Nice Cheap DIY Overflow

you understand very well.i am waiting some reviews from another colleagues on this forum.

thank you.

 

I joined the forum just to reply to this thread!

I built the PVC overflow about 6 months ago for my 125g tank out of 1" pipe.

First, you will not get anywhere near the flow that people claim. I get less than 300gph. I had wanted to use a mag 7 return pump, there's no way. The pump over ran the overflow in no time.

Second, this overflow worked great. At first.

It is now giving me more and more problems. I suspect it needs to be taken apart and cleaned, but there's no way to do it since I hard plumbed it in. If you use flex tube and can remove the tubing to be able to remove the overflow that would be a good thing. This is not an overflow you can easily clean in place.

It's loosing it's siphon periodically which is not a good thing. It just randomly looses siphon.

It is very prone to getting air bubbles trapped in it. If your water level drops and your return chamber gets low (ie- you don't have an auto top off yet) causing your return pump to spew micro bubbles you will have to reprime your overflow. If a powerhead gets crazy and spews a bunch of bubbles, you may loose siphon. If you have your hands in the tank making waves that cause the water to 'slop' over the over flow and force air into it, you may loose your siphon. I suspect if you have a lot of flow in the tank making the water turbulent this overflow would not work at all.

Mine isn't too noisy, but the flow is low because I had to resort to using a small powerhead to run it instead of using the mag 7 I'd wanted to use.

Overall, this overflow does work and it is cheap. I don't think it's a good long term solution though. With all the elbow joints there are so many angles that the flow is reduced (this was pointed out to me by someone with more engineering expertise than I have). It doesn't skim across a large surface area so it's not very good at removing any waste that rises to the top.

I can't imagine how large a pipe you'd have to use to get really good flow, but it would be obtrusive in the tank!

I'm now shopping for an overflow box to replace the PVC overflow.

Liz

 

This overflow sounds really great. I'm going to try it out soon! Thanks!

 

I changed mine a little. Have a look here

http://www.3reef.com/forums/i-made/diy-overflow-pipe-83252.html

 

i built the overflow out of 3/4 first and the flow rate was very slow so i changed it to 1" it suffices at about 300 gallon per hour for my 36 gallon, i think for anything bigger you should go with 1.5", they take up alot of space inside the aquarium and mine have failed three times, once sump got too low and micro air bubbles got in overflow, once a piece of bubble algea got disloged by an emerald crab, and once i got distracted while floating a new leather. i think any overflow can fail and while these seem very reliable, i decided, for my new tank, to drill and install an internal overflow.

 

I've built one of these for a very shallow paludarium and it's just plain barely working. I'm using 1/2" pipe because I need very low volume but I'm getting nary a trickle in the end. I've posted a video of it on YouTube.

Anyone have any suggestions? This is obviously not working as it is. Thanks!

-Mike

 

There ya go!

 

Your design is all off. It looks to me like you have the tee on the outside to high. Another problem is 1/2" pipe can't drain enough to begin with. I've built 2 of these, both from 3/4" and get at least 165-170/hr on both.

 

Ha, thanks, I fixed it before I saw you fixed it too

I'm assuming the slow flow is due to how close the T-connector is to the inlet. I had them so close as I recall something I read that said the outlet flow needs to be at the minimum height for the water. This means I have almost no pressure working in my favor but it still seems pretty pathetic.

-Mike

 

Wow, crazy fast response. My design is based on this:
DIY Overflow Using Only PVC Pipe (DIY OVERFLOW PROJECTS)

I dropped the T to be the minimum level of the water. If the T drops below the height of the lower bend, won't the siphon break and defeat the whole purpose if the power goes out?

As for flow, I need very little overall - 1/2" has an ID of .602 and 3/4" has one of .804 (schd. 40). So based on your numbers and a proper design, I'd expect to see at least 100 GPH which is more than enough for my needs. I need just enough flow so I can run a waterfall inside the tank into the small reservoir. The water is there primarily as runoff for the plants and to keep the humidity/temperature up. This overflow is just so I can get the water to an external sump where the filter and heater will go. Thanks!

Mike