sump question

i plan on making my own pvc overflow with 1/2" pvc pipes, i was told that 1/2 pvc pipes would require a 600 gph return pump? is that true? my sump/refugium design would be 2 10 gallon aquariums(i cant go any bigger because my stand doesnt have the correct dimensions):

intake from the main tank through the DIY pvc overflow through a series of 1/2" pvc pipes into a 10 gall refugium, at the other end of the refugium would be another 1/2" pvc overflow connecting to the sump under the refugium. in the sump would be a drip zone where the intake from the refugium would be. then i geuss i would be using a 2300 visa aqua return pump(600gph) going through 3/4" airline tubing and 3/4" pvc pipe into the main tank. would the drip zone where the intake from the refugium to the sump be a bad idea? instead of having another 1/2 pvc overflow from the refugium to the sump should i drill a hole on the side of the refugium connecting to the sump using just a pvc pipe filling the hole then connecting to the top of the sump? this is for a 55 gallon main tank.

 

You want your return pump to out perform your overflows. This way you do not overflow your sump. Just make sure you have a T coming off the return line with a valve so you can control the flow back into your sump and dt.

 

Actually the pump will control the flow through the network to the handling capacity of the plumbing. Get a pump that has 100gph to 150gph at 4 foot head as your return pump.

 

Here is a link to gravity fed flow rates for a given size pipe GPM/GPH Flow based on PVC Pipe Size, ie, How much water can flow through Sch 40 Pvc Pipe Size 1/2" 3/4" 1" 1.5" 2" 2.5" 3" 4" 6" You do not want to have the return pump exceed the max the overflow can handle. If you are using one 1/2" pipe then your return can't flow more than 420gph. More than that and you will overflow the tank because the overflow can't keep up. Ideally you should use two overflow pipes, one a little higher than the balance point as a backup in case the main pipe gets clogged. 1/2" pipe has a greater risk of being affected by the normal build up of crud, snails, ect. because of it's small diameter. Either way you will want to set the height of the main overflow just under the normal water level to start with and find the exact height while the system is running. Adjust higher or lower to find the balance. Usually low enough so that it stops flowing when the sump is just below full. That way during a power outage or pump failure the sump won't overflow.

Ex: Using one 1/2" pipe from over flow to sump (420gph max). You have 5 ft from the bottom of the sump to the highest point of the return pipe. Say the return pump flows 600gph at 0ft and 400gph at 5ft. This would be acceptable. Much more and you're taking a chance.

 

return pump sets flow rate, but you still need to balance things. Pressurized flow in a 3/4 line will out do a gravity fed 1/2 line.

There are plenty of single line overflows, but it needs to be bigger than your return line because it is only a gravity fed stand pipe overflow. A 1/2 line for the pump and a 3/4 line for overflow would be more like it. If you want a 3/4 pump line, then you will need a 1" overflow line.

Also.... you do not care what line is from the fuge to sump. Make it as big as you can just so you know for a fact it will not cause a bottle neck. 1"-1 1/2 is not that crazy. What happens if some algae get's in there? As far as how to do it, always let gravity do the work from you. Side by side or on top is not a big deal... but if you do fuge on top of sump then you can set sump level with baffles and not have to do the same level as the fuge next to it.