Herbie siphon question
1 - 13 of 13 Posts
Joined
·
206 Posts
Not sure if this is possible in your setup, but if you are able to plate a grate inside the overflow and above the elbow you could lay a filter pad flat across the entire overflow box.
I have two internal overflow boxes, 6-1/2 x 3, and I put filter pads on top of egg crate that sit on top of the pvc fittings. As Diana said, the trick is too not let them get too clogged or the level inside the tank rises and the level in the sump lowers. What I did to reduce this effect is to have one box slightly lower which takes more flow. As it clogs, the level rises and then the 2nd box now makes up the difference. When I see this, I wash them out and start over again. I use 3-stage pads and they last for 3 cleanings which averages 9 days. The fine filter pads in my ex canister would clog in the first days but would stay that way for 3 months, that is why I went to the sump in the first place.
Like I said, if you can get egg crate over the top of the internal fittings you can do that, even if the pad is higher than the weir, the water comes through the side of the pad just fine.
I have two internal overflow boxes, 6-1/2 x 3, and I put filter pads on top of egg crate that sit on top of the pvc fittings. As Diana said, the trick is too not let them get too clogged or the level inside the tank rises and the level in the sump lowers. What I did to reduce this effect is to have one box slightly lower which takes more flow. As it clogs, the level rises and then the 2nd box now makes up the difference. When I see this, I wash them out and start over again. I use 3-stage pads and they last for 3 cleanings which averages 9 days. The fine filter pads in my ex canister would clog in the first days but would stay that way for 3 months, that is why I went to the sump in the first place.
Like I said, if you can get egg crate over the top of the internal fittings you can do that, even if the pad is higher than the weir, the water comes through the side of the pad just fine.
Joined
·
134 Posts
So I can tell you from experience that anything that slows the flow (over time) is going to be a real pain in the butt. With my strainer cap on my siphon drain, every time a small piece of plant matter gets stuck in a strainer hole I feel like I have to adjust my gate valve, you can tell because the overflow starts gurgling, even when lots of holes are still clear. If I clean off the strainer than it quickly adjusts back to normal. I feel like a piece of sponge would be far worse. Could be wrong. I'd be interested to hear if it works out for you.
Joined
·
206 Posts
I have no idea what that means. Is the overflow internal or external?
Joined
·
1,461 Posts
I found the same, anything that slows the main drain calls for a gate adjustment. Mine is touchy between too much water in the box and not enough. But once dialed in as long as nothing slows the main drain flow it runs like a champ.
Joined
·
1,271 Posts
My tank has an acrylic cover over the whole top Euro style , with 2 rectangular opening in the middle and over the overflow , but it extends about a half an inch over the edge of the overflow . It is internal .
Bump:
Thanks for the info . I have plastic canvas on the inside of the teeth of the overflow box to keep fish out , so I am thinking this will catch any larger debris . Guess I will find out when I get it going...lol
While I am here.......do I have to run the water level just at the bottom of the teeth of the overflow or can I keep it about a 1/2 inch higher ? Sorry if these are newbie questions but I am a newbie to sumps and overflows .
it will depend on the flow through the teeth. Usually the water level will rise higher than the very bottom of the teeth, simply because all that water cannot get through a restricted area. But if there is a large tooted area then the water won't rise very high before it can all spill through between the teeth.
Example:
Lets say all the water would flow in an area of 1 square inch. If there were no teeth, and the weir was 8" long, the water would rise 1/8" as it flowed over the edge.
But now lets put teeth in there that block off half the flow. Instead of 8" with no teeth, the teeth now block off 4".
Now the water will rise to 1/4" high as it flows in the space between the teeth.
This is why certain of the fittings are not glued, but snug fit so you can adjust the flow.
Example:
Lets say all the water would flow in an area of 1 square inch. If there were no teeth, and the weir was 8" long, the water would rise 1/8" as it flowed over the edge.
But now lets put teeth in there that block off half the flow. Instead of 8" with no teeth, the teeth now block off 4".
Now the water will rise to 1/4" high as it flows in the space between the teeth.
This is why certain of the fittings are not glued, but snug fit so you can adjust the flow.
I use a semi-modified overflow box with a herbie-style setup. I don't have a U-bend in the main pipe, just an open pipe facing up that is low enough that it runs full with no gurgling (about 2.5" below water surface in my tank - this would change depending on flow). I have a foam tube around it that extends above the waterline. As the foam gets clogged, the waterline in the back box raises a bit, this increases the pressure and the area available for the water to pass through the foam. It really doesn't take much of a waterline change for the flow to even out. The foam tube is the only thing in my filter system that I clean every week - it gets all kinds of plant matter and other junk on it . . . works great!
-Justin
-Justin
1 - 13 of 13 Posts
Join the discussion
