Red Dragon 3 Mini Speedy skimmer pump interference with conductivity probe

[pencil3]

It appears that my RD3 Speedy skimmer pump on my double cone skimmer is causing some interference with my conductivity probe in the sump. With the skimmer pump on my conductivity probe reading will jump up by 2-2.5 ppt. In addition to that is seems the readings are not very stable off the probe either, they will dance around a bit. As soon as I turn the skimmer pump off the conductivity probe readings will go back to normal.

I can put a cup in the sump, and then put the probe in the cup. With the skimmer on, as long as the cup is above the water level of the sump, the conductivity will read correctly. As soon as I drop the top of the cup below the water level of the sump the readings of the conductivity probe will jump up. As soon as I bring the top of the cup back up above the water level of the sump the readings on the conductivity probe go back to normal (as the probe is isolated again).

I tried to move the probe around in the sump and it didn't help. The probe wire along with the skimmer pump wire are already as far apart as possible, about 6'. I tested the water with a multimeter, there is no stray voltage. Just for giggles I tried a grounding probe, that did not help either.

I use a Waveline DC 12000 pump for the return, and I do not see any interference between it and the conductivity probe.

Is anyone else experiencing this interference issue?

 

[slief]

No interference with my RD3 and my Apex Condx probe.

 

[Klaus Jansen]

Hi pencil3

it´s possible, if the probeholder is near of the Pump. Why ? The RD3 Pump use a very strong magnets in the Rotor and if he turn in the Stator, he make a magnetic field like as a dynamo. Please put the holder on a anouther place, if it is possible.
Next Point : .. please groundet your tank with a small titanium grounder and the problem is finished. You rconductivity probe working with millivolt and the magnetic field be disturbing the electrode.

Hope it helps...

best regards ... Klaus

 

[slief]

Hi pencil3

it´s possible, if the probeholder is near of the Pump. Why ? The RD3 Pump use a very strong magnets in the Rotor and if he turn in the Stator, he make a magnetic field like as a dynamo. Please put the holder on a anouther place, if it is possible.
Next Point : .. please groundet your tank with a small titanium grounder and the problem is finished. You rconductivity probe working with millivolt and the magnetic field be disturbing the electrode.

Hope it helps...

best regards ... Klaus

Klause,
He said the probe and the pump are 6' (2 meter's) apart and he also said he tried a ground probe which did not help either.

My Conductivity probe is about 2' from my RD3 Speedy pump and I am not having that issue.

Pencil,
When you tested for stray voltage with your multimeter, how did you ground the meter probe? If you grounded to a power outlet, that would only work to test AC voltage and not DC voltage.

 

[Klaus Jansen]

Hi slief...

okay, if the distance is 6 "", has it nothing to do with the pump himself. I heard from a Customer here in Europre, he had the same problem. If he disconect her LED lamp, the problem was fixed. What happend ? The LED Lamp dont have a protective conductor, and the fault current was derived through the protective conductor of the RD3 pump. The grounding plug is prescribed in Europe .Maybe that is indeed connected with it ? Any cheap products in our hobby make fault current and have no protective conductor.

Hope it helps...

best regards .. .Klaus

 

[watsonj]

Bringing this back from the dead, my red dragon 230W and 80W causes havok with conductivity and DO probes I have had to move to another system. when I turn off the pumps everything reads correctly turn them on and they become useless. My tank is fully grounded and has titanium probes

 

[slief]

Bringing this back from the dead, my red dragon 230W and 80W causes havok with conductivity and DO probes I have had to move to another system. when I turn off the pumps everything reads correctly turn them on and they become useless. My tank is fully grounded and has titanium probes

Are the probe lines runnng parallel to the RD3's power cord or the cable between the pump and controller? You don't want those probe cables anywhere near the line between the pump and controller. First thing I would is route the probe wires differently and or move the probes further away from the pump. The motors on the RD3's are not a traditional low voltage DC pump. They are high voltage low current which can interfere with probes if the probe wires are run near the pump cables and or if they are too close to the pump in the sump. That said, I have two RD3 230 on my system and have no issues with the probes but my Controller is on another wall below the tank and the probe wires are also no where near the pump or the pump cables. I have an RD3 80 on another tank and no issues there either but again, the controller and probe lines are on a completely different wall and in another part of that sump.