DIY overflow - tank either drains out, or overflows

[TheWolfman]

Also if this was happening wouldn’t it back up and drain then the drip catch up and the cycle repeat?

It’s not a matter of how much water is entering the tank. The overflow will only flow so much before the tank starts to flood. The water needs to be able to escape the drain in the overflow without being slowed down or the overflow will back up and the overflow will go full syphon and loose prime.

 

[mattybecks]

Yeah man I don't trust those versions of overflows at all. That's why I just did a easy water change system instead of a drip for so long. Now the sump is drilled to facilitate a drip system so will see once I get it all up and running again.

I am thinking along the same lines as you then. Next time I get an aquarium made, I will have it pre drilled. For now I am actually quite happy with this and the simplicity and ease of water changes now.

 

[mattybecks]

@mattybecks
I noticed that In the original picture the overflow is up off the rim. This little bit of extra hight could be affecting the water level in the aquarium. The water would raise higher in the tank before it drains.
Is this for a reason?
or could this have been you problem
View attachment 1403905

this was just as I put it in the tank, hadn't been connected up yet. Just took a photo quick to show you guys, it was resting the rocks below, but I removed those so it did dip lower in the aquarium when I was testing. I played with the level after that.

 

[mattybecks]

this I how I held the overflow up just two zip ties the first zip tie goes through a hole in the overflow and is used to set the water level in the aquarium. The second is to hold the first one in place. I think the major flaw in your first design is the fact that the drain downsizes when you coverted to hose. When the water gets to this spot it backs up and then goes full syphon and is braking the syphon in your overflow. Then the tank floods. If you upsize the hose and pvc here you should be good. View attachment 1403910

Ahh interesting. Thanks for the pic and explanation. I didn't think the reduction in size would have played such a major role, but I can see now how it would.

 

[mattybecks]

I agree for a drip it should be fine, In Op he said he’s using it as a flow through rather then a drip. I’m assuming that the water can’t get out the drain of the overflow fast enough. I also agree that lowering the hose would help. It shouldn’t be a elbow at all.

Another point I didn't realize. No elbow joint connecting the tube to the overflow.

 

[mattybecks]

I assume what he meant by flow through was that the drip was constant and the overflow should constantly drain this away.

Yes I did, sorry if I was not clear and caused confusion. I was posting while I was working on this and struggling haha. I was testing it both ways, adjusting the rate of flow going from drip to faster flow. Just to see. Still had the same problem both ways.