars in it I have qll 3 of these filters well one is a xp4 i dont really like the 350 the return flow isnt that good so know i use it to run uv light. i like the flow of the xp you might want to step up to the larger size there are good deals on ebay got mine for $100 new.They also have way more media choices you can throw bio balls in . and i have a proclear 300 gallon wet dry running ata return rate 0f 975 gph it works pretty good. I do like that my magnum came with a vac attachment that works great but it clogs easy thanks
The flow on the Mag's isn't great and for what you pay for 2, take a look at a Fluval FX5. 925 gph and the canister is the size of a 5 gallon bucket. Been running one on my 180 for a few months and its super quiet and powerful. You can find the fx5 on ebay for around $250 shipping included new!