How to plumb a bottom drain to a negative edge cistern?

[combatwombat]

I don't think I'm going to do this, but maybe you all can help me think through how I would go about it if I did.

Bottom of pond will have gravel in it. Skimmer will be a negative edge waterfall into a cistern. Pumps will likely be submersible pumps housed inside this cistern.

Now, how would you go about plumbing a bottom drain into this scenario if you wanted to?

The gravel on top of the cistern is the prefilter, so you would want the water from the bottom drain going through it before it gets to the pump(s) below.

I'm really not sure how you could set this up. Maybe you'd have to wall off part of the cistern to become a gravity flow settling chamber? I can't really see how you could combine these two concepts. Perhaps they would have to live separately.

 

[combatwombat]

Nevermind, I think I figured it out. Just had to ponder it for a minute.

 

[GBBUDD]

I have mentioned this several times and I know it was on at least one of you posts. Like your self I contemplated debris getting into the cistern and creating sediment and waste build up. @Lisak1 Her misfortune became my inspiration. Someone had told her to cover the cistern with non woven fabric to help filter. She then said it didn't take long for that to clog and fail. So that gave me the idea of like a chimney that has a clean out. The water comes down the side of the cistern instead of the top the water drops into a removable and disposable bag I made out of Non Woven fabric. So as this clogs up the top of this bag is even with tge top of the matrix in the cistern and then flows through the rocks like a standard negative edge dropping through the rock but this weeps in from the sides. No build up in the cistern no filling up the valuable space.

Negative edge with a twist before it enters the cistern

nam12.safelinks.protection.outlook.com

 

[GBBUDD]

I thought. you were leaning toward the intake bay ?

 

[combatwombat]

I remember that detail, @GBBUDD.

I was planning an intake bay, but now I am older and wiser and found a good opportunity to implement a negative edge.

I was more trying to figure out how to add a gravity sieve or settling chamber in the same space as the cistern and getting the plumbing from the drain into it in a gravity fed manner (i.e. pipe work can’t go above water level).

But then I realized there are several good ways to do that, and it’s not really necessary to have the sieve or settling chamber in the same place.

 

[combatwombat]

I could also skip the sieve and just pull directly from a pump, which would make the impeller chip everything to bits before sending it on.

Think that’s frowned on in the koi keeping community, but... ‍

 

[GBBUDD]

The sieve is basicly what I made with the shits creek in the video. Instead of the entire flow falling into the cistern I only alow a small pump to work the cistern after all the cistern is to store and have water available. To keep the water cooler in the summer. It also limits how much gets to the cistern. . Because what I forgot to mention in the video was I draw from shits creek with the main pump , as well as pulling from the main drain in the main pond. Again using life lessons. I have seen where so many realy find cleaning the debris from the rocks ontop of the cistern a real challange . So instead is the water area much easier to clean.

 

[combatwombat]

Where is your main drain plumbed to? Skimmer box?

 

[GBBUDD]

Main drain goes straight to the external pumps basket early spring it needs weekly cleaning from the winter algaes

 

[GBBUDD]

Still planning a patio/ fire pit on top of the cistern ? I guess I didn't show that real well there's a foot of fill on the top of my cistern a fire pit could easily be placed there . One thing I did do was to wrap and seam the top of the cistern with the epdm. and place azek 1/2 inch sheets ontop of the matrix blocks before I placed the foot of fill ontop of it. The area with the opening just had the liner not sealed at the top there

 

[GBBUDD]

Well at least your drawing neer to the end of planning you can't go to much further. The build will start and you'll geter done

 

[combatwombat]

Thanks for the extra details, @GBBUDD. What was the purpose of the composite sheets over the matrix blocks?

I know folks are getting impatient with my lack of progress and wandering off in different directions with my build. But that's just how I operate! We're at the point of no return for a few important decisions, so I want to make sure I don't lock in any compromises I don't have to.

And the further I get into this project, the more confident I get about taking on some construction details that I didn't think were even possible when I started.

 

[brokensword]

I definitely hear a stall, here...or minimally, a distraction. Does your wife know about this further change???????

 

[combatwombat]

I definitely hear a stall, here...or minimally, a distraction. Does your wife know about this further change???????

She knows and is on board now. I sold it well. Also, she knows how I operate and that, when my projects are done, they were worth waiting for. Still wouldn't mind me working a bit faster...

 

[GBBUDD]

Thanks for the extra details, @GBBUDD. What was the purpose of the composite sheets over the matrix blocks?

I know folks are getting impatient with my lack of progress and wandering off in different directions with my build. But that's just how I operate! We're at the point of no return for a few important decisions, so I want to make sure I don't lock in any compromises I don't have to.

And the further I get into this project, the more confident I get about taking on some construction details that I didn't think were even possible when I started.

Don't worry about others your doing exactly what we preach do your home work now. Even if you get turned around a couple times. It's your build your oasis, your back, building it right wrong or indifferent it's YOURS. you'll get there in your own time.
The composite sheets were to insure nothing punctured the rubber on top and the sand /soils did hour glass into the cistern plus the matrix blocks felt like they could use some structural help. WITH A FOOT of soil on top that's a good deal of weight. I have seen since I built mine . What I did that with the azek that aquascapes is now selling what looks like a large pannel of the aquablocks that it is doubled. I belive it was for the extra support on top and also to catch as much large debris as possible.