I have a Blueline 55 HD External Water Pump with 1in MPT in/out and a Nu-Clear 533 for Mechanical filter and a Nu-Clear Model 547 with Bio Balls for Biological filtering. What would work the best for a intake and return. My 125g tank is not drill. I've use this system 1 time and had nothing but heat issues using pvc elbows , unions, ball valves ect: I end up replacing it with Eheim 2262 . I was hitting 90 degrees with pvc and when I change everything over too vinyl hoses it drop down to 84. I never figure the problem out With my Eheim the temps were down in the 70. My tank has not been setup since 2013 and would like to fire it up an try these filters again.