Biomaster Pre Filter

[Aqua sobriquet]

After watching a YouTube where a guy modified his I wasn’t expecting it to work. Curiosity got the better of me though and I had some overflow pipe …

I used the same 5mm diameter holes as the original but increased the number from 16 to 30. As far as I can tell it’s made no difference at all.
If it has improved the flow then it’s certainly by only a tiny amount on my filter. Conclusion - don’t bother. I’ll be putting the old pipe back next time I clean the pre filter. I’ll keep it though in case it works with the larger impeller when I try it again.

 

[Karacticus]

Thanks for the info! Funnily enough, I have recently acquired some overflow pipe to try the same thing on my 850. I was hoping to increase flow and maybe reduce the burping it does every minute or two. I have read this is likely to be because of the filter drawing in air at the seals, so increasing the pre-filter flow and reducing the pressure somewhat might reduce that. I was also going to add some Vaseline to the seals.

I was going to try drilling a lot of holes!

 

[Aqua sobriquet]

If you have the pipe give it a try, maybe it will work for you? As I mentioned in another thread I can’t help thinking Oase optimised the flow for the impeller used.

 

[Karacticus]

I've replaced the pre filter tube today adding about 50 holes, slightly bigger than the previous. Pretty sure it's made a difference. The surface flow spreads out much wider than before. The blue line is roughly where it was before the change and my salvinia was well spread out outside of the blue line. Now it is pinned into the back corner. Should have done a before and after photo, but think it's helped.

Vaseline on the seals hasn't made any noticeable improvement at this stage.

 

[hypnogogia]

As far as I can tell it’s made no difference at all.

I’m pretty confident that the sum total surface area of the holes in the pre filter tube are more than the cross sectional surface area of the 16/22 hose or other ‘piping’ in the filter, so I would think that adding more holes will make a difference.

 

[Wookii]

increased the number from 16 to 30

Why go to all that effort and add so few holes?

You’re aiming to reduce the pressure loss through the tube and the sponge as much as possible. You could easily add another 60 holes to that larger diameter tube.

Edit: Its also worth noting that any gains for increasing pressure loss through the prefilter may also be dependent on how you have the rest of the filter set up. If you have all the trays packed with media, or have some other fine filtering items in there, modding the prefilter might not make much difference as that won’t be the bottleneck.

 

[Aqua sobriquet]

Why go to all that effort and add so few holes?

If virtually doubling the number of holes has made no noticeable difference what makes you think adding any more will?

 

[Wookii]

If virtually doubling the number of holes has made no noticeable difference what makes you think adding any more will?

What makes you think adding more won’t? It’s not necessarily a linear relationship.

If you want to perform the acid test, remove the prefilter sponges and tube completely and see if there is any increase in flow.

If there is, you know there is more scope for increasing flow with further modification to your prefilter, if there isn’t, you know there are bottle necks elsewhere preventing you from seeing any improvements in the prefilter modification.

 

[Aqua sobriquet]

What makes you think adding more won’t?

Because I’ve already added a larger pipe and almost doubled the number of holes already and it’s made no difference.
I should add by the way that drilling a few holes in a pipe doesn’t take as much “effort” as you seem to think. 😉
As this guy found out, he also doubled the amount of holes and it made no difference.



The next time I take the pre filter out I’ll make some more holes in the pipe just to be sure. I’m not holding my breath though that it’ll make any difference.

 

[alnitak]

Hello, I made some holes on the outlet pipe of the filter (the plastic hose between the filter and the lily pipe), and it made a great difference: now the carpet on the ground is completely wet...

Ok, it was a joke... So I doubled the number of holes in the prefilter tube, no change on the flow... The only way for me to moderate the burping was to tilt the filter permanently (lets say 10-15°) with a piece of wood below. There is still some air exhausts from time to time, but it is far less noisy as it was before, and when I tilt the filter, there is no more "3 minutes f..king air purging". Let's admit it is a little improvement

 

[Wookii]

I should add by the way that drilling a few holes in a pipe doesn’t take as much “effort” as you seem to think. 😉

It barely takes any effort at all, and it's only going to have either a zero to positive effect, not a negative one, that's why I can't quite understand why you're making such a huge deal out of it lol

It's literally just a case of - if you want to have a go at it, stick some more holes in the tube - if it helps great, if it doesn't you've lost 5 minutes of your time, so its hardly worth debating.

As this guy found out, he also doubled the amount of holes and it made no difference.

He's doing it on an Oase 350, which is one of the small lower powered models, plus we don't know how he has the media configured. Most people who seem to have seen a positive impact from this mod are doing it on the larger 600 and 850 units. They are the ones I have, and I would expect those with the larger pumps and more media trays to have to push through, to be more likely to see a larger flow difference for any modifications that reduce flow restriction.

Obviously anyone who has constricted flow through the main filter due to using trays filled with Matrix or Eheim coco-balls etc in place of the stock plastic media probably aren't going to see any changes from the pre-filter - as with many things in this hobby there are lots of other variables, and as always YMMV.

 

[alnitak]

Most people who seem to have seen a positive impact from this mod are doing it on the larger 600 and 850 units

Hello, mine is 850, no improvement. filter load = 2 baskets with origin blue sponges, 3 baskets with aqua neo soft media

 

[jsoto2005]

W

Hello, mine is 850, no improvement. filter load = 2 baskets with origin blue sponges, 3 baskets with aqua neo soft media

Well that’s that then. Can’t argue with honest reviews.. well some still might 😹

 

[hypnogogia]

This is really easy to test. seal one end of the pre filter tube with your finger and old the open end under a running tap that’s fully open. Are you able to make the tube overflow or does the water drain out through the holes? In my case I’m unable to Lane the tube overflow, so drilling extra holes would make no difference, and we have high water pressure.

 

[Aqua sobriquet]

It barely takes any effort at all, and it's only going to have either a zero to positive effect, not a negative one, that's why I can't quite understand why you're making such a huge deal out of it lol

I’m not, you’re the one who said, and I quote “Why go to all that effort and add so few holes?”
And as this guy says, changing the media isn’t going to do much. 😉

 

[Aqua sobriquet]

Hello, mine is 850, no improvement. filter load = 2 baskets with origin blue sponges, 3 baskets with aqua neo soft media

Mines a 350. Two trays of sponge, two of fairly open bio media and some carbon in the top tray. I have experimented a little since I’ve had it but I can’t see any difference in flow no matter what’s in the trays.