aquired new system : sump/skimmer plumbing help

I aquired an AGA 75 drilled aquarium with a proclear 150 sump which includes a skimmer. I have a few questions. I looked online and found that the plumbing that I have is the same that comes with the sump. I don't know if this is the best way to do it though. The intake to the sump has some kind of compression fitting thing. The return line from pump to tank is a clear vinyl or whatever hose. Is there a better way to do this. Should I hard line this and install a ball valve? Also, the pump is rated at 700 gph. The tank overflow is rated at a max of 600 gph with a 2400 gph return pump. I have no idea what kind of flow through 700 gph will give me and how much I should want.

I also have a question on the skimmer. See pic, I've never had this before does the small line with valve off the pump go into the small hole on the top of the skimmer? Also why is it T'd off the skimmer pump with the other part of the T left open.

thanks much for helping


Tank Overflow Intake (left) Return (right)



Sump



Skimmer

 

I would put in a check valve for sure. You want that to avoid a flood. As for the return to the DT- that is really preference. I prefer to use PVC but do know many folks use vinyl tubing. My main problem with the vinal tubing was that I did not like the power head that hangs on the back of the tank. Just did not look like a sturdy piece at all. As for your turnover -- with that pump you will likly see around a 9x turn over rate per hour. maybe a little less if you put in a ball valve (and guessing that the powerhead is about 4-5 feet above the pump.) Attached are some pictures of what I did. I have a check valve to stop flooding, then have two ball valves the lower one is for water changes and the higher one shuts off flow to the tank.

As I said what you have will work as long as there are no leaks- I would just add a check valve incase of a power outage.