Ok I goofed

[stingeragent]

Ok, just wanted to post this to for-warn anyone from making the same mistake building a sump. So I'm running a herbie on a 40G, both 1/2 in drains. My return pump, I did kinda weird with like 1/4 flexible tubing. It's been up several weeks now but just felt I wasn't getting enough flow through the sump(running an eheim +2000 around 550gph pump) so i decided to calculate return flow using a 1 gallon bucket. Took just under 2 mins to fill a 1 gal bucket which worked out to like 30gph. Wayyyy low. That was a couple days ago. Today, I decided I would hard plumb with 1/2 pvc minus a small 3/4 flex hose connection to the pump to avoid vibration. So plugged it in after everything dried and my return pump drained the return section in seconds. Unplugged the pump, opened my gate valve on main drain and added about a gallon of water. Plugged it back in and same thing. It backed up the main drain and my emergency was running almost full steam with all its loud gurgling goodness. This pump is adjustable, so I dialed it down as low as it would go, and same thing. So in hind sight, now that I've done the return properly, I should have went with 3/4 main drain's at least. Sigh. It now looks like I have no choice except to either gate the return, or run a T back into the refugium.

 

[sleepydoc]

This is an excellent example of the effect pipe/tubing can have on head loss and flow. One of the first thoughts I had as I read your post was "½" pipe is *really* small for a Herbie!" And ¼" is almost useless for any sort of flow. The only tanks that should really be using ½" pipe are nanos. ¾" pipe is not that much bigger in terms of actual pipe size, but you get 50% more lumen, meaning up to an 80% drop in resistance in flow.

Where are the bulkheads placed in your tank? Even if you're stuck with ½" bulkheads, you can still upsize the pipe and improve the flow.

 

[stingeragent]

Bulkheads are in top left. If I increased all the pipe after the flow to 3/4 would that do anything? It seems like it would still be limited by the 1/2 bulkhead

 

[jonwright]

Depending on what you have (slip vs. threaded) you might be able to salvage what you have here. The intake and overflow pipes needs to be 3/4" - even with the 1/2 bulkhead. I'd hope that the bigger pipe diameter pipe may cause less restriction and allow more VOLUME of water through.

Doesn't hurt to try. And measure the hole. If you can fit a 3/4 bulk head it makes things easier if you put one in.

 

[sleepydoc]

Yes - the ½" bulkhead will still restrict flow, but plumbing resistance is additive, so larger pipe with a smaller bulkhead will still help some. If you pick up the new plumbing parts, you can probably get most of it set up, so you can just drain the tank partway, replace the plumbing and fill it up again.

 

[skeeter_ca]

Make sure the 3/4" pipe is thin wall, and that's a lot more with flow.

 

[sleepydoc]

+1 - good idea. It's actually called SDR-21. For ¾" pipe, the I.D. is 0.91" vs 0.8" for schedule 40, so you're getting about 30% more area.

http://www.harvel.com/technical-support-center/dimensions-pressure-ratings/pvc-pipe-sdr-21

 

[stingeragent]

Ok, small update. Temporarily I decided to put a valve on the return plumbing as it was a much quicker fix and haven't had the time to redo both the main drains from scratch. So I dialed the return back about 50% , and plugged the pump back in. After everything started circulating my emergency was quickly getting used again, so I was thinking theres no way with this pump turned down 50% that a 1/2 pipe can't drain 250 gph (500 gph pump with about 4 ft head height). I turned the return down a little more and also adjusted the gate valve which was wide open down about 1 turn and let it run for a few mins. It started spitting out air bubbles galore, and within about another min was sucking water. So I opened the return back to 50%, waited a few mins and no change. I then decided to just open the return back to 100% to see what would happen, and now it seems all is good and the emergency is dry even with the return back to 100%, so the only thing I can think of, is when I upgraded my return plumbing and turned everything off, a big air bubble got stuck in the main drain or something, and that was causing it to back up or something IDK.

 

[NanoReefWanabe]

have you tried a power down scenario…i would assume you will get wet feet again…i is not that hard to red rill those holes to fit 3/4" bulkheads, i would do that myself…(i assume you drilled the tank as most 40's don't come drilled)

barring that i am sure your 1/2" drains will airlock again in no time. or be obstructed by slime coat/ saltwater life buildup etc and overflow the tank sooner or later.

 

[swk]

Did someone suggest the 1/2" drains, or did you decide that yourself?

Personally, I echo the person who mentioned re-drilling the holes for a larger bulkhead. On my 75 gal RR tank I use the 3/4 line for my full siphon and the 1" for my emergency with the return over the back. In my last 40B I used 1" for both drains.