afterthought bottomdrain

[vertigo72]

Hi all,

As some of you may have read, my 50.000 liter pond (made of reinforced concrete) emptied itself and im busy cleaning it.
Now I havent quite reached the bottom yet, so I cant post pictures, but going "by feel" there is a small pit at the bottom, 20-30cm diameter, 10-15cm high, that might be big enough to fit a bottomdrain. I even suspect it was made like that for this very reason. Below you see a rough cross section of the pond and what I have in mind:



I was thinking of putting a bottomdrain, assuming it will fit (think it will be tight), then adding a pipe up (what diameter do I need at least?), filling it up the rest with cement.

Red is the bottom drain (with a cap over it, or better not?), blue is the pipe, green the cement.

Any thoughts or tips? What about cleaning, it will be impossible to clean as its unreachable. Just pump water in the other direction?

 

[vertigo72]

Googling around, I came across this "vacuum bottom drain":

Sure would be easier to install. How different would it be from a "real" one?

 

[vertigo72]

More thinking... leaves will end up in there, and I think either approach will therefore fail. I dont think my pump can handle leaves (its rated for solids up to 8mm) so its gonna clog, no? How is that handled with a traditional bottom drain?

The solution would seem obvious, but apparently, either no one has thought of it, or no one seems to sell.. or its a bad idea. But I think whats needed is a underwater leave shredder! WHen I look at my wife's kitchen mixer, whatever you call the thing to make vegetable soup with. Thats what I need in there! Shop those leaves to mush and then pump them up.

Should I file for a patent lol, or what am I missing here?

 

[Malak]

Interesting thought experiment. Be cool to design a self-cleaning input filter. I'm sure that could be done somehow, but the leaves would stay until decomposed to a certain point where they would break-up into smaller pieces.
But I guess the way they normally work is that all the crap goes into a "settlement" chamber where the solids settle to the bottom and the "flow" keeps going. If you could have a totally removable system with this chamber is may be better than nothing.

 

[addy1]

Vertigo, a real bottom drain, pulls the water better. If you could fit one in the pit it would help you in keeping your pond clean, and like your design have the pipe come out into the pond. 3-4 inch pvc. I don't recall the filters you use, but from what I have read a settlement chamber would take care of junk pumped up out of the pond.

 

[vertigo72]

yeah I was reading up on settlement chambers, and I guess thats the proper solution. Well, you still need to clean that out once in a while, so barring a combined pump/shredder its the second best solution :bouncycig:

Problem is I dont intend to drill holes in this pond, so even if I dug a settlement chamber, Id need pipes over the edge, and I assume those ought to be big (therefore ugly) pipes and Id risk air getting in. Perhaps Ill do that anyway later and for now just put the pump at the bottom and be done with it. Anyone have a clue how thick such pipes ought to be ? Could I get away with 70mm? I might be able to camouflage that somewhat.

 

[vertigo72]

Interesting thought experiment. Be cool to design a self-cleaning input filter. I'm sure that could be done somehow, but the leaves would stay until decomposed to a certain point where they would break-up into smaller pieces.
But I guess the way they normally work is that all the crap goes into a "settlement" chamber where the solids settle to the bottom and the "flow" keeps going. If you could have a totally removable system with this chamber is may be better than nothing.

BTW, what I was thinking was to shred leaves and other debris inside the bottom drain housing, or even the pipe leading up to the pump, not a settlement chamber. the "pulp' would then be pumped to the mechanical and biological filters and be handled there. I guess that would put more strain on the filter, but done right, it could be almost zero maintenance (other than flushing the bottom drains of your filters once in a while).

Dont think its doable as a DIY project though. Seems a pretty tough thing to design unless someone finds me a waterproof kitchen robot :bouncycig:

 

[addy1]

I am not sure what sizes bottom drains come in, you could reduce down the size of the output pvc. going over the edge, you can paint, cover with rock on a roll, put rocks over it, etc there are ways to hide it. Since you have it empty if it is a pit for a drain, it would be good to do it. run the pipes up to the edge but not out of the pond until you are ready to do the next step, hook them up

 

[Malak]

If we can put a man on the moon, then anything is possible. You just need to creatively think outside of the box.

 

[vertigo72]

I decided against it. The point of a bottom drain is that gravity is your friend. If Im going to have to pump water and debris up over the pond edge before I can let it settle, gravity will no longer be my friend. Ill also have issues with air getting in there, starving the pump if I put the pump outside the pond, and if I put it inside, it will clog. In short, there isnt much advantage. Since I was also running out of time and had to move my fish in, I just put the pumps at the lowest point. For sure dirt will accumulate there, but then with the design of the pond, its never going to be a crystal clear and spotless "aquarium", and I can live with that.

 

[addy1]

Pumps at the lowest point help! Sweeping the bottom towards the pumps also helps if you can, do it off and on.

 

[Malak]

Addy has a point because the debris is not the problem directly, but rather all the polluted water that develops around the mush.