Something interesting about RKL ...

[Europhyllia]

I was having trouble with my RKL.
What I wanted it to do is start dripping kalkwasser in the early morning as soon as the pH probe detected pH to go below a certain point. And then of course stop dripping when it got back up beyond that number.
What did happen was that the pump really stayed off until the probe detected pH to be below that set point. But then the pump didn't shut off. Twice I woke up to an empty kalk container and pretty high pH (not above the save limit since the biopellets keep my pH down fairly low)

So I contacted DA and got this answer:

What Channel on the PC4 are you using for the dosing pump? The issue you mention sounds like a known issue related to how the pumps interact with our product (and any control system). The issue you experienced with your pumps getting "stuck" is related to the pumps themselves, and is a known compatibility issue pump manufacturers have with all controllers. Though there are many pumps that work, some pumps are built with poor power factor, which often results in the triac in Channels 2 or 3 to become "stuck" on. Certain pump manufacturers have made claims that they have developed new pumps that resolve this issue, though we have yet to see any of these new pumps in action. The easiest solution is to move the pump to Channels 1 or 4, the relay channels, which will definitely turn the pumps on/off.

So I moved the shadowbox light to channel 3 where I had the kalk pump controller and made channel 4 my designated controller output.
Maybe I am the only one not aware of avoiding channels 2&3 for dosing pumps but I figured we have lots of new RKL users and it might be useful info for somebody.

[txg8gxp]

Good info, thanks. I would have ran into this issue myself one of these days.

[ErikH]

Don't you have to set an "off" into the programming as well as an "on" ??

Also, use port 1 and 4 they are for low voltage devices, I had the same problem with my aqualifter on my Aquacontroller. It would drain my top off every night, then the skimmer would overflow

[Europhyllia]

Don't you have to set an "off" into the programming as well as an "on" ??

I have it set as
on when: BELOW (other option would be ABOVE)
set point: 7.8
That's how the RKL gets programmed. There's no on/off. It's on when the pH the probe measures drops below the set point (and should go off when it goes above)
Sounds like an aqualifter thing then if it does the same thing on the Aquacontroller.

[cbianco]

Karin, I have heard of this problem before on another forum (RC?). Apparently once that individual moved the pump to channels 1 or 4, it worked correctly. Has something to do with the relay, whatever that means, lol.

I'm not an engineer so I can't provide any additional details.

Christopher

[aquasport24]

Don't you have to set an "off" into the programming as well as an "on" ??

Also, use port 1 and 4 they are for low voltage devices, I had the same problem with my aqualifter on my Aquacontroller. It would drain my top off every night, then the skimmer would overflow

Had the same problem with my Aqualifter, even after i turned it off. I think it has to do with the height of the pump (causing back siphon).

[Europhyllia]

Nice. It worked perfectly on channel 4. I'm happy now.

[rockmp]

Nice. It worked perfectly on channel 4. I'm happy now.

Karin,

There is a lot of discussions on this topic on the DA support forum. http://www.forum.digitalaquatics.com/viewforum.php?f=16

What I have read about the PC4 is that ports 1 and 4 are relay ports and 2/3 are different ports. Things like dosing pumps should only be ran on 1 and 4 in order for them to turn on/off per your settings. Hope that helps a little.

[Europhyllia]

I just learned another interesting thing about RKs:

I had to sent back a PC4 because it was messing up the controller. They said the symptoms were consistent with water damage but there where no signs of water damage whatsoever and they replaced it under warranty (the thing never got wet or anything. There was no power outage, etc.)

So I asked if I should plug the PC4s into surge protectors. (my husband hates that extension cord thing though) and mentioned that now I have them plugged straight into the GFCI outlets.
They said they do not recommend GFCI outlets for the PC4s since it can cause damage (not sure how -maybe Alton can explain) to the PC4.

So anyway if you have a choice (I don't I converted all outlets and circuits by the aquarium to GFCI - I do have multiple circuits though so if something trips not all of it goes out), don't plug the PC4s into GFCI outlets

[alton]

They said they do not recommend GFCI outlets for the PC4s since it can cause damage (not sure how -maybe Alton can explain) to the PC4.

I can not believe they recommend not using GFCI's, with that statement here is a scenero for everyone. Someone follows there advice and then gets electrocuted(dead) because of a faulty piece of equipment. The persons family then follows up with the letter or email that DA recommended not to use GFCI's and sues DA. If I am sitting on that jury, it would be pretty easy win for the family.

One other piece of advice before I go away, so many times I see aquarist have there controllers mounted in there cabinets above there sumps and skimmers. My question is "would you store your laptop computer in your aquarium stand every night?"