Caping My Overflow With Gravel ?

[nicky1200]

So i have a overflow built into the center of my tank and installed 2 bulkheads by hand to the overflow. I fill up the overflow and have noticed the one is leaking very badly so i have googled around and worked out that i put the bulkhead on the wrong way ( the nut is on the inside ) so i have tried to undo the overflows to put them on the right way but they are two tight. The one which is leaking when you turn the nut the whole bulkhead turns i have asked a friend to hold the bulkhead from the bottom while i try and undo the nut but still not luck. I have even had a builder in to try and undo the nut with no luck. So now that i understand that its not gonna come off i need a way to stop it from leaking. I have tried to silcone around the bulkhead and around the glass but this does not work. I have asked the builder and my local petshop and have been told that i can cap the bulkheads with gravel which will fix it.So i have 2 pipes going into the bulkhead and if i put gravel from the bottom off the over flow to the top of the pipes the water will not be able to grow though the gravel.
I have just tried this with sand and is still leaking.... I have around about 12 inch from bottom of my overflow to the top of the inlet pipe in my overflow I have filled it up about 5 inch with sand but the water seems to be going though the sand...
 
So would gravel or sand be better to cap the over flow with ? And is this the way to go forward ?
 
I am guessing that the sand would be better to cap with because of the smallness ?

 

[DrRob]

If there is a hole, water will go through it. Covering it with stuff that has holes in it (like a sand or gravel bed) will not stop it, the hole must be sealed.
 
I suspect that they're hoping that the weight of the substrate will push the leaking joint together to stop it. Sadly it's unlikely to work with a fair amount of head of water above it.
 
You options are to seal the whole or to get that bulkhead out and start again.

 

[nicky1200]

If there is a hole, water will go through it. Covering it with stuff that has holes in it (like a sand or gravel bed) will not stop it, the hole must be sealed.
 
I suspect that they're hoping that the weight of the substrate will push the leaking joint together to stop it. Sadly it's unlikely to work with a fair amount of head of water above it.
 
You options are to seal the whole or to get that bulkhead out and start again.

The bulkhead will not come out i would have to burn the bulkhead out i think. I have filled the overflow up half way with sand and the leak slows down....  I was thinking if i fill it up the whole way maybe it will stop..
So the water will go though 12 inch of sand im guessing ?
Im thinking if i make a deep enough bed of something the the water will not go thought it
 
Also if water can go though sand then why do they use sand in sandbags to stop water going into your home when there are floods ?

 

[DrRob]

They use sandbags to slow the flow down, problem is, once the water gets through the sandbag it carries on regardless, particularly when there's a head of water, as the water at the bottom is under pressure from the column above. So sandbags only really work for flash flooding that settles quickly (ask anyone who's tried them in a sustained flood). Sandbags are also good for deflecting the pressure of flowing water and the damage that that can cause.
 
If you make it deep enough it'll put more weight on the joint, which may slow it down more, but it's unlikely to stop it unless it slows it enough to start to seal the hole with scale from evaporation (think stalactites or the scale line we get on half filled tanks).
 
Other question, can you seal the top if you're not going to use it, or is the other outlet in use?
 
There's also the issue of this becoming a large anaerobic area in your tank.

 

[nicky1200]

They use sandbags to slow the flow down, problem is, once the water gets through the sandbag it carries on regardless, particularly when there's a head of water, as the water at the bottom is under pressure from the column above. So sandbags only really work for flash flooding that settles quickly (ask anyone who's tried them in a sustained flood). Sandbags are also good for deflecting the pressure of flowing water and the damage that that can cause.
 
If you make it deep enough it'll put more weight on the joint, which may slow it down more, but it's unlikely to stop it unless it slows it enough to start to seal the hole with scale from evaporation (think stalactites or the scale line we get on half filled tanks).
 
Other question, can you seal the top if you're not going to use it, or is the other outlet in use?
 
There's also the issue of this becoming a large anaerobic area in your tank.

 
 
I have silconed the whole of the inside of the bulkhead ( around the nuts ) I left it 48 hours but still leaked though....
I have a inbuilt overflow in the center of my tank with 2 holes in the middle of.
 

 
There is a screen shot of what i mean. I have 2 bulkheads with the screen on the inside ( like the left one which you can see ) I then have a pvc pipe which goes into the bulkhead i then have tried to fill in the middle bulkhead up half way with sand.
 
 
Here is a pic of what i have. The left pipe is the inlet and the right pipe is the outlet