HowTo Pipe 2 Cistersn together?

Let me repeat for emphasis.

If you have to dig a hole for tank #3, connecting them at the bottom involves no extra digging.

If you have a straight connection from #2 to #3 at the bottom, there is no siphoning action necessary, and pretty much nothing can go wrong except if the pipe fails. But that is about the same odds as a hole appearing in the bottom of your tanks.

What you are proposing is to make a more complex system, which is more likely to have something go screwy, located closer to the surface for easy access when it goes screwy.

Sometimes simple is best.

Most tasks that are worthwhile have some work involved to get maximum use and minimum headache.

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Agmantoo
If they can do it,
you know you can!

siphons will fail when you don;t want them to...connect #3's bottom to the bottom of #2 and as #2 fills, it will also fill #3.

As #2 is pumped out, #3 will also drop to the same level feeding back into #2 via the one bottom connection. I'd build a manhole between the two tanks so you can monitor the connection for leakage.

You won't need to change the system that feeds the house, only make a Siamese connection between #2 & #3...

Place tank three above tank two. Pump water from Tank 1 into tank 3. Install a PVC pipe from about 2 or 3 inches from the bottom of tank 3 up through the side of the tank several inches from the top. Run the pipe over to tank 2 and install a 90 degree elbow and then a PVC pipe into tank 2 (through the top) to whatever depth you want. (The bottom of the PVC in tank 2 must be lower than the bottom of the pipe in tank 3.) Use the water from tank 2 for the house.

How it works: Tank 1 fills slowly from the spring. The water is pumped to tank 3. When the water level in tank 3 exceeds the height of the PVC pipe, water will flow into tank 2. Because of siphoning, it will continue to flow until tank 2 fills. (You might need a float valve on the PVC in tank 2) As you use water from tank 2, water will flow from tank 3 into tank 3.

I didn't read this before I posted. Sorry. This is very similar to what Posted above. To keep from having to prime the U-tube, don't come out the top, come out the side near the top. When the water gets higher than the U-tube, water will flow and siphoning will keep it flowing.

Thank you everyone -
Yes, I know that if I have to dig for the new tank, then I could drill a hole in the bottom of each tank and then connect them at the bottom. My worry is that something will happen to those connections - way down at the bottom - it would mean digging about 5 feet down. If I had the connections at the top, and something went wrong, then I could reach it easier.

agmantoo: Does your last reply mean that you also think I should connect the tanks at the bottom? You have given me good suggestions in the past and so just tell me which way you think would work better long term. Keep in mind, please, that I do not have "help" for the most part and it would be just me and a 12 year old doing the digging!

I am trying to plan ahead for "what if" and the main "what if" would be if a pipe is leaking and how would I reach the pipe. But - I also don't want a troublesome "U" connection either.

Sounds like some think the bottom connection is best and it is not likely to fail. Whereas the "U" idea might give me trouble.

Maybe I can dig the hole, set the new tank........rig up the "U" connections and see if it works. We won't have hard freeze here for a while and I can just leave the tanks uncovered (no dirt back fill) until I see if this will work. Then, if it is a pain, then I can drill holes in the bottom.

Thank you everyone - good points.

If it were me I would locate the tanks side by side and a few feet apart and on the same level. I would come up a few inches from the bottom and cut a hole in each tank using a large masonry drill and I would get a short length of heavy wall pipe ( I would try to find a piece of Stainless Steel) and insert into the holes and then I would concrete the pipe in place. It is absolutely necessary that the new tank not have the soil below it disturbed so that the tank remains where you place it. The pipe joining the two tanks does not need to be over 1 inch in diameter. If there ever was a need to access the pipe the distance between the two tanks should let you access the pipe. I doubt that in the lifetime of the boy that it will have to be repaired. Done this manner there is no need to do anything to the existing plumbing.

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Agmantoo
If they can do it,
you know you can!

