Question about return system on several large tanks(600+g volume)

Deftec · Oct 5, 2014

I am in the process of setting up a large volume system which will incorporate several tanks. I have a question regarding the return system I am pursuing to use. The Display tank has (3) 1'' lines coming out of the overflow box, the 2nd display tank has (2) 1'' lines coming off the same side of the tank. They will all run under the house and back up into a 100g sump, with there being roughly a 6.5' difference between the bottom of the sump, and the top of the main display tank. The 2nd display tank, however, is a few inches lower than the display tank. They are all being tied into a 2'' line under the house.

Will the difference in height between the display tanks affect the flow on the 2nd tank? Or with the sump being significantly lower allow the water to properly drain?
Any suggestions as to anything I should change for this? I haven't built anything except the manifold that will run under the house

I just got to questioning this due to the volume and weight of water from the display tank and wasn't sure if it would slow the flow out of the second tank.
The picture I attached isn't the greatest, but it gives an idea between the differences in height and the way I am thinking of draining them all.

The pump will feed 3/4-1'' lines supply water to all the tanks and have a manifold to control flow to every tank along with a line to the bottom sump to control pressure(similar to a car fuel system). Thanks!

Reefing Madness · Oct 7, 2014

stunreefer · Oct 7, 2014

Your drain lines per schematic looks fine to me (not sure what's going on between sumps but that's not your question). You shouldn't have any issues with the one display being a bit lower than the other since the drain line they're tying into is well below both displays. Obviously avoid elbows like the plague as you want the drain flow to be as free as possible. I have ran into issues with multiple drains ran together (into one 2" drain for example) where air bubbles were forming in the plumbing and would cause some odd backflushing issues in the drain piping. In one instance I ended up running dedicated drains to both systems as everything else we tried wouldn't work. Unfortunately there is no hard fast rule on how to avoid this unless you really get into fluid dynamics, which I don't

My advice again is just to avoid fittings, particularly elbows whenever possible creating the straightest run to the sump.

Deftec · Oct 7, 2014

I figured gravity would allow it to take the path of least resistance(to the sump). Just wasn't sure if the additional weight of the display tank would slow the drain on the 2nd display tank due to difference in height. I wouldn't imagine 3-5'' of 1'' tubing would make much weight, but before I have this thing filled it can't hurt to ask haha. I'll be using 45's for the two upward angles into the sump, unfortunately the way my home is designed doesn't allow me to run straight down into a sump due to no basement, and my garage floor is slightly lower than the main floor. The two sumps are stacked on top of eachother, just using those for volume and misc holding(liverock, copepods, etc). The manifold that ties them all to the 2'' is also angled where it's tee'd, I just made a quick illustration, I can provide pictures if needed.