bulkhead connection advice

[oblio]

Bear with me here: Ive had this 90 gallon oceanic corner drilled tank for about 5 years. It uses a store bought durso that you can adjust the return level. This system has been running well enough for the past 5 years, for the last 2 months it seems the water level in the display is fluctuating enough that the water sometimes just touches the cross brace. I scrubbed the weir's and removed the flexible drain to see if something was preventing the water from returning. I noticed that the previous owner had glued a barbed connection INSIDE the return bulkhead (as seen from under the tank). This would reduce the returns capability. The way my sump is set up the drain is a dead shot straight down from the tank. What I want to do is find "something" that will thread onto the external threads of the bulkhead that I can then add a piece of rigid pvc pipe too. By using the external threads I would not be adding a restriction to the system. And by using the threads as the attachment mechanism it would be removable if need be.
Is there someone out there that sells a coupler that has the internal threads of the bulkheads and allows attachment to regular pvc?
Obviously i have been to HD and Lowes looking, nothing fits.

 

[ichthyman]

Although a good idea, there is no commercially available fitting that threads onto the exterior of a bulkhead. Because no two manufacturer's bulkheads are exactly the same, different sizes and thread counts, it is unlikely a universal fitting will ever be produced. Either a standardize size system and thread count will need to be developed/adopted or each company would need to come out with their own matching adapters. At ~$50k for each injection mold matching each size bulkhead, I doubt that anyone feels there is enough demand for them to make back their money much less making a profit on such a product. In the past, during the i-Tech era, I designed and machined the fitting you are describing but because of the fabrication cost making them "manually" one at a time they are simply too expensive for the hobby market. Perhaps if you're friendly with an experienced machinist and have access to solid PVC bar-stock you could "D.I.Y." what you need.

 

[CrazyEyes]

Why the outside threads? Why not just use a slip x thread bulkhead and use the inside threads? I know it might restrict it a tiny bit but that's probably the only option.

 

[asbauto]

I used thin wall pvc for my drains that is available at big home improvement stores and it seems to flow a little better due to the inside diameter is larger than sch 40. I added unions to make disassembly easier

 

[Ted_C]

one thing you'll notice (if you haven't already) - even with threaded fittings - nothing is easily removable. The only way to make things easily removable without cutting or tearing down the entire system is the generous application of unions or true union gate valves. That's really the only easy way to make things removable. If your looking for true union gate valves - I've found the lowes at the corner of 19 and 580 to be my best source (unless you order online).

So my suggestion is a total replacement of your existing bulkhead that has the glued connections with threaded bulkheads. use rectoseal and be generous with it on the internal threads. It's a non-hardening pipe thread sealant.

Like the ichtyman says - the only good way to attach plumbing to the bulkhead is the internal threads - never the external.

there is no further restrictions or added friction to waterflow when using the internal; threads on a bulkhead - as the width of the pipe is your restriction already. The threads on the pipe dont restrict your flow - as it's on the outside of the pipe.

For additional fittings to get your job done - abandon the trips to Home depot / lowes. Try an ace hardware instead - they usually have more pvc connectors of more exotic types. I recommend the ace in Dunedin on 580 or the ace in largo (hammerheads). I.e. need a street 90 that's threaded / slip? Ace will have it while Home Depot / Lowes may not.

Make a mental diagram of how you see the connections being made and make a plumbing list of what you'll need to make that happen.