DC8 failed to switch off, could have been real bad
 

I just installed my AC jr and DC8 a few days ago.

I transfered control of my DIY Aqualifter 2-part doser from the digital timer I was using to the AC jr. I programed it to run for 1 minute four times each night. The program allows four 1/4 cup doses of both Calcium and Alkalinity. I tested the setup and made sure that the first dose turned on and off properly and went to bed.

When I woke up I was terrified to find my tank a cloudy mess. The aqualifter pumps were still running and and almost a gallon of both calcium and alkalinity had been dosed into the tank. The pH was 7.5, the over dose had caused a CaCO3 snow and subsiquent drop in pH.

Here's the thing. The AC Jr showed the dosing pumps off even though they were still running. When I went to unplug the dosing pumps from the DC8 just wiggling the cord caused them to turn off.

I haven't yet played around with that particualar outlet again to see if it will repeatedly fail but how common is it for an outlet switch to stick?

BTW, I did about a 50% water change and my water still tested with 500+ ppm of calcium and an alkalinity of 3.5 meq/L. The pH gradually came back up to 7.8 by the end of the day and is now back to normal at 8.0. All in all, I lost a couple of new frags and one fairly established one. It sucks but could have been worse.

Anyone else had this problem?

Yes, the aqualifters use so little power that the soft start on the DC8's keeps them running all the time, you have to put a T on the outlet and plug in a powerhead or lightbulb to turn on with the aqualifter, otherwise it won't shut off. Or get a DC4, they don't have the soft start.

http://www.reefcentral.com/forums/sh...readid=1093095

Cool I just recieved a DC4HD for running my chiller and a few other things but haven't hooked it up yet.

Are there any other common devices that cause this same problem?

Why isn't this mentioned in the DC8 instructions? I think it's a fairly notable issue.

The night light will work for you. I had the same problem, close to cooking a whole system.

Too bad the instructions don't mention it. I would have bought 4s if they had stated the 8s would be a problem to shut down.

What kinds of devices would this be a problem for??

The only devices that have been reported are a rio 50 pump, and the aqualifter.

Curt

It will happen every time with the AquaMedic ReefDoser, AquaMedic SP30000 and the Prominent Alpha 5 metering pump.

5 of the pumps against three DC-8 units and they never worked together. Stopped using the DC-8 for the dosing pumps. I was concerned that the night light would burn out someday and the doser would kill thousands on animals.

I had trouble using a DC8 with my CO2 solenoid. I now use DC4HDs for all critical devices and have had no problems with those.

I just took delivery of two DC8's.... This should be in the literature or at least in the packaged instructions!

Ahh crud, this changes things a little. I planned on two DC8's and I need to controll things like 4 Aqualifters (maybe 5), 2 co2 solenoids (maybe 3), 1 solenoid on the water line, two sets of led moonlights...

Are these going to have issues with the DC8's? I'd planned on getting two of them. Id not care if I could get 2x DC4 for the same as 1 DC8 but its going to put me over budget getting all DC4's...

Just how much load will I have to put on all these low draw devices so the triacs or whatever they are will shut off?

Bump...

Is there any word yet on this issue? I assume its because the load is too small like mentioned earlier?

If so would it be possible to simply parallel a light bulb or something to bring up the current draw? And if so what would be a good minimum total current that needs to be drawn for the DC8's to reliably switch?

Plugging in something along with the aqua lifter is a great way to solve the problem. some say lightbulb, but if the bulb burns out, I think you may be out of luck, so I run mine along with a powerhead, when the aqua lifter is dosing the powerhead turns on near where the kalk is dosed in my sump, it mixes it quickly.

So in solving my problem with the aqua lifter staying on, It also mixes my kalk better. cant loose there.

add minijet 606 to the list of things that don't turn off. I had been planning to use it for fresh water topoff, but found out while testing out the system (still dry) that it won't shut off. Guess I won't be using it for that, lightbulb trick notwithstanding. I'll use a larger powerhead instead.

I had the same problem switching a Tunze nanostream 6025. It never would shut off...at 7W it wasn't pulling enough to turn off the SSR. It must be right on the threshold though, because I moved over one outlet on the DC8 and that outlet WILL switch it every time. I am about to install 2 Nanostream 6045's, they pull 8W, and I hope they switch properly...we'll see.

Hmm, what would provide us with a little extra load that wont possibly burn out like a light bulb... I'll have to think that over... purely resistive load should be best. I could always wire up a big ol resistor but would have to be careful about it getting really hot.

I would think that this soft start stuff would be able to be disabled... are we sure its that thats causing this issue?

By nature...yes.

Well incase anyone wanted to tinker with some electronics... I calculated out quick that to draw an extra 5W of power (at ~120V) works out to be 2880 ohms (P=V^2 / R). I'll have to look around to see if I have a resistor around that size with a high enough wattage rating. And to avoid a single point of failure, like rigging up a lightbulb in parallel with the device, you could parallel two light bulbs (keeping in mind youd then be drawing twice as much of course). Chances are they wont fail at the exact same time and youd probably notice one out before the other goes and could replace before they both go. Just some ideas.

wont shut off DC8 and workhorse t5
 

am in the same boat but, would have thought that my t5 ballast would have no issues shutting off......Fulham workhorse 5 running 2x54 48" actinics. controller shows off except light stays on.....to turn the unit off, I have the unplug it.....makes no sense.

makes no diff what outlet on the DC8 I use.....program works great except as I said, these seems to be power being supplied or something stuck that causes the ballast not to be truly off

not an issue with my other lights (2x icecap 250 MH) i know apples vs oranges. or my 36" T5 ballast on my fuge....not sure that the diff is but thinking of trying to power both t5 ballasts from the same plug of the DC8 see if it is a power issue....very strange.

Ahhh... glad I found this thread. My mini-jet 606 runs my dual reactors (1 carbon, 1 phosban) and it was not turning off even with a manual off. I see now that the dC8 is using the 'soft start' current to keep it going.... phoey! My stand is packed already with fuge light/fans/skimmer so there is no room for another bulb.
I guess I should order a DC4...

Kingfisher - I have no issues using my Icecap 430 ballast on the DC8. It pushes two 48" 54watt T5s.

My Aquamedic SP3000 works on a timer with my ACjr and the DC8.

Geez, the longer this thread goes the more things pop up that seem to have issues. Did they do any real testing on these DC8's? I am really needing a controller here soon, I should have my two new tanks functioning in a few weeks. But this has really got me worried and I may have to spend my $ on another system. I really hat paying more for the smaller DC4's... I see a lot of people mention the DC4HD is the HD the only one not effected or can I get regular DC4's?

Is there any Neptune reps still watching this thread? Is there any plan on a fix in the near future?

The dc4 and dc4hd both do not have the soft start feature.

There are thousands of DC8s in the field, there are few compatibility issues with them. Currently there are several work arounds available for those with a very small pump that has an issue:

- Plug an additional load (small light bulb/wall wart transformer/fan) in parallel with the load.
- Use a socket expansion box to control the device.
- Use a DC4 or DC4HD to control the device.

That said we are constantly improving our products, and always try to minimize compatibility issues.

Curt

Curt,

Other than the intial issues I had with the overdose I have been completely satisfied with my AC Jr, DC8, and DC4HD. However, I don't understand why Neptune having full knowledge of issue doesn't make note of it in the DC8 product description or instructions. There a great deal of low draw items used in this hobby and many of them particuarly dosing pumps can cause a great deal of trouble when they fail to turn off.

I guess all I want to hear is... When will you guys make note of this in your product description and instructions?

Please don't take this as a flame, its not meant to be one in any way

Thanks