My mitake I use the RD 20 . Been toying with use of rd 3o because it has the flow i want 10gpm but it also has some thing i really don't want. Added noise but the use of 2 allows me 10GPM witch I want . Dave just told me I made mistakes above as 2 RD20 are required and y blocks are in fact used sorry about that . But we preferr the Alphacool pumps as their more versatile for our use thats the plus . The minus is they require more room thats the - . Insid the lian li caseits not a problem as far as space is concerned, As we completely redid the cas interior to fit our needs . As well as the face plate and side panels.