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Oase - Not focused on Turnover - Why?!

That's the one @Aqua sobriquet ! Now, that shows (in that particular experiment) that:
  1. At its max turnover, it only reaches 55% of the manufacturer's rating - even with no media.
  2. Only a 3% improvement was seen when all media was removed.
  3. There was only a tiny difference between using 60PPI pre-filter foam and 30PPI pre-filter foam.
That feels pretty low to me, but it is in the ballpark of what I see with my Oase 250.

Now, the interesting thing is that Oase have released a new pre-filter pipe with many more holes, and each hole is larger. Since there is only marginal differences between the media experiments, I can only surmise that the pump is really not that powerful, or parts of the unit design (i.e. the pre-filter) is inhibiting output.

I am waiting for suppliers to get these in and will test if this latest pre-filter design creates less resistance and, therefore, increases the turnover. Oase has said that the new pre-filter is available now, but it will only be available when the retailers order new stock from now. I have asked two of UKAPS sponsors to advise me when the new style design has come in and have committed to ordering a few of them.
 
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Here, on UKAPS, opinion prevails that flow is the king etc. I too share this opinion, with some reservations. But I'm not sure whether this is the demand prevailing among Oase customers. I think they, like any manufacturer, observe customers' preferences diligently. Perhaps they know that customers are focused more on the canister volume and filtration media.
 
_Maq_ said:
Here, on UKAPS, opinion prevails that flow is the king etc. I too share this opinion, with some reservations. But I'm not sure whether this is the demand prevailing among Oase customers. I think they, like any manufacturer, observe customers' preferences diligently. Perhaps they know that customers are focused more on the canister volume and filtration media.
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Indeed, since my joining only 2 months ago it does seem like flow is presented as very important for planted aquariums. In a fish only aquarium (or fish with a few plants) I believe that lots of bio-filtration is the right focus - and flow is a lot less important. I would say 3-4 times turnover is the maximum you would need - providing you have great filtration and plenty of media surface area.

For my little experiment, I am more trying to understand such a reduction in performance from the Oase Biomaster. Something to scratch my technical inch rather than to get the unit to output 900L/ph! The old-style pre-filter pipe does look like a potential bottleneck and would love to test the new one!
 
In thee interim, Oase has responded and provided an update on the new pre-filter pipe design.
  • The new pre-filter pipe is not directly expected to improve throughput. This is because all other pipework, inlet and outlet fittings remain the same.
  • The new pre-filter pipe has been reworked to address the below:
    • reduce premature blocking of pre-filter sponges by having more holes, each with a wider diameter.
    • reduce vacuums and air being drawn into the unit.
    • in turn, reduce decreases in throughput rate as the pre-filter gets blocked with waste.
Overall, the design will address some good issues with the Oase Biomaster that users have been experiencing - so still quite a good step forward. But its not going to increase the overall throughput.
 
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Noise factor may pay a part too, small impellers require high revs and larger ones require more power, I would guess manufacturers take a lot of things into consideration when marketing their products.
Most pumps that produce a high head of water like swimming pool pumps or central heating pumps, have a different shape and design impeller like little buckets that catch a quantity of water and send it on its way rather than a blade that tries to push the water but, can easily slip and cavitate.
The problem with high head pumps is power consumption.
I was a huge fan of using converted central heating pumps, they can run for 20 years or more, are cheap to buy, very well made and virtually silent in operation but burn 40-90 watts an hour.
 
I'm running an Oase 850 on a 90/40/40cm tank, 145L and it seems adequate, wouldn't fancy it's chances much on a 850l tank though. In hindsight , I would have probably just been better buying a smaller filter and a AI Nero 3 for better all around circulation (I am considering a Nero 3 anyway though...).
 
I have an Oase filter. From my koi pond days, if I recall correctly, pump manufacturers use figures based on ‘no load’ scenarios. And head height is the point at which the pump fails to produce any flow. My 350 claims a head height of 1.4m, maximum flow of 1,100 litres per hour and uses a measly 18 watts. Now if I got anywhere near half that flow I would be delighted so on my 60 litre tank it’s not too bad in terms of flow rate. Then you have to factor in pipe friction, valve restriction, inline CO2 diffuser, etc. And the whole Pandoras Box of opinion on dwell/contact time to maximise biological processes. My personal view on this is that Oase aren’t daft and they have made very decent filters that meet the needs of those processes. The purpose of a filter is to filter, and mine does that exceptionally well with the added benefits that it heats the water discretely and has cleanable prefilters that mean I don’t have to dismantle the whole thing. The supplied combination of foams and media, the volume of those, and the flow of the head unit have been carefully balanced to ensure effective filtration. Water movement within the tank is a whole separate issue that needs extra kit whether by running power heads, skimmers with their own flow output, or extra filters that are really there to move more water.
 
BRJP1 said:
In thee interim, Oase has responded and provided an update on the new pre-filter pipe design.
  • The new pre-filter pipe is not directly expected to improve throughput. This is because all other pipework, inlet and outlet fittings remain the same.
  • The new pre-filter pipe has been reworked to address the below:
    • reduce premature blocking of pre-filter sponges by having more holes, each with a wider diameter.
    • reduce vacuums and air being drawn into the unit.
    • in turn, reduce decreases in throughput rate as the pre-filter gets blocked with waste.
Overall, the design will address some good issues with the Oase Biomaster that users have been experiencing - so still quite a good step forward. But its not going to increase the overall throughput.
Click to expand...
The guy in the video I linked did another one in which he drilled extra holes (or made them larger) and it made no difference. It’s good to see Oase say not to expect an increase in flow because others have said it must.
I can see it might alleviate the problem I’m having with my pre filter sponges though so I’ll get the new pipe when it’s available.
 
