Matching overflow and sump pump.

[karot]

Hello all,
I got all of my equipment yesterday and set up my 16g tank, so far 3 pounds of live rock and 20 pounds of Tahitian Black Sand with a small jet for a current.
10 Gallon sump with a 20 gallon Aqueon Power Filter(rated at 250 ghp), two 50w heaters and an AquaClear pump rated at 150 gph.
My problem is my pvc made overflow seems to not be matching with the pump. I know they will most likely never be spot on but I cannot even get them close! I have zip ties around the pump from the sump trying to slow it down but to no avail.
Does anybody have any suggestions or words of advice to fix this problem? Luckily it has not over flowed yet but has gotten close a few times.
Link to the set up is below.
Link
*Also the sump will be separated into sections in a few days, need to get glass cut and get some activated carbon for filtering. So some of the sand from the show tank will be removed.
-Karot

 

[number1gsxxr]

I think you are going about it wrong. You don't want to try to get the overflow and pump to be equal. You want the overflow to always be able to flow more water than the pump can pump. That way it will only siphon as fast as your pump can pump the water up to the tank.

 

[chrisnif]

From the looks of your picture your overflow is the PVC U kind of like I've got. I'm running 3/4" PVC and my return pump is 300 gph and I think i've got it pretty much dead on as my water stays above the overflow by an inch but doesn't rise any further.
From the "T" on your overflow it looks like you switch over to vinyl tubing, what size is that? I'm running solid PVC to my sump as it flows better.
Also I see the water level in your sump is very high, do some fake power failures to make sure you don't overflow if your pump turns off.
You're overflow doesnt look like it has any way to maintain a siphon if power fails either. There is a thread on another forum trhee reef that shows a good PVC overflow design (that I'm using as well).
Best luck to you.

 

[karot]

Then will that not eventually leave the sump to overflow? If the overflow is siphoning say, completely made up numbers, 5gph and the pump is pumping 4gph then that extra gallon will add up and overflow the tank.
Edit* I am running 1/2" pvc until it switches to 7/16" vinyl. It maintains a siphon from a air shut off valve that I took from my old pump for my freshwater tank. The overflow is completely electronic less. I will tweak my water levels to that if my pump shuts off the overflow will eventually run lower then the suction part of my overflow. If that makes sense.
Now that I look at it, my sumps water levels are really high. It is as full as my freshwater 10g which is most likely the problem.

 

[number1gsxxr]

I don't fully undertand your type of overflow but usually they can only siphon down to the water level in the tank. If that water level is dependent upon the return pump then it can't siphon more. It's hard to explain but I hope I made sense.

 

[karot]

It made sense. I think I have answered my own question with some thinking and the knowledge of my sump tank having too much water.
I will keep an eye on it for the next few hours.
Will keep the thread updated.
*Edit
I had to cut the smaller of the overflow tubes shorter. By the time the water level get below the opening of the smaller tube the siphon is lost and it gives my pump time to catch up, once caught up the siphon picks up again and all is good.
Problem fixed. Thank you everyone.

 

[beaslbob]

Originally Posted by Karot
http:///forum/post/3199993
It made sense. I think I have answered my own question with some thinking and the knowledge of my sump tank having too much water.
I will keep an eye on it for the next few hours.
Will keep the thread updated.
*Edit
I had to cut the smaller of the overflow tubes shorter. By the time the water level get below the opening of the smaller tube the siphon is lost and it gives my pump time to catch up, once caught up the siphon picks up again and all is good.
Problem fixed. Thank you everyone.
Hold on. If I understand what you are saying please study this overflow

(Just above section 3 is a small hole to allow air in.)
Does you design have a section 3?
At 3 the water in the pvc rises then "overflows" internal to the pipe. So that a constant flow is maintained with no breaking of siphon.
my .02

 

[jstdv8]

if you leave enough room in your sump for your tank to empty completey into it down to the overflow box setting then you are safe that way. then the nly thing taht can go wrong is you loose siphon and the pump overflows your tank. so if you put a float shut off switch at the water level that you consider your lowest and connect that to your sump pump(return pump) then if you loose siphon you will be safe either way.

 

[number1gsxxr]

Originally Posted by Karot
http:///forum/post/3199993
It made sense. I think I have answered my own question with some thinking and the knowledge of my sump tank having too much water.
I will keep an eye on it for the next few hours.
Will keep the thread updated.
*Edit
I had to cut the smaller of the overflow tubes shorter. By the time the water level get below the opening of the smaller tube the siphon is lost and it gives my pump time to catch up, once caught up the siphon picks up again and all is good.
Problem fixed. Thank you everyone.
It sounds like by cutting the tube shorter you did the same thing as a siphon break. A small hole drilled in the pvc below the waterline so that when the power goes out it will break the siphon when it starts sucking air.