Water Level Monitoring and Management

[Catfishnut]

The drip and drain operation is a very good idea, I will have to incorporate something similar for my system.

Since my system will be at my cabin it will be supplied with well water and rainwater. Currently I have two shallow wells (sandpoints) with an above ground pump. Because they are not indoors where it is heated, I have always been shutting them down during winter so they don't freeze and break. I actually do this between October 15 and April 15.

I do not to worry about chlorine or such additives, but the water is very hard and contains a lot of iron. I am therefore going to construct a DIY iron filter using BIRM media. I am also going to install a submersible pump so that I can run it all year. That will also help to regulate the pond temperature since the ground water temp remains a constant 54-56 degrees.
With sufficient water exchange rates, it would keep it cool in summer and warm in winter. I may add some sort of heat exchanger for winter, but that is another discussion.

The drip and drain idea will work very nicely to keep the water level in the total system from getting too low when I am not there. I am right on the river so any overflow can either go right down the ditch into the river or out to my trees and plants to water them. That would put the nitrates to good use. I have planted 20 trees in the past two years and I know that they will appreciate the water!

However, even with all the additional ideas, I still must manage the water level in the last stage of my filter system. If I size the pump appropriately and control it's ON/OFF duration effectively, then the water level should remain consistent. Not too low, not too high and the life of my pump will be extended.

Gordy

 

[Mucky_Waters]

When you gona upload some pictures Gordy?

 

[Catfishnut]

Pix of my system are going to be a while out in the future. I am still at the design table currently. I have several tanks bought and made some prototype pieces, but nothing is assembled yet.

I am currently waiting on a response from a local manufacturer of plastic drums. I wanted another one, 120 gallons, to use for my sediment tank. He hasn't responded yet.

When I do get these filter tanks assembled, I will post some really good photos and I think you will be impressed with the total operation.

Gordy

 

[Catfishnut]

Last night I performed an experiment to verify whether my conduction sensing idea would work to monitor the water level in my filter tank.

I took a plastic spray bottle and drilled two 1/4" holes through opposing sides and inserted a 1/4" stainless steel bolt through each hole. Added some washers and grommets to seal the holes.

I connected the negative lead of a 12 volt power supply to one probe and the positive to the other probe with a 2.2 K ohm resistor in series.

Therefore the circuit is from the power supply to probe #1 - through the water to probe # 2 - through the resistor and back to the power supply. I then connected my digital voltmeter across the resistor to monitor the voltage drop.

When the power supply was turned on and I began filling the plastic bottle with well water, the voltage drop across the sampling resistor indicated roughly 2.3 volts when water first made contact with both probes. As the water level continued to rise, the voltage drop did also until it reached a maximum level of 6.55 volts across the 2.2K Ohm resistor.

Using Ohm's law (Voltage divided by resistance = current or E/R = I) I calculated that the current was roughly 3 milliamperes.
i.e 6.55 / 2200 = 0.002977 Amperes.

This meant that 5.45 volts were dropped across the water itself. Applying Ohms's law once again, (using voltage divided by current = resistance or E / I = R) I calculated that the resistance of this sample of water was nearly equivalent to a 1,830 Ohm (1.8 k Ohm) resistor. 5.45 V / 0.002977 A = 1,830.7 Ohms. This is a perfect resistance value to utilize.

This resistance value will vary with water depth or distance between the probes and with the mineral content and quality of the water, but it is a very good start.

I can now utilize this information to design a pump control circuit based upon the water level in the tank and place the probes at whatever depth I desire to control the pump/s ON/OFF cycle.

What I will do is connect an external 1" PVC tube to the tank (like a sight glass tube) so that the water level in the tube follows the level in the tank, but is not subject to water level fluctuations from the waves created by the aerator. Then I will attach at least four stainless steel probes (bolts) through the PVC tube and connect my cicuitry to the probes.

With some simple transistor logic and minor electronic circuitry/wiring and solid state relays to control the pump motors, I will be able to sense a LOW-LOW-LEVEL point where all pumps should stop pumping out of the tank and a LOW-LEVEL point where pump #2 is not needed to assist pump #1 and should stop pumping. A HIGH-LEVEL point where pump #1 should be running and a HIGH-HIGH-LEVEL point where pump #2 should kick on to assist pump #1.

I will start engineering the monitoring and control circuitry soon!

Dirt cheap, easy to fabricate and install, simple to maintain and almost infallible in operation.

Gordy

 

[Mucky_Waters]

Last night I performed an experiment to verify whether my conduction sensing idea would work to monitor the water level in my filter tank.

I took a plastic spray bottle and drilled two 1/4" holes through opposing sides and inserted a 1/4" stainless steel bolt through each hole. Added some washers and grommets to seal the holes.

I connected the negative lead of a 12 volt power supply to one probe and the positive to the other probe with a 2.2 K ohm resistor in series.

Therefore the circuit is from the power supply to probe #1 - through the water to probe # 2 - through the resistor and back to the power supply. I then connected my digital voltmeter across the resistor to monitor the voltage drop.

When the power supply was turned on and I began filling the plastic bottle with well water, the voltage drop across the sampling resistor indicated roughly 2.3 volts when water first made contact with both probes. As the water level continued to rise, the voltage drop did also until it reached a maximum level of 6.55 volts across the 2.2K Ohm resistor.

Using Ohm's law (Voltage divided by resistance = current or E/R = I) I calculated that the current was roughly 3 milliamperes.
i.e 6.55 / 2200 = 0.002977 Amperes.

This meant that 5.45 volts were dropped across the water itself. Applying Ohms's law once again, (using voltage divided by current = resistance or E / I = R) I calculated that the resistance of this sample of water was nearly equivalent to a 1,830 Ohm (1.8 k Ohm) resistor. 5.45 V / 0.002977 A = 1,830.7 Ohms. This is a perfect resistance value to utilize.

This resistance value will vary with water depth or distance between the probes and with the mineral content and quality of the water, but it is a very good start.

I can now utilize this information to design a pump control circuit based upon the water level in the tank and place the probes at whatever depth I desire to control the pump/s ON/OFF cycle.

What I will do is connect an external 1" PVC tube to the tank (like a sight glass tube) so that the water level in the tube follows the level in the tank, but is not subject to water level fluctuations from the waves created by the aerator. Then I will attach at least four stainless steel probes (bolts) through the PVC tube and connect my cicuitry to the probes.

With some simple transistor logic and minor electronic circuitry/wiring and solid state relays to control the pump motors, I will be able to sense a LOW-LOW-LEVEL point where all pumps should stop pumping out of the tank and a LOW-LEVEL point where pump #2 is not needed to assist pump #1 and should stop pumping. A HIGH-LEVEL point where pump #1 should be running and a HIGH-HIGH-LEVEL point where pump #2 should kick on to assist pump #1.

I will start engineering the monitoring and control circuitry soon!

Dirt cheap, easy to fabricate and install, simple to maintain and almost infallible in operation.

Gordy

Not quite as simple as Dieselflower's system, but it might work.

 

[Catfishnut]

Hee hee!

Yeah, just sitting there in the shade watching the water level rise and fall, [and drinking a cold one], is the most prefered and simplist option. But, I think this might just do the job.
Then again, with this method, I won't have to get out of my chair to turn the pumps on or off. I'll just get up when I need another cold one.

Hmmm, maybe I can devise a circuit to monitor the liquid level in my Anheiser Busch can, trigger a robotic arm to reach into my cooler and retrieve a cold one and also open it for me?????

Gordy

 

[addy1]

The ultimate robotic arm!