The Coyote just woke up everyone, a neighbor is out shooting at them and the dogs cannot stop barking......

agmantoo - Thank you. I cannot put the tanks side by side since it is on a steep hillside. I can set them end to end ....but that should be OK too? The water can come into the first tank, and the pipe at the bottom would keep the water level the same in each tank.

Can the Float switch stay in the place it is now....that would be the 2nd tank. The water would go in the first tank........then over to the 2nd one and the Float Switch and pump stays where they are in the 2nd tank?

If the pipe connecting the tanks is way down......it would be almost 5 feet down.....and If I place the tanks as close together as possible........which would probably be 4 to 5 feet apart.....would I just leave the dirt off and there would just be a gap in between them? And I could cover that up with a wood insulated top? Or would it freeze?

Or do things like this just not break? Maybe I am worried about it and I don't really need to worry about it? I just don't want to have to dig it back up!

Thank you. Now, I will try and get everyone back to sleep.......

(Hummm, not sure I remember rewading what kind (material made of) tanks these are? Concrete, steel, plastic? That could change my answer on the type of piping some....)

Me, I would use a flexable connection, poly water pipe or the like, as the new tank will settle a bit. Here in MN we deal with frost 4 plus feet down, so we need to be a bit more robust....

Otherwise agree with him.

You are way over thinking this. Put the pipe down there, make sure the connections are done right with pipe tape and all, or stainless hose clamps, and get it burried.

All the siphon hose or leave open & insulate a little or the like will invite failures, or rodents, or problems.

Make good connections, and get it buried, and be done with it.

With one pipe connecting near the bottom of the tanks, and the tanks not totally air tight on top, the water will rise & fall in both of them at the same time throyugh that bottom pipe. there would be no reason to change anything with your current water supply float or the way you draw water out of the tank. The 2 would act as one with the bottom pipe.

Unless these are very tight air-tight tanks....

--->Paul

Good morning -

rambler: Over-thinking?? Yes, I am accused of that many times! Good point. The Tanks are cement. New cement septic tanks. They are said to hold 1200 gallons but since we cannot fill them all the way to the top, then I think we are holding about 1000 gallons in each tank.

Since the coyote work me up, then I was up and really......really.....really......Over-Thinking this Project and came up with this:

-My lower tank, which is near the spring head, holds only 1000 gallons of water.
-We have an OverFlow spout on the lower tank and until about 4 weeks ago, we always had over flow. In fact, we never could reduce the water level in this tank since we had more coming in than what we could pump out.
-About 4 weeks ago, due to lack of rain, we no longer have over Flow when we are pumping water from the upper tank. The Float switch calls for water up the hill, which takes water out of the lower tank, and the water IN cannot replace the water OUT fast enough.
-My upper tank, near the house, holds only 1000 gallons of water. It has the Float Switch to call for water from the Lower Tank.
-Since we already know that we should not ever use up more than about 800 gallons of water at a time, or the submersed pump would be below water level and we would burn up the pump.....that means the lower tank would be low too and we cannot burn up the pumps.......then......
-Bottom Line: I need a new tank at the BOTTOM of the hill and not up here near the house? I need the greater mass of water down the hill so it can hold it and send it up the hill as needed even when it is dry times and I don't have enough water going in???

I should set the cement tank DOWN the hill, next to the lower tank. level with it, pipe it in the BOTTOM.......like everyone is suggesting........I could set the new tank down in the ground, divert my gravity flow water to it, let that weight of the water settle the new tank, THEN drill the hole.....yes I would pump the water out first (!!! - you guys have taught me a few things!)......I have a gas portable pump I could pump the water back out.......then drill the hole to connect the two tanks.......

Then I can stop Over-Thinking this project and move on to another one!!

How does that sound? Am I correct that I need the water mass down the hill more than I need it up near the house???

And what type pipe to use since it is a cement septic tank? Regular PVC??

Thanks!