2 smaller sumps for large tank?

[Mlarson]

I have a 125 gallon tank that came with a stand that is two smaller cabinets with a open space between. The cabinets could prob fit a sump that is good for 75 gallon, so I could I use two independently to get the job done? Cabinets are roughly 23 wide, 16 deep and 25 tall. Thanks

 

[MaxxuM]

Optimally, they should be plumbed together, or large enough on there own to deal with any overflow issues if one gets clogged or a pump fails.

 

[RocketEngineer]

They must be tied together or they won’t balance. There needs to be a single low point in the system with everything gravity fed to that point. Otherwise, you will have a situation where one pump slows, the ATO keeps adding water, and you either crash the salinity or overfill the slow pump and dump water on the floor. It can be as simple as a pipe connecting two return sections or make it the inlet for external pumps.