Aqua sobriquet said:
The guy in the video I linked did another one in which he drilled extra holes (or made them larger) and it made no difference. It’s good to see Oase say not to expect an increase in flow because others have said it must.
I can see it might alleviate the problem I’m having with my pre filter sponges though so I’ll get the new pipe when it’s available.
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Agreed. At least it will be better for air-related issues and (hopefully) extend the cleaning.

I have gone back to Oase and asked about the turnover reduction - including the fact that there is not much difference when the media is taken out! Strangely, there has not been a response to that one just yet .....
 
I’m guessing the flow figures quoted are theoretical? Back when early canister filters had a separate pump fitted on top of the canister I expect would have been easy to hook it up to a couple of hoses and check the output. I’m not sure though how they can do that now though as the pump is built into the head. Running the filter bear bones without media and trays would be seem reasonable but the guy in the video already tried that.
 
The latest update from Oase (who have been great at responding to my queries, not just on this question but for the last 7 months) is below:
OASE: When they measure the flow to produce the flow curve, the max flow is produced and measure direct from the filter as essentially this will be the flow at 0cm, if you are getting roughly 450-550l/hr this would suggest you have the equivalent flow loss of the filter pumping 0.8m to 1.0m up. So with your filter being about ~70cm below the tank, you then have to consider the length of pipework and restriction through the filter. Changing to a coarse foam will help reduce the restriction through the filter, but with your install the flow you are getting seems about normal.
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The interesting part of this is that Oase measure the flow at the filter exit point, and not with any further resistance created by the pipework from the filter exit point to the outflow within the aquarium.
 
BRJP1 said:
The interesting part of this is that Oase measure the flow at the filter exit point, and not with any further resistance created by the pipework from the filter exit point to the outflow within the aquarium.
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That's a variable they can't account for as it changes depending on the length of hose and the number bends etc.
 
hypnogogia said:
That's a variable they can't account for as it changes depending on the length of hose and the number bends etc.
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Yep, it does make sense.

When you also look at the Oase outflow and inflow equipment, it does have a nasty double bend in it. (see below example). I wonder whether this contributes to some form of flow resistance?

FiltoSmart 100 Outlet/Spraybar Set - 45351

The Oase FiltoSmart 100 Outlet/Spraybar Set is a genuine replacement part for the Oase range of External Aquarium Filters. The FiltoSmart 100 Outlet/Spraybar Set is suitable for the following Oase models: Oase FiltoSmart 100 Oase FiltoSmart Thermo 100
www.pond-planet.co.uk www.pond-planet.co.uk
 
I can’t say the actual flow rate from a given filter has ever bothered me. I do understand though why some are disappointed with the performance of their purchase. If I got anywhere near the quoted flow from my Oase 350 on a 60L I’d probably end up with fish soup! 😆 same with the Eheim 350 on my 37L.
 
Aqua sobriquet said:
If I got anywhere near the quoted flow from my Oase 350 on a 60L I’d probably end up with fish soup!
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The correct term is "Fish Breakdancing". 😀
 
Interesting thread. I have a Oase 600 on an Aquael 240 litre aquarium. Nothing else. My feeling is that this creates excellent filtration; the canister itself has a pleasing volume.

Over the last 30 years or so, I kept reef tanks. I was forever adding wavemakers, discarding old ones in favour of newer models, agonising about flow rates, etc. Looking back on it, yes, good flow was important, and I grew enough gorgonians to give them away. However, I think I was also the victim of keeping up with the wavemaker Jones. I suspect that many recommended marine tank turnovers were guesswork.

Thus, I do have some scepticism about increased flow in freshwater planted tanks. Where is this drive coming from? It makes sense in hillstream-biotope aquariums, yes, and I want some flow in my planted tank, but how much flow is enough?

As with a wise comment made earlier in this thread, use your canister for filtration and whatever flow it offers. If you need more, there are some usefully nano water pumps / wavemakers out there. I have the uneasy sense I might end up experimenting with them, but I also have a similarly uneasy feeling that I might be jumping on a bandwagon! [Again!]
 
JohnCooke said:
Thus, I do have some scepticism about increased flow in freshwater planted tanks. Where is this drive coming from? It makes sense in hillstream-biotope aquariums, yes, and I want some flow in my planted tank, but how much flow is enough?
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The higher flow rates that get banded around (x10 etc) are generally for CO2 users, with much lower rates being accepted otherwise. Essentially I guess that as long as your flow is adequate for nutrients to circulate around your tank and for CO2 to be well distributed with minimal dead spots, that is what we should be aiming for. Whether that ends up being under the rough guideline or over will depend on many factors, hardscape positioning, size of tank, efficiency of filter as well as it's hosing route, type of intake/outtake pipes and their position, potential use of wave makers etc. We also need to think of what we're actually keeping in the tanks livestock wise and try our best to ensure their flow requirements are met also, or with area's of a tank with lesser flow for example so they have the option.
 
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