New tank, need help plumbing

[Saltie]

Hi everyone, it has been a long time since I have had an aquarium. I am just now getting back into it but I need some help. I just got a real nice second hand tank along with some equipment. The problem is that I have never seen a tank with so many holes in the bottom. I have also never seen a sump or skimmer like this. I have no idea how to plumb thins thing……

In addition to the 4 holes I am trying to show in the photo, there is a hole to plumb the built in overflow and one in the back of the tank for the return. I am not sure what to do with these other 4 holes….

If someone could help make sence of all this it would be great. I would like to use this sump (if I can figure it out) plus and additional refug… How to do use these 4 holes to may advantage?

[ret25yo]

allright it looks like closed loop returns in the bottom of the tank. if there is a hole in the back of the tank then that is your closed loop drain. the skimmer looks like a tunze or knockoff (i dont know the model or if it is any good) the sump /filtration you have there is questionable for a reef but fine for a fish only system. the conection at the far left of the picture looks like a copper spicket valve which needs to be garbage. the floss and bioballs will eventually cause high nitrates and can be removed. the black box looks like a tray system for media. JM2c

[Saltie]

Hi, thanks for the help.... There are two holes not shown in the photo... on is in the bottom of the tank for the built in overflow, the other is on the back of the tank for the return.

The part on the sump that looks like coper is really plastic....

How to plum all this stuff?

[ret25yo]

so theres 7 holes total? 5 on the bottom and one upper corner?

if you want to use a closed loop you may want to use one to go to the closed loop pump with 3 being CL returns. the other hole you use for your overflow box to your sump then from your sump to the return hole.

unless you want to drill another hole in the bottom or back to have 4 CL returns.

or you could PLUG the 4 extra holes on the bottom and not worry about them.

[Saltie]

I have been learing about the closed loop systems today. I think i am going to use one of the larger holes for the drain and two small ones for the return, and plug the 4th. next probel is the drain hole is in the center of the tank, so how do i plum in so sand and what not dont go down the drain.... any ideas anyone?