What sized media reactor

[Wspangler]

Hi guys I have a 125 with 2 20's tied in. 165 gallons, but less with the rock, sand , equipment ect. I'm not sure on how much less but I'd imagine I sit somewhere around 140 gallons total. If I'm reading correct I think this would be around the maximum the mr5 could handle. So there's my question

Mr5 or mr10

 

[shifty51008]

the MR5's will be plenty big enough, thats what I run on my 75 gal display with 150 gal sump/fuge