Odyssea CFS 500 -- massive drop in performance even with new media. Help!

**silentcircuit** · 06-20-2012, 12:19 PM

Okay, I own 2 CFS 500 with the circumference media mod done on both as well as improved hold-down hardware to avoid lid cracking.

A couple months ago one got very noisy and I realized sand had worked its way in to it (I blame the sometimes overactive pleco in the one tank...) and ground down the ceramic shaft the impeller turns on to almost nothing. I replaced the impeller and shaft, and that unit (while still a bit noisy -- I suspect there's not much to be done about this) is working correctly again.

My other unit was not used in a tank with sand and has never had issues. However, recently it started to push far less water than it should, sometimes only a trickle. These pumps are beasts, so something is very wrong here.

My media is almost brand new (it was replaced since this issue started) and the pump itself is not obstructed in any way, nor is the tubing clogged, I've checked it all.

When it gets really bad I'll pull everything apart, clean it (never finding much of anything, honestly -- certainly nothing that would explain this behavior) and sometimes it starts working again for a few days, a week... but never that long. I'll walk by the tank a few days later and notice a film on the surface or almost zero water movement. Sometimes cleaning doesn't work. Sometimes I take it to the bathtub, plug it in to test, and water shoots to the ceiling (as it should) but bring it back to the tank (where the tubing is all fine, not obstructed!) and it refuses to even prime properly.

I don't understand what's going on here -- do I need a new pump? If I do I suspect a new filter is in order, since I don't think you can even get the pumps separate... I am in a very bad place financially right now, so if this thing dies on me there's a good chance I'll have to give up my fish.

**silentcircuit** · 06-20-2012, 4:37 PM

I do have a Laing D5 vario 12v pump I might be able to frankenstein to work somehow, but I'd really rather avoid all that.

No suggestions?

**CWO4GUNNER** · 06-20-2012, 7:11 PM

Last time I changed my 2 CFS500's was OCT 2011. I also use washed silica and construction sand, the little that gets inside the canister is kept out of the pump because as demonstrated in my DIY photo's I completely wrap the outside circumference including bottom and top of both sponge with one single wrap of 1/8" Poly-batten-polishing-blanket. So no sand makes it to the impeller unless you left the bottom of the sponge and around the pump un-wrapped, sand will get in. But im just speculating cause although I could probably ID and solve the problem in 10 minutes if I were there to see what you have (hoses cross, clogged, valve-shut, missing O-rings, pinched or tangled hoses, who knows) I can only guess. Remember your inflow or return hose should be as short, strait and as close to the canister side of the tank as possible, your out flow or pump out hose is the only hose that can be long and angled (no loops) to reach the far side of the tank.

**silentcircuit** · 06-20-2012, 8:23 PM

Same hoses I've been using from the start, and no, I did not wrap the bottom sponge, I'll start that. Sand is not the issue with this unit, no sand is used in this tank. It is not clogged, the valves are fully open, the hoses are not clogged... nothing that should cause this is there. It pumps, but it's at about 1/10th original volume. No missing o-rings and no leaks. Hoses are not crossed, in is connected to in and return to out as always.

**silentcircuit** · 06-21-2012, 11:32 AM

Had it working (sort of) yesterday, woke up to almost zero water movement, opened it up and everything is as it should be (exactly the same as my other, identical unit which is working fine!) and now the **** thing won't even prime. With a bottom motor design. It makes no sense! I tested the pump and it was working properly with everything apart... what is going on here? I really need to take a break from dealing with this thing as it's making me incredibly angry, but I'm afraid for my fish. What the hell is going on?

The pump is strong, if I remove both hoses, put my hand over the output side (proving the top is not backwards and my hoses are on the correct way) it nearly pushes it off if I turn it on for a moment.

I don't understand. This is not a complex system, what am I missing?

**Willard2.0** · 06-21-2012, 12:18 PM

You said the hoses are fine, but everything you have said points to kinked or pinched hoses. It works fine until you attach the hoses. It has plenty of power until you attach the hoses.

Try double checking that the hoses are not kinked around the rim of the tank, or twisted in any way.

Do you have anything that restricts flow on either the intake or output? Too small of a strainer on the intake? A spraybar with not enough holes, or holes that are plugged?

**silentcircuit** · 06-21-2012, 1:06 PM

Update: Well, there seems to be something wrong with the pump after all. I took my working unit, set it in the tub next to the broken one, and switched the cord between them with both full of water to test flow. The broken unit flows 1/10 or less the water of the working one with no tubes or other impedence to flow. It is also much weaker and cannot handle head pressure well. This is /after/ replacing the impeller in the broken unit with a new spare.

What could have caused this? The pump is clean so far as I can tell, nothing is impeding the flow, and it has no moving parts apart from the impeller so if that is working it should work correctly... I still don't understand. I have a new CFS500 on order to replace this one though, as I don't think you can buy new pumps separately. I've looked around a bit without success.

**silentcircuit** · 06-21-2012, 1:44 PM

Final update:

Got it fixed...

Here's what happened if anyone is interested.

There was bypass somehow, and all the crud ended up in the /middle/ of the media, around the interior intake strainer for the pump. The poly batten was pristine around the outside of the sponge surrounding the strainer, but in the middle it was so caked with stuff it was black and a severe impedement for water flow.

Until my moment of desperation I hadn't even looked at the center of the wrap because the outside was so clean. To find it I took all media out of the filter basket and ran the pump alone. Full flow. I then put just the strainer on (thinking it might be clogged at the base or something, though it didn't appear to be). Full flow. I then put the sponge and wrap back on (again not thinking to look in the center). Almost no flow.

Took it off again, the middle was /black/. Pulled the old polybatting off, used just the sponge, full flow. New wrap... full flow.

There was nothing wrong with the pump, the media was just clogging it even though it appeared clean at first glance.

Canceled my Ebay order with topdogsellers, and I'm happy with my CFS500s again.

Moral of the story: Just cause it looks clean doesn't mean it is, and the simplest solution is usually the one that you should be looking for.

Sorry for all the frustration vented here, and thanks to those who tried to help.

**Soulviolence** · 06-21-2012, 2:46 PM

I hope you took Cwo4gunners advice and fully wrapped it this time. I'm guessing that's how the bypass occurred. When I first got mine the intake strainer popped loose somehow and I had poor performance until popping it back on. Glad you got it figured out though.

**CWO4GUNNER** · 06-21-2012, 5:01 PM

When you wrap it this time make sure the bottom of the Poly-blanket is tucked in and sandwiched between the pump housing and inside sponge, like tucking a sheet between the mattress. Also at the top tube cap the other loose end of the Poly-blanket should be gathered and tucked under the strainer cap. All this in my DIY photos. However if you use just one big piece of Poly blanket gathered at just one end like a nap-sack, the only open loose end will be at the bottom and works much better to insure no bypass. Because the circumference cut sponge allows such a huge surface area for the polishing blanket (10 to 1 greater then its stock configuration or the most expensive stacked basket filter), the polishing last for months vice weeks.