Work's fine with SW1 and SW2.
Can LED's be added so that visually I can see that the low or high probes are active?

Try this arrangement.

 

Here is what happens with LED addtion wired up.

Probes out of water. Pump is off, OK. LED2 comes on dimly.
Put lower probe in. Pump does not go on, OK. LED2 goes brighter.
Lower and upper probe in. Pump is on. LED1, 2 & 3 are on. Looks good.
Remove upper probe, lower still in water. LED1, 2 & 3 are all still on.
Both probes out of water, pump stops. LED1 & 3 off, LED2 is still on.

Power cycle.
Probes out of water. Pump is off. LED2 goes on.
Press the momentary switch SW2. Pump goes on. LED1 & 3 go on. When the momentary switch is off LED3 goes dim slowly like the discharge of a cap.

Power cycle.
When I used the trabmitter/receiver/servo, SW1. The same happens as the momentary switch.

 

Add 100K resistors from the base to ground on Q2 and Q3.
Check diode D5.

 

D5 checks out OK. Added those two resistors.
Now....
Apply power. Probes out of water. LED2 comes on. Put lower probe in and out of water, LED2 always on. Checked this multiple times.
Both probes in water. Pump is on. All three LEDS on but LED 1 and 2 are dimmer than usual.
Remove upper probe. Pump stays on, OK. Sometimes LED3 goes off.
Remove lower probe. Pump goes off. LED2 stays on.

Push SW2.
Pump goes on, OK. LED3 goes on and off as SW is pushed. Same applies to transmitter/servo.

 

Something isn't connected correctly is my assessment.
What transistor are you using for Q2 and Q3?
LED3 should not come ON when SW1 or SW2 is pressed because of diode D5.

 

They are both 2N3904's

 

Can you post a photo of the circuit?

 

I'm working on getting it all in Kicad for myself. Give me some time.

It's what you posted in post #101 with the 100k resistors.

 

I'm working on getting it all in Kicad for myself. Give me some time.

It's what you posted in post #101 with the 100k resistors.

No, should look like this:
If LED2 is always ON then R3 must be connected to terminal 1 of the low level electrode. It should be connected to terminal 2.
I need to see a photo of the actual circuit to try and troubleshoot or you can help with a multimeter.

 

That is how I have it wired.

Before adding the LEDs it was wired like you posted in post #84 and that worked fine.

Its a bit of a mess. Not sure what you can see from photos.

 

Not too good with all those wires.
Do you have time right now to troubleshoot using your meter?

 

Yes

Yea the wires got out of hand. Ran out of short wires. I could take it back without the LED's and start over adding them.

 

OK. With both probes out read the voltage on R3 and R5 as shown in the photo below.

 

With probes out of water. 0.56v (LED was off).

Put probe in water went to 4v, then it slowly decreased. And LED was still on.

 

Did it again. LED2 came on immediately. Started out at 2v then slowly decreased.

 

Are you sure the probes are dry when removing from the water?
What are the probes made from?

 

Made from about 20 gauge wire with the ends soldered.

I guess I had the ends to close, first pic. I separated the ends and got consistent results going in and out of the water.

 

Made from about 20 gauge wire with the ends soldered.

I guess I had the ends to close, first pic. I separated the ends and got consistent results going in and out of the water.

What were those consistent voltage readings?

 

When the probe was put in the water, it started at 4.2v. Then it slowly decreased, after about 1 min it was 3.1v and just about stopped decreasing.

 

Is LED2 still coming ON when the probe is out?