External overflow drain tube length?

[Cox]

I posted this in the filtration forum but haven't gotten any input and I'm trying to get this hooked up ASAP.
I am about to add an external overflow along with a sump to my 20 gal. I got an eshopps overflow that didn't come with any pvc tubing attached to the bulkhead. I cut some 1" pvc for the drain tube and was wondering if I have it too short or too long? As you can see in the pic, the overflow is the type that has 2 chambers, 1 where the u-tube goes into and 1 that it overflows into and has the drain tube. Can anyone tell if this is OK or should I change the length? Thanks.

 

[Hal]

It's probably a little on the short side, unless you plan to add a durso or stockman.

The water that flows into the right side in the pic from your U tube will fill that chamber, then overflow the wall into the left chamber. The water will then fall until it reaches the water level of the left side chamber. With the PVC pipe as low as it is, the water could fall some distance, resulting in NOISE.

I usually try to get the point that the water flows into the bulkhead tube (the pvc coupled to the bulkhead) just below the height of the wall dividing the chambers. Again, a durso or stockman mod will add height to your setup shown. If not using them, I'd add a little height to the pipe.

You could also run the system as is and see what happens. The waterlevel in the left chamber might be quite high normally depending on your flowrate, for example.

Lastly, adding height to the left side pipe shouldn't affect flow rate. Your flow rate will likely be more limited by the flow rate of the siphon to get the water into the right side chamber. At least it is in my experience.

Hope this helps.

 

[mille239]

why is the pvc on the bottom of the overflow sharpened like a pencil? LOL

 

[Cox]

Thanks Hal! Yes, it does help me tremendously.

mille239, it's a trick I stole from someone else and it makes it soooo much easier to get the tubing on there.

 

[ste6168]

<a href=showthread.php?s=&postid=7222334#post7222334 target=_blank>Originally posted</a> by Cox
Thanks Hal! Yes, it does help me tremendously.

mille239, it's a trick I stole from someone else and it makes it soooo much easier to get the tubing on there.

so, your just going to get vinyl tubing and run it stright from the pvc with a clamp or something? thats pretty interesting, dont know if ive ever seen it done.

 

[Cox]

<a href=showthread.php?s=&postid=7222639#post7222639 target=_blank>Originally posted</a> by ste6168
so, your just going to get vinyl tubing and run it stright from the pvc with a clamp or something? thats pretty interesting, dont know if ive ever seen it done.

No, I'm actually using the ribbed tubing made specifically for the overflows (the ones with the collars built into the ribbed tubing that come in 4 ft lenghts) but I've found that it's much easier to get them on if you 'sharpen' the end of the PVC since it's really tight going on, even when soaking the collar in hot water.

BTW, I have seen some with just want you're thinking.