Why an overflow?

[Anonymous]

I made a complete box for 2 reasons really

1. Because this is an existing tank and I can't really drain it all the way down to silicone an over flow in, and this "underflow" had to go most of the way to the bottom

2. Because this was really only a test, I really still don't know if I will like the final results. If I don't end up liking it, all I have to do to change back is take the lights and cover off the tank, pull it off and stick the old drain piece back in place. All of 3 minutes work.

 

[Anonymous]

Oh, there is another reason I forgot about.

I am going to be getting a 45 gallon tank for a sump to use in the basement, and I am most likely not going to be able to use this knuckleflow at all then because I am pretty sure my current return pump is not powerfull enough to push the water that high. And the only other pump I have (an Iwaki 30) is way too much flow for just one drain, I will have to have an overflow that utilizes both of my drains then.


I already have the design for a new one in my head....

 

[Anonymous]

Last night I set a powerhead in the tank on a wave timer, I thought I had it adjusted right.

This morning I wake up to milky water and very P.O'd creatures.

The knuckleflow filled up with sand at the bottom, but the water just rose a 1/4 inch in the main tank and flowed over the top of my overflow thing. It still drained to the sump all right. Not a drop of water on the floor or anything.

All straightened out now, all I had to do was push the big pile of sand the powerhead pushed in front of the lower suction holes out of the way and it sucked the sand that was actually inside itself right up.

 

[Anonymous]

Well

A couple days have passed with no changes by me, and my skimmer seems to be working just as well as it did before I put this on.

Also, there really is no surface scum collecting on the surface, I think my circulation is keeping it mixed up....


After about a month or so I will give another update on this.

 

[Anonymous]

have you felt along the bottom to see if there's much of an incoming "suction" ??

 

[Anonymous]

No, but if you want I can take a video of it sucking up a bit of algae or something, and you can see large sand particles going up and then falling, the lighter stuff goes on up.

If I stir the sand right next to it, it sucks it up and then down to the sump...

 

[Anonymous]

Alright

An update


Its working very well, its keeping most of the junk off the sand, I can actually watch it get dragged back and sucked back up the knuckleflow.

But, there is a skim at the surface, its not a lot, but its enough to annoy me.


the solution? cut a small slot at the top for water to come from. Any I take from the top will reduce the amount of suction from the bottom though, and I am not sure I will be happy with that.


As soon as I figure out how to cut it without taking it out of the tank I will cut it.

Probably sometime this weekend, and then I will let it run for a couple weeks before giving another update

 

[Anonymous]

Well, I have to update now.


I cut the slot around 2pm today.


Its now 5:50 pm and I declare the surface of the water clean and clear again.


The slot is about 3/8" to 1/4" wide and only 1/8" below the surface of the water, but because of its location as the water goes around the top in a circle, which is what I have my circulation doing, it pulls the gunk right in.


Awesome!


Here is a blurry pic....

 

[Anonymous]

I think that this is a great thing to use on a bare bottom tank, in that case I would make the contraption go right to the bottom, and the slot would be at the very bottom, right next to the glass.

because I balanced the flow that goes through it with my pump, I get a nice suction -- no its not enough to feel if you put your hand in front of it, but if you dribble some sand or gunk near it you can watch it go right over and up....


Making one with tons of slots at the bottom would make it so all the slop just gathers around it instead of getting swept up.


Do you understand what I am saying?