Plumbing sizes and fittings

[redracer77]

I am getting more sorted with my new tank and want some advice on plumbing sizes for the drains and returns.

Tank will be approx 650L with an 80L sump.

I was thinking 32mm plumbing, does that sound right for that size tank?

should I use the same size for drain and return?

Where is a good place to get fittings from? I want reasonable quality

Should I use pvc pipe or will flexible tubing do the job fine?

Thanks

[David R]

The size of the drains needed will depend on the amount of flow you have, not the size of the tank.

Here's a useful link for this sorta thing; http://www.monsterfishkeepers.com/forum ... Flow-Rates

I'd be inclined to go with at least one 40mm drain for a tank that size, especially if you're just going for a traditional single-drain set up (not a herbie/bean animal tyle multi-drain system), it's always good to have redundancy with that sort of thing. Depending on your pump size you could probably use 25mm, but no harm in going 32mm and it will probably work out cheaper as you can use PVC waste fittings instead of the more expensive pressure pipe ones. I use the RXPlastics bulkheads and Marley PVC waste pipe for the rest with returns and drains. Cheap, easy to cut, glue and drill, can be painted with Krylon Fusion spraypaint if you want the returns to look a bit less obvious in the tank.

[Ira]

The size of the tank isn't really the deciding factor, how much are you planning to flow through the piping? But, regardless 32mm should be heaps for any reasonable amount of flow. My tank that had an overflow was running about 4000LPH through 25mm and that was a bit borderline.

You can have the return and drain the same size, or the drain bigger. That one needs to be bigger because it's not being force fed.

[David R]

My tank that had an overflow was running about 4000LPH through 25mm and that was a bit borderline.

According to the numbers in the link I posted the maximum gravitational flow of 25mm pipe is around 2300LPH, how sure are you that the pump was actually pushing 4000LPH? What diameter was your return pipe?

I've found those numbers to be quite accurate and from what I've read others have too. With my current set up, one of the 50mm drains will handle the flow of about 8-8500LPH (which is a conservative estimate of what the pump should be running) at a full siphon, with less than the "minimum vertical length" required to achieve the max flow for that diameter pipe (~9100LPH). If you've got 600L of water in your tank and you want to turn it over five times an hour you'll want to have a pump capable of moving 3000LPH of water at the required head height. A single 32mm drain running at full siphon should flow up to 3500LPH, so would be adequate. A 40mm drain will flow more like 5000LPH, so would certainly give you more of a safety factor.

[hovmoller]

redracer77 I will give you my specs for comparison:

800L tank

90L sump I think

5000lph return pump (I estimate it delivers 3-4000L at my tanks height)

I run 25mm return line and two 25mm drains (one going full syphon and one only small trickle (herbie overflow))

I use Hansen fittings for everything because I just love them so much and 25mm clear pvc tubing.

It runs very well and I wouldn't do anything different if I could.

[redracer77]

I have been looking at the mfk post, I am going to be running 2 drains, 1 at full syphon

I don't have a return pump yet, but looking at something around 4500lph so realistically pumping ~3000lph

I will go 32mm which was my first thought.

Thanks Hovmoller, I have been looking at Hansen fittings, do you use the push on fittings with hose clamps?

[Ira]

According to the numbers in the link I posted the maximum gravitational flow of 25mm pipe is around 2300LPH, how sure are you that the pump was actually pushing 4000LPH?

Bucket under the return, Volume*time=rate plus round it up. It was more like 3500 iirc.

What diameter was your return pipe?

The return was 25mm or 32mm clear hose halfway to match the outlet on a PJ5000, 25mm the rest of the way.

The siphon and bubbling was annoyingly loud, but it handled the whole flow of the pump.

[hovmoller]

Thanks Hovmoller, I have been looking at Hansen fittings, do you use the push on fittings with hose clamps?

No I use the easy fit fittings with the pvc hose combined with threaded fittings. Like this: