External Filters

[tenohfive]

As most of you know, I've been keeping fish for awhile but haven't stretched to an external filter for financial reasons. That changed recently - a forum member approached me looking for a new home for his Rio 180, which came with 2 eheim pro externals and a fluval 4+ which I've lobbed in there for good measure.

I've had a number of drama's since I moved the tank but have finally got around to addressing something which I've been meaning to for some time.

Both filters have a very low output - if it weren't for the fluval 4+ (which in itself is enough to run the tank on) there'd be no surface movement. I'm completely new to externals and only have the vaguest idea of how they work. They were both grinding somewhat, thats something thats come and gone over the last couple of weeks. I opened up one of them the other night briefly, and the top layer (filter wool) wasn't looking overly gunked up. Below that I could see balls of some sort of mechanical filtration (im guessing). I didn't go any lower than that because at the time I had other problems but I've got the time to now.

Someone (waterdrop I think) suggested tilting the filters to a bit less than 45 degrees to clear air bubbles which I'm about to try. Is that likely to increase the output? Or what else should I be considering?

Appreciate anything that'll give me a bit more of an idea of a) how externals work and b) how to deal with the current issues with grinding and low output.

 

[minxfishy]

I dont have eheims so dont know how they work, but have you cleaned out the all the pipe work and impellors? Also are they self priming or do you need to prime them? If you need to prime them have you done it properly? ie made sure they are completely full of water before sealing them up and turning them on?

Tilting them can sometimes release any trapped air, but after a couple of weeks I would have expected this to have gone. The media on the top is usually sponges, second layer is bio balls (mechanical) then either more bio or sponge.

 

[tenohfive]

Tried the tilting method - now one isn't working at all.

I've no idea if they're self priming - I'll try making sure they are full of water.

 

[minxfishy]

Have you looked up the make on google to see if you can find some user instructions?

 

[OldMan47]

If you haven't gone beyond the top layer of filter media, you probably have a big buildup in the bottom of the filter. A typical canister, I don't have Eheims, has a flow path from bottom to top. What that means is the worst of the gunky buildup will be on the bottom of the bottom media. You should take one all the way down and examine each part of the media when you come to it. Chances are you will find a pile in the bottom of the filter case and the bottom filter will be quite dirty. The way to clean almost any canister filter is the same, rinse each element of the filter in old tank water, put that part back in the housing and then do the next part of your media. When everything is back together, put a fresh thin layer of polishing filter on the top of all the media. Clean the impeller and its well thoroughly and put the lid back on. Ensure the filter is primed and plug it in. If there is air trapped in the filter housing it can usually be removed by tilting the filter this way and that to get the bubbles out of the filter.
Depending on how a particular filter is built, the orientation of the filter baskets may or may not matter. In my Rena XP series it doesn't matter because they are symetrical and the inlet flow goes down outside the basket area. In my marineland C-series it does matter because the inlet flow goes through a tube that runs down one corner of all the baskets and the tube at each level must line up with the basket below it and the inlet pipe at the top. In both filters the bottom is the worst place as far as getting a huge build up of mung between cleanings.

 

[tenohfive]

Just taken one down to the bottom...and it doesn't seem that gunked up:

Top basket - filter wool laying on top of balls - gave the wool a few squeezes in old tank water, not too badly gunked up.
Lower basket - carbon filter (probably long dead) with big hula hoops and small hula hoops below it.

The bottom of the canister was just open, a bit of gunk in there which I removed but didn't seem that bad. I didn't try cleaning any of the mechanical filtration and am going out soon, but I'll give that a go tomorrow - but it didn't seem that bad.

There is a central ring that runs down it, I made sure that lined up and the impeller was clear. Put it all back together and the flow was marginally better, but still well below what I'd expect it to be.


I'll google the instruction manual.

 

[tenohfive]

Just had a look at the instructions, no suggestions from there. I think I'll have to take it all apart, bring it upstairs and have a proper look at it at some point.

 

[waterdrop]

Curious, I'm not sure what you've got wrong from your description. You describe the layout of the Pro-style box pretty well.

For comparison purposes in case it helps you, I have probably the smallest Pro box (a model 2222) and my spray bar has 9 holes. When I lower the water level, say 60% like I did yesterday, the output streams have pretty far to fall through air. All 9 of them shoot out about a foot, in other words they arc out and hit the water about 12 inches out when falling about 8 inches through the air, if you follow me. Also, this is just roughly looking at the tank and trying to remember it and give a description, not actually measuring it.

I've never thought about how one goes about doing a flow rate test but I suppose it would involve disconnecting the spray bar and using a fairly large container and timing its fill.. maybe a couple of times to be sure it was consistent I guess.

What model exactly? And perhaps yours are old and there is something that can go wrong with the magnet or shaft or other impeller parts. There are several guys in the hardware section who might be very familiar with this.

Your media sounds different from mine. Mine has "Ehfi Mech" (ceramic rings) filling most of the bottom tray, then a blue coarse sponge made to fit the tray on top of them. The next tray up (I only have two trays) has "Ehfi Substrat" which are ceramic pebbles in most of the tray, then a white pad that sort of a woven fitted pad of polyfloss type material. All of this is straight per manufacturer, as I decided to try their recommendation as a baseline for myself before trying my own changes. Like yours, the empty water space at the bottom has some clumpy mulm when I pour it out during a filter clean, but not really very much as it seems mostly just water. My top pad has not become particularly grungy either.

I'm sure you're making sure the taps are fully opened after you re-clamp the quick release of the hoses, right?

~~waterdrop~~

 

[tenohfive]

Yep, both are as far on as they'll go - turned the output down then up again just to be sure. I don't think they're that old, though I don't know for sure. You've described my filter above perfectly - the carbon filter I described could well be blue - the lighting downstairs is fairly dull.

To give you an idea of flow I can safely say its putting out less than a litre a minute, and the other one about half that. Thats being optimistic as well.

When I have a look tomorrow I might try taking the top assembly off and plugging it in the check the impellers running as fast as it should be. I'll pop a post in the hardware section as well, hopefully someone will be able to point me in the right direction. I'll have a look at the second filter as well - the guy I bought the setup from mentioned that one of the filters wasn't running 100% but thought it was just too much filter wool. Having seen them running in his tank I'm more inclined to think its something I've done in the setup process rather than wear and tear, but I could well be wrong.

Apologies about this, as this is my first external filter I'm not really sure of the obvious things to be checking.

 

[vinylman]

I know this probably sounds like a stupid question but.......you say you've cleaned the impellor, but have you cleaned the slot out where it goes?. A cotton bud or narrow cheap toothbrush is perfect for the job. You'd be surprised how much cack finds its way in there.