I have bought this Tanks Rack which has a unique design.

each shelve has its own built-in sump and there is a small gap which fit a paper (Not two) between the sump and tanks. The owner told me that the design to serve the dripping system and the built-in sump actuallyis areservoir to fill the tanks.

There are drain holes in the built-in sump and the tanks and many potentials to use them and I'm not sure how to use them properly for the shrimps.

The options are:
- Drain from the Sump to the below Sump
- Drain from the Sump to the below tankswhere the excessive water return to the sump
- Install a sponge filter in the tank hole and let it drain the water to the below tanks

I do prefer the last option because I don't need big air pump to serve the 15 tanks and the draining from the tank holes with the sponge filter will build the bacteria culture in the sponge. But I'm not sure if this will impact negatively the shrimps babies!

I'm not sure which option is the best. I need your input please