Koralia going backwards?

[fishfrau]

Has this happened to anyone else? I have a 120G tank with 2 Koralia 2s (possibly 3s - not postive). When I got home from work today, I saw a 3" tang stuck in the front of one of them. When I touched it with a net, the pump sucked the fish it right in. It was then I realized that both of my circulating pumps were going backwards - sucking in the wide open center of the front and blowing out the sides. I've pulled them both out, and unfortunately, a second fish had found it's way inside the other one. They were both very dirty, and both had small snails inside them. I would think the poor maintenance would make them stop, not turn the wrong way. Does anyone have any ideas as to what caused this? I'm going to test them in the sink when I finish cleaning them, but I'm afraid to put them back into the tank if they do run right when I test them because it could happen again. Thoughts anyone?

[amnestia]

Never heard of that, sometimes mine would "go back and forth" and just kind of push water everywhere but not that well. Just keep them clean and you should be good.

[StevieT]

I would ask hydor about that. They are driven by magnetic and really can only spin one way, have you ever dissembled them? Do you have them on a controller?

[Hans Dorn]

They can actually spin up both ways.

 

When the pump starts backwards, the propeller is moving out, and is supposed to hit a mechanical stop making it start up in the right direction.

 

Maybe the stop wore off or the propeller can't move freely anymore.

 

So go and clean them already

Edited November 4, 2010 by Hans Dorn

[imsobored152]

mine do that every so often, I just flip the power off and on till its going the right direction

 

Its both the old gen and the new evos

 

And put the fish guards they come with on them. Save the fish

Edited November 4, 2010 by imsobored152

[StevieT]

 

Woah

[ry05coupe]

I just push the propeller back in with my finger. Reverse flow usually comes from the prop being loose. Works every time

[fishfrau]

Wow. Thank you all. I'm glad to hear I'm not crazy. I'm not sure if I want to put something that could change directions by flipping power on and off when I have some of my favorite creatures in the tank. I'm taking those pumps to my lfs tomorrow to get their take on this. I'll update you all. I wouldn't want anyone else to loose two fish in a day to finicky circulation pumps.

[HydorMan]

The Koralia 2 has a robust but simple motor. It is basically just a big roll of copper that electricity passes through, producing a magnetic field that spins the impeller. The reversal can occur because holdhold current is AC (alternating current). This means that the current changed direction back and forth. Depending on when in the AC cycle the unit was turned on, the impeller may spin in reverse. If it starts correctly the impeller is forced down into the motor chamber as it pushes water out the front of the unit. If the electric current is in the wrong direction, then the impeller tries to pull itself out of the motor and up the shaft, sucking water in the process. If the impeller climbs far enough up the shaft, the impeller leaves teh magnetic field, stops spinning and falls back down into the motor chamber.

 

A Koralia 2 could run in reverse if the impeller is impeded and cannot climb the steel shaft to reset itself. I suspect that the snails are primarily to blame for the reversal. They climbed inside the Koralia and caused the impeller to stop. When this happened the impeller resets and starts in reverse. The snails pressence prevented the impeller from reseting itself properly after it was stopped by the snail, resulting in reversal. This is also why that when people modify the Koralia to prevent the noise by stopping the impeller from climbing the shaft, they also see reversal issues.

 

The fact that the unit is really dirty does not help either. The impeller might have been slightly impeded from climbing the shaft by build up on the shaft.

 

A good cleaning and checking to make sure snails are not in the units should eliminate your problem.

[danthenewreefman]

the evo 1400 just ate my tang too!

 

i posted an almost identical question not long ago

 

they're sending me new bushings....kinda still sucks though....

[fishfrau]

When I took my pumps to my lfs, they said that they are really old (I bought my tank etc 2nd hand). They basically told me what Hydor man told me. They have no fish guards, thus snails, fish getting in them. I had no confidence that the same thing might happen again, so I bought two new ones, and increased my circulation at the same time.

[etyrnal]

I've seen this on a SunSun 110 .  I lost ALL of my neon blue rasbora (all nano tank) in about a week.  I was like, this is crazy, i hadn't lost any fish in AGES.  I had my SunSun [these things have AC motors, not DC] plugged into a smart plug that ran the circulation for 15 min at sunrise, noon, and sunset.  One day after feeding the fish i started it manually and noticed food being sucked into the FRONT [normally the output], and being blown out the sides.  I realized what was happening.  The pump would start up randomly in reverse at LEAST 1 in 5 times minimally.  So, i know for a fact that these little AC circulators can start up in reverse.  I've seen it first hand.  I am considering getting DC wave makers now.  But these companies should WARN PEOPLE about this!

I hope i can find truly nano sized wave maker set up.  

These tiny AC pumps will stay running the in correct direction once started up and left running, but it seems that restarts can give you chances of random backwards startups.

 

p.s.  this was a BRAND NEW pump with NO SNAILS, no dirty build up.  An no excuses for the manufacturer.  So if a company tries to suggest it's always the customers fault, tell them to correctly solve the problem and stop gambling with people's creatures.  Or make dc pumps (and add speed controllers while their at it).