Filter Pump For Juwel Rio 180

Hi All,
Tanks background: Been running my tank for about 6 months now, it was second hand when i got it and has been running for about 7 years all told. Currently semi planted with a piece of bogwood/hidey tube for plecos.
Currently battling high nitrates (previous owners - old tank syndrome?!) but fish are dealing with it, as they have done for years. Just keep persevering with water changes etc - need to get rid of one of my plecos tbh.
(any takers?!)

Anyhoo, onto my reason for posting, noticed a split in the cable housing of my current pump so went to LFS to buy a new pump, got what i though was correct one, looked exactly the same on the box, seemed to indicate it was for my filter, but when i came to putting it in my tank i found it was a 400L/H pump rather than the 600L/H i'd just taken out. 
Will my tank cope with this smaller flow filter pump or do i need to get the larger one, or does anyone have any suggestions for improvements i could make (if im going to change it i might as well make it better if i can)
Thanks in advance
Lindsey

Having a Juwel Rio myself, I know that Juwel seem to think that a slower flow rater is better for a filter as the water hangs around longer in the media which gives the bacteria more chance to get the ammonia and nitrite. But 400 litre/hour is a bit too slow for a 180 litre tank.

I would add two further things as causes for high nitrate - having too many fish and feeding too much.  Uneaten fishfood is broken down to ammonia which is then processed exactly the same way as fish waste, resulting in ammonia being made. And with an overstocked tank you have too many fish all making ammonia which ends up as nitrate.

The usual concensus about Juwel filters, with the correct pump, is that they cope well with a light stocking and non-messy fish. Plecs are messy fish. And you say you have more than one.
Do you know what kind of plecs they are? Some stay small enough for a 180 litre tank, others get way too big. If your plecs are common, sailfin or gibbiceps plecs, you need to rehome all of them.
Could you list all the fish you have in the tank and how much/often you do a water change,  then we can see if the nitrate problem is due to overstocking or insufficient water changes.




And back to your filter pump problem - you could always get another filter! Either a second small internal (though that would clutter your tank with boxes) or an external, and remove the built in Juwel filter. I removed the Juwel filter in my Rio 125 and replaced it with a different make. If you get a second internal, chopping up a bit of Juwel sponge and putting it inside the new one would help grow bacteria in that. With an external, just put all the Juwel media into it and fill the spaces with the media that comes with the external.

Leaving out the plecs and the suckermouth catfish for now the rest of the fish should not be a problem with the built in filter (with the right pump). Using the unreliable 1 inch of fish per gallon, you come out at max stocking, though as most of those fish are not big waste producers you are realistically understocked - without the three fish I named!
The L022 plecs grow to 12 inches/30cm when not stunted (checked on planet catfish) so even one of them will make a serious dent in your stocking level. I wouldn't be surprised if they are what's pushing up your nitrate.
Have you tried aquarist classifieds (google it  )? You might find someone on there who'll take one of them.

As for the suckermouth, look up chinese algae eater, Gyrinocheilus aymonieri. There is a gold version as well as the standard grey one. These are commonly sold as algae eaters and are often labelled as sucking loaches. The problem is they grow to 28cm and as they mature they stop eating alage and develop a taste for the slime coat of other fish. If it does turn out to be one, I would get rid of it asap.


In itself, a nitrate of 60 is not a problem. Nitrate only becomes a problem to the fish in the hundreds (except for a few nitrate sensitive species). But once it passes the tap + 20 level just before a water change, it does indicate something not right in the tank. In your case, I personally think the 'something not right' is the two plecs.
To get rid of seroius amounts of nitrate, the plants need to be jungle-like