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.