# best external and new forum idea!!



## nilo (20 Jul 2008)

Im thinking of changing my internal fluval filter to an external filter. the problem is there are so many external filters on the market that its really hard to choose, my tank is approx 150 litres and contains rummy nose tetras and a couple of rainbow fish and quite heavily planted.....

Any recommendations. ? maybe it would be cool to set up a "forum poll" section for people to vote on new products, i reckon it would kind of helpfull for people to make better choices.

thoughts?

marc.


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## Garuf (20 Jul 2008)

The basic guide would dictate you want a filter with a turnover of 1500+lph, this should narrow down your search to filters that will turn over something that high, if not 2 lower capacity filters such as 2 tetratec ex1200's would be fine.


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## a1Matt (20 Jul 2008)

I upgraded from a Fluval 4+ which coped OK when my 160litre tank was running 25W, no CO2 and low planting.  As soon as I started packing the plants in the Fluval struggled. 

So I now have a heavily planted tank with 75w of lighting, presurrised CO2 and a tetratec ex1200.  IMO the Tetratec does a great job.


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## nilo (20 Jul 2008)

funny you should say that matt, i was just looking at the Tetratec 1200 and its definately one i like, made my mind up now! thanks guys!

marc.


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## Garuf (20 Jul 2008)

Before committing to buy I think you should look at Zigs thread on the tetratecs, he found performance to be dissapointing, also noted by supercoley. I think it would be worth looking at alternatives and not crossing off the possibility of having 2.


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## a1Matt (20 Jul 2008)

Glad to have helped.  The ex1200 was one of the first filters I considered.... I then spent weeks deliberating.... and ended up getting it anyway. Am still glad I spent the time deciding though... otherwise I would have kept thinking 'what if I got so and so filter instead' 

Whatever filter I looked at there was plenty of issues. Interestingly except for Eheims.  But I had an Eheim Ecco once before and had nothing but trouble with it


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## GreenNeedle (20 Jul 2008)

Although wew are all quite surprised at the actual lph of these filters being around the 50-60% of advertised lph, it seems to be most externals (including Eheims) and not just the Tetratecs.

The 10x lph is supposed to allow for this reduction in flow anyway (as far as I know)

Andy


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## nilo (20 Jul 2008)

confusion is even worse now!! doh!! so if the Eheim externals stick to what it says on the box (as in lph) surely they are the better ones to go with?..???????????????


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## Garuf (20 Jul 2008)

The idea of recommending the 20x flow rate you'll see bounding about is so that the filter is turning out a genuine 10x flow rate. George is using a fluva 405 on a 60x36x30 tank I use a 2224 you'll see the difference in flow rates, my 700lph filter only does 300lph, I imagine that George's 1300lph does somewhere around 800lph, I know which I'd rather have after all the difficulties I've had with co2 distribution and the resulting algae.


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## nilo (20 Jul 2008)

hmmmm. so the key is to almost double your filter size to get the reccomended filter output as most do half what they say, slightly misleading really, thanks for the heads up though!

marc.


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## ceg4048 (20 Jul 2008)

Hi nilo,
           No canister filter delivers it's rated flow. As they are filled with media and placed further below the waterline the work that the pump must do to overcome the friction presented by the media, and to overcome the weight of the water as it's being pushed uphill takes it's toll. SuperColey1 is correct in that the 10x filter rating recommendation takes all this into account. Filter vendors have not rated their filters for our use, just for the general population of fishkeepers so you have to completely ignore the data on the box. You can use one or more filters to cumulatively arrive at the 10X rating. Also you can use powerheads to achieve the total flow in circulation if economics prohibits you from getting the recommended filter size.

Buying a filter is a bit like buying a car. They all get water from point A to point B. Some are quieter, some are larger and some are less expensive to operate. In that regard a poll wouldn't really help because each person has a different idea of what the perfect car or perfect filter should be. Also, unless each person has tried every filter in a given rating there is no way to say one is better than another. Each can only subjectively say whether or not a given filter accomplished it's expected goal.

As long as a particular filter does not have a reputation of being overwhelmingly inferior or unreliable then it's better to simply get a popular brand in one's price range, unless one has a particular fetish for the features of a given brand. Eheims are noted for their quietness and workmanship for example, so many choose these models if quietness tops their priority list. Some have pumping power rated higher on their priority list and some of the Fluval models do better in that category.

Hope this helps clarify.

Cheers,


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## Garuf (20 Jul 2008)

Yeah that's the case really. Filters are tested with no head and no filter seemingly so once you have your filter under your tank and your media within it the performance decreases quiet substantially. 
I don't know if Ceg agrees on this higher flow rate but it's something I would advocate from my own experiences.


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## nilo (20 Jul 2008)

thanks guys, i think i will go for the 1 external. if i get the right size it should do the job. cheers


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## ceg4048 (20 Jul 2008)

Barr came up with the 3X-5X tank volume per hour turnover. So it's all about achieving that value of actual flow. 10X and 20X filter ratings are merely convenient numbers of getting that but I wouldn't unilaterally suggest 20X for larger tanks just from a practicality standpoint. If we give out rules of thumb they ought to be pragmatic rules. 10X gets you where you need to be, because it more or less gets you to the 3X actual volume per hour (if that makes any sense). 20X is better of course but is only practical for smaller tanks.

Cheers,


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## nilo (20 Jul 2008)

totally lost me mate.

I have good plant growth with what im doing now, i reckon a new external could only make things better, thanks for the advice , things are slightly clearer now. i may just go down to my lfs and see what they have/recommend (keeping in mind ur advice about lph etc). 

ta


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## GreenNeedle (21 Jul 2008)

What we are saying is that if your tank was 100litres then you should aim at a filter that says on the box that it's max throughput is 1000litres per hour (10x)

This 1000lph is what the filter is capable of pumping when it is empty and the hoses are non existent.

Then once you allow for the hoses and the filter media plus things like external heaters, UV etc that are inline your throughput will have been reduced to somewhere closer to 500lph (5x)

This throughput will then be better at moving the CO2 and nutrient around the tank.

As a guide a 700lph filter will say on it for aquariums between 150 and 250 litres.  In reality for us planters we would be using this filter for upto 70 litres or a little more with added powerheads.

Andy


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## nilo (21 Jul 2008)

cheers guys,

been a great help

Marc (aka nilo)


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