Advice Required

Douglas Mason

22 Jul 2019

I'll be setting up my 200l tank in a couple of months, tank purchased but due to a leak at home I've had to put the tank build on hold whilst I get new flooring in an decorate.

In the meantime I'm buying all the necessary equipment. I've purchased a doser for EI Dosing and I was initially going to use LCO2 but I've now decided to buy a CO2 regulator kit from CO2art or similar company.

I'm not sure if I should get the in-line diffuser or an in-tank diffuser.

I'm undecided on my filter but I need one where I can clean the pre-filter easily. So I have the following in mind:-

Oase Biomaster Thermo 600
Aquael Ultramax 2000
Fluval G6

My concern with the Oase Biomaster is the flow rate. If I put an in-line filter after this filter then I'll reduce the flow futher however I like the in built heater.

With the Aauael Ultramax 2000 there is more flow but I'd have to put an in-line heater on it such as the Hydor as I don't really want a heater in the tank, this will reduce the flow and if I then add the inline diffuser the flow rate will drop further.

The Fluval G6 is similar to the Oase, in has a 1000 lph filter flow rate and if I add the inline heater and diffuser then this will drop further.

Can I ask what other people with more experience than me would do.

I've thought about running a second filter for heater and inline diffuser or just put the diffuser in the tank.



New Member
26 Aug 2019
London UK
Have you found out any information about this? I have exactly the same problem with my new 200L tank and I don’t want to pick a bad filter and also not sure about the best co2 diffusion for this sized tank


19 Feb 2018
So I'm no expert but I too am in the process of setting up a 200 - 250l tank

After some debating and consideration I've gone with 2 x biomaster thermo 350l instead. My thought process being (i) redundancy - if I have a filter problem or heater problem the other should cover until I resolve it, (ii) I wasn't completely convinced that the 300w heater alone would be up to the job of heating my tank in the colder winter months as mine will be in a room which isn't particularly warm (don't be confused by the advised litreage/capacity of the 600 thermo vs what the heater can actually do (see link below and table within), (iii) that gets me round the flow rate issue and (iv) I've heard of some issues re the 600l version which doesn't seem to be the same for the 250 or 350l versions

I did consider 2 x thermo 250's but when slightly bigger just in case, though together I think they would have done it

Hope I can post a link like this??!!

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