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Discussion Starter · #1 ·
Hi everyone i am thinking of buying a Fluval 205 and was wondering if the 205 would be adaquate for my 190litre tank as i do not want to jump to the 305 if i do not have to as money is scarse with christmas and a new baby on the way, I hope someone can point me in the right direction, I am replacing a Juwel filter system witch is a load of crap, my tank is a Juwel Trigon 190litre, Hope someone can help.:help:
 

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I think too small, but maybe ok it you keep your bioload low and aren't too concerned growth or algae issues in some parts of the tank due to poor flow.

I have a 305 on my 46g (175l). I'd say spend the extra $35 on the 305 unless you are getting a screaming deal on the 205 that you can't get on the 305.

BTW, the specs on the 205 say "up 200 Liters (40 U.S. gallons)". Fluval needs to learn some basic math. 40 gallons is about 151 liters. I don't know whether to believe the 200 liters or 40 gallons figure.
 

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Discussion Starter · #3 ·
Thanks cjp999 for the quick reply, The 305 is only £20(£69.95) less than the 405(£89.95) would the 305 definatly do the job or should i pay the extra and get the 405 and have you had any problems with your 305 or should i be looking elsewhere for a filter system, Thanks again Steve
 

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Thanks cjp999 for the quick reply, The 305 is only £20(£69.95) less than the 405(£89.95) would the 305 definatly do the job or should i pay the extra and get the 405 and have you had any problems with your 305 or should i be looking elsewhere for a filter system, Thanks again Steve
I don't have any issues with my Fluval, and I believe it is considered to be a highly rated brand.

Here's what I can find on the 205, 305, and 405 with current sale prices from Big Als:

205

  • $115
  • Rated for up to 40 gallons
  • Flow rate is 100 gph
305

  • $150
  • Rated for up to 70 gallons
  • Flow rate is 185 gph
405

  • $200
  • Rated for up to 100 gallons
  • Flow rate is 225 gph
From what I've read, you want a flow rate of 10x (minimum of 5x) your tank size for optimal distribution of nutrients and CO2, but this does not all need to come from the filter. You can supplement your filter's flow by adding a powerhead.

Filter size is more critical when is comes to biological filtration. You need to make sure you have something big enough for your bioload. This is why I said you can probably get away with with the 205 if you don't have a heavy bioload, but you may have flow issues that affect algae and plant growth. The later you can fix with a powerhead. Excess bioload you can fix with a bigger filter, or by adding a sponge filter (kill two birds with one stone by adding a powerhead with a sponge filter).

A 405 is probably not overkill for your tank, but you probably want to distribute the output over more than one place, either with a spray bar or two or three outlets. It still however falls shorts of optimal flow recommendations, so you may want to add a powerhead. I don't have a powerhead on my 46g with Fluval 305, but I probably should add one. Since I just have med/high light and DIY CO2, my growth is not that great, and I'm guessing having great flow is not as critical as it would be in a high light high CO2 tank.
 

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The 205 is rated for a tank up to 200 litres, so in theory it´s the adequate size, BUT in all honesty going larger will only do best in the long term, if you can find an extra 40 bucks you won´t regret it.

I have a 305 for a 240 litre tank and a FX-5 for the 400 litre and definitely recommend the Fluvals
 

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FYI, here are the Fluval tank size ratings from the manual:

105: 25g or 100l
205: 40g or 200l
305: 70g or 300l
405: 100g or 400l

So clearly something is amiss since the g/l ratio is not always the same. It goes from a low 1/5 to a high of 1/4. It should be 1/3.8. If you believe the gallon rating, the table should read:

105: 25g or 95l
205: 40g or 151l
305: 70g or 265l
405: 100g or 379l

The liter capacity of the 205 is either overstated by about 33% or gallon capacity is understated by 25%. For all models the liter capacity is overstated or the gallon capacity is understated (or maybe a bit of both).
 

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I have a 204 in my 20 gallon (about 80 litres) and had to add a Koralia nano powerhead when the plants filled in. A Rena Filstar XP1 would be more like it in my 20 gallon. If you are going high light and injecting CO2, get a 405. Those ratings are not anywhere close to realistic.
 
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