Tank plumbing

picture can help.. being freshwater it might be tricky....

Normally saltwater tanks have over flows to skim the surface.
Freshwater is the total opposite... things sink in freshwater so you need a bottom intake.

So.. to answer your quetion.. you can run a bulkhead in the upper right corner and screw on an elbow-thats your intake

The hole on the bottom is possibly the return...(pictures to confirm)

and you would just plumb all of the intakes to on size tube or pvc so it connects to you canister.

the return would be running on a single tube and split to 3 , each going tos own way to the tank's return.




once again if you have pictures i can draw it out for you

It would also have to be a heck of a filter to keep up with 3 x 6 footers...

But likewise, I'd rather each tank separate...

If you are going to run them all on a single HUGE filter then I would add a UV staralizer to help cut down the odds of any thing spreeding. I tank for tank filters but understand sometimes its much more efficant to run a single filtration. If I was to run this system I would get a UV staralizer for each tank if I could afford it and put these at the tanks return. If you cant afford it then at least get a suitable sized UV for the return line that all the tanks share.