Connecting two sumps

[TJQ]

Due to limitations of my stand and the size of my skimmer cup, my system will require two sumps. They both will be 28 x 19 x 16" tall, and will be about 30" distance between them. What I am unsure about is what size of pipe I should use to connect them. Would 1.5" do the trick or would I need something like 2" or even greater? Thanks!

[Steve175]

As big as possible. Also, if possible, raise the proximal sump to encourage gravity flow into sump from which return pump originates.

[Alex T.]

I have 2 one inch drains feeding a 27 inch rubbermaid tub. From there they flow into a 29 gallon refugium through 1 one inch bulkhead union. This way, the return pump in the refugium pulls at a consistent rate and water in the Rubbermaid tub fills a little higher and keeps water a bit longer for the skimmer to process. If you have baffles in the first sump you could possibly create a problem trying to match the flow to the bulkhead fitting going to the second sump...been there done that. If a larger diameter or more than one pipe is used to draw to the second sump you could have inconsistent evaporation rates in each sump, causing salinity problems. This is in due part to less resistance which allows for easy flowing water exchange. My first sump with skimmer always stays at the same level and water is pulled like a vacuum to the second sump in the refugium with the force of a powerhead that keeps the chaeto tumbling. My first sump with the skimmer never changed in water level, which allows for more accurate evaporation rate replenishment.

[TJQ]

Alex, thank you for the response. My current plan is this:

Left Sump
-28" x 19" x 16" (~36.8 gallons)
-Gravity fed by a 1.5" Herbie Drain from overflow (300 Gallon Display)
-Vertex Alpha 300 will live here

Right Sump
-28" x 19" x 16" (~36.8 gallons)
-Connected to Reeflo Dart Gold Pump

If I understand you correctly, then the water in the left sump will be vacuumed into the right sump similar to how your system works.

My follow up questions would be:
-Would you use a single 1" or 1.5" to connect them?
-Which Sump should my ATO sensors go?
-Is it best to have my two part dosing tubes go into the right sump? (I assume it would be to keep it away from the skimmer)

Thanks!

[jdg]

As suggested above, go as big as you can. My two sumps are interconnected by dual 2" bulkheads. The last thing I needed was for one interconnect to clog/jam and have water all over the place. ;)

[TJQ]

As suggested above, go as big as you can. My two sumps are interconnected by dual 2" bulkheads. The last thing I needed was for one interconnect to clog/jam and have water all over the place. ;)

I know I know :) But if you look through Alex's post he suggests the exact opposite if I am understanding things correctly.

[biecacka]

my dual sump is connected by 1.5inch bulkheads with vinyl tubing in between them. i actually have one drain from my DT goining into each sump to keep water level equal
corey

[iamwrasseman]

i would suggest that you use 2" bulkheads Say you can get some surging between the two sumps which will be annoying and the larger the holes the smoother it will flow . along with the ability for it not to clog due to unforeseen circumstances that are out of our control .carbon bags ,cheato ,etc can be a problem if they get to the bulkhead so bigger is better IMO.

[TellyFish]

I also used 2" to connect my 2 sumps to avoid clogs which would cause a flood.

[biecacka]

id used 2 inches if i could have found one