Overflow Problem...

[Sir Alex]

So, I got a used tank off of craigslist and I've been fixing it up. I redid some of the piping and got a new pump. I also changed the sump to a smaller one.

So today I ran a test fill. Everything went okay, but the overflow box is giving me a fit. It can't keep up with the pump unless I almost close it all the way. But then it's hardly circulating. So this is what happens when the valve is all the way open:


[ame="http://www.youtube.com/watch?v=ypFjMZnMNgk"]‪Oveflow Problem...‬‏ - YouTube[/ame]

 

[irensing]

well I can't view youtube since it's blocked in the office (we have IT nazi's), so without seeing it my guess is your plumbing lines are too thin/long or your overflow box is not large enough. If the over flow box is emptying then you can probably rule out the plumbing and vice versa.

 

[irensing]

a valid test might be to put the plumbing directly in the tank (without the box) and then tweak the valve. This would probably give you an idea how much your plumbing alone is contributing to the issue.

 

[Sir Alex]

If the over flow box is emptying then you can probably rule out the plumbing and vice versa.

The water is going out of the overflow box faster than it's coming in, so it keeps emptying.

Should I get a better overflow box?

 

[irensing]

The best solution would be a better or larger overflow box, however, and keep in mind I haven't seen what you're using, you could probably cut away some of the barriers to make larger slots for the water to flow into the box faster. Before doing so, you have the box set pretty well in the water right? in other words you're giving the water the best chance at getting in the box at max rate? ultimately your overflow box depth would control your water line height.

 

[Sir Alex]

The best solution would be a better or larger overflow box, however, and keep in mind I haven't seen what you're using, you could probably cut away some of the barriers to make larger slots for the water to flow into the box faster. Before doing so, you have the box set pretty well in the water right? in other words you're giving the water the best chance at getting in the box at max rate? ultimately your overflow box depth would control your water line height.

Err, I'm not exactly sure what you're saying. Just tell me what you think when you get home.

 

[irensing]

LOL! let me look at it on my cell phone.

 

[irensing]

ok, let's say the slots in between the barriers are 0.25". Water can only flow at a certain rate through 0.25". If you cut some the bariers to effectively make the gap where the water flows 0.5" than it will fill the over flow box faster. However, having a large gap isn't necessarily a good thing if you are worried about a creature in your tank being sucked in. Does that make sense? If you want to have small slots than you need more of them to allow more water in.

 

[irensing]

looking at the video it looks like the box is clearing real quick. Are you sure even with it turned down that it's not circulating enough? What size tank is it?

 

[Sir Alex]

I looked to see how big the cracks would be if I cut some off. It's big enough to suck and small fish...

looking at the video it looks like the box is clearing real quick. Are you sure even with it turned down that it's not circulating enough? What size tank is it?

I have the MD12 pump which should be going in to the tank at about 850 GPH. To get the overflow to stop emptying I have to turn the valve probable 75 degrees out of 90. It feels really weak coming out like that.



Another question. What size tubing should I be using on the pump? It says the output is 3/4". I have some 1" tubing which fit right on the MD7 (1/2"). Does that mean 1-1/4" tubing should work?

 

[irensing]

I'd consider a larger overflow box (more slots, longer/wider). as for the output hose 1-1/4" sound like it would work based on your experience with the MD7. keep in mind the larger the diameter the harder it is to push the water up vertically.

 

[Sir Alex]

I'd consider a larger overflow box (more slots, longer/wider). as for the output hose 1-1/4" sound like it would work based on your experience with the MD7. keep in mind the larger the diameter the harder it is to push the water up vertically.

The tank came with a broken MD7.

Know a good overflow box? All the ones I could find are HOB.

Something else I was considering was selling the tank, and buying a new one with a corner overflow. But then I would have to redo the plumbing. :shock::shock::shock:

 

[irensing]

not really sure, maybe you could try 2 of the HOBs in parallel and if it doesn't work bring it back??? built in corner flow would be better. I have a 120g dual corner flo sitting in the garage, but prolly gonna sell it.

 

[Sir Alex]

I have a 120g dual corner flo sitting in the garage, but prolly gonna sell it.

Aren't corner overflows built in to the tank?

 

[irensing]

i just googled this. there is an 800gph dual output overflow Aquarium Filters, Wet/Dry Filtration and Overflow Boxes.

 

[irensing]

yes cornerflows are built in and then have drilled holes in the tank bottom for plumbing

 

[Sir Alex]

i just googled this. there is an 800gph dual output overflow Aquarium Filters, Wet/Dry Filtration and Overflow Boxes.

Why do they have two pipes coming out of the bottom?

 

[Sir Alex]

With HOB overflows does the siphon need to be started manually or does it start by its self like an in tank one?

 

[irensing]

I can't be certain about the 2 pipes but it is probably to maintain 800gph. the HOB probably needs a manual kick start but shouldn't lose the syphon until you have to clean it or whatever.

 

[Sir Alex]

I can't be certain about the 2 pipes but it is probably to maintain 800gph. the HOB probably needs a manual kick start but shouldn't lose the syphon until you have to clean it or whatever.

How do I start the siphon? Do I suck on it?

How's this one? PF-800