The Western Cape region of South Africa is currently experiencing a severe drought, causing
people everywhere to be installing rain water tanks.
Something which is not so easy to determine, is the exact water level of a tank.
Knocking the tank or feeling where it gets colder are not very reliable methods.
This video shows a simple visual system which can be made and installed in about 20 minutes.
The principle utilises a floatation device inside the tank connected to a weight, acting
as an indicator, on the outside.
To prevent the weight from being blow around in the wind, it will have to be stabilised
and guided along an optional scale along its path of travel.
The tank's water level can thus be determined at a glance.
This timelapse shows me busy straightening a desired length of wire, which will become
such a guide.
In this video, two 1000 litre slimline tanks from two different manufacturers are each
fitted with such water level indicator.
Sorry for the sound track, I suffered badly from hay fever at the time.
The plan is to make a level indicator for this tank.
I’m going to use this as a float,
an empty peanut butter bottle,
and a nut on the other side,
connected by fishing line.
So I’m adding a few stones,
trying and get the weight roughly the same.
This should float allright,
but is also heavy enough to be able to pull this up
and down.
The idea is to have this [wire] over here
to prevent it from swinging in the breeze.
The nut will slip over the 6mm wire,
slide up and down and will be pulled up by a string
on the outside. So the first thing is to mark the position
where I want to bend this piece of iron
to stick it to the tank with duct tape.
We need to drill a hole in the overflow.
I am just going to drill a hole with a hand drill
into the bottom of the stopper there.
OK, so we are going to string some fishing line
through the hole to the float on the inside
and the [nut] sliding up and down on the outside.
This tank is empty at the moment, or nearly empty,
which is a good time to start on this system.
Fishing line is nice and smooth
and does not bind easily like a piece of string,
so that is the idea.
I’m going to start at the bottom.
Need about the height of he duct tape to make this mark.
I think we will have to go about the same
for the second mark.
That will be the offset from the tank.
So we have our two marks.
So we go with our first mark.
And we are going to bend it 90 degrees.
Same thing on the second mark.
Now we mark the top height.
About there.
And offset it with the [duct tape] thickness again.
That’s it.
OK, so we make sure that we are
on the same plane when we put this one [bend] in.
OK, so on the one end we will tie on the float
using thin fishing line.
I’m doing my fisherman’s knot here.
Just go over about five times.
Push the end through the back.
And through the loop.
And pull.
Pull it till it’s tight.
And slide it [the knot] forward.
So there’s our float. This will float on the water.
Let’s remove the lid.
And the strainer.
You can see the water level way down there.
So we’re going to drop our float, down there,
into the water,
and push the end through the hole.
We have to tie our bolt.
The bolt can be tied fairly high up
because this tank is not exactly empty.
We will have to experiment here.
I’m going to tie it just here, for the first approximation.
Same thing ... we weave around 5 to 7 times,
put the end through the back,
and pull tight.
Chew off the excess.
I guess that’s about right.
So we will thread this through here
and stick it to the top with a piece of duct tape.
Just clean this up here.
So there’s our offset.
There we go.
This [nut] can now slide up and down.
That’s the theory anyway.
At the bottom, we do the same.
We must just make sure it is absolutely straight
and use a spirit level.
The reason for this piece of metal is to
prevent the weight from swinging in the wind.
Let’s see how it works.
To simulate rain and the water level rising,
you can see the position [level].
As the tank empties,
this will rise again.
I have a second slimline 1000 litre tank.
This one already has water in it and its output [overflow] is in use,
so I will have to drill a hole slightly above it.
Then we have to figure out how to get the [level] indicator to be correct.
I did find a trick on the other side [tank].
Firstly we need to mark again,
so I’ll put it on the ground
and then mark where we’re going to bend it.
One duct tape thickness higher,
another mark – remember not to bend at that mark
– that is just for reference.
So this but will be duct taped to the top.
OK, so I’ll go do the bend.
This is at an angle,
so will have to play a bit to get the angle right.
So, after some fiddling, I have given it the right angle.
So will duct tape it there.
I want to drill the hole somewhere here,
just higher than that [the overflow].
This is just a tiny 2mm hole.
Let’s hope I can pass the string through there!
OK, so we have the string going through a needle
and now it shouldn’t be that difficult.
Ahaa, quite easy ... here we go.
So I have the needle.
To determine how /
where it must be tied, all I do is I just pull on the string
until the bottle is at its highest position,
then I just tie the nut at the lowest position.
As simple as that!
So, just pull it until it stops,
put the nut right at the bottom, and tie!
As simple as that!