# Follow up: Dupla CO2 reactor S

```> Date: Thu, 12 Apr 2001 09:44:21 -0500
> From: cameron <ccase22 at mail_com>
> Subject: RE: Installation of Dupla CO2 reactor S
>
> I'm not quite sure I understand what you've exactly said (as 12/16 mm to
> me means VERY tiny tubes), but I think I get the basics.  Four tubes,
> right?  One of size X from tank to filter, one of size X from filter to
> adaptor, one of size <X to reactor, one of same size <x from reactor to
> adptor, and one of size X from adaptor back to tank?  If the return is
> very slow, I would say it is because you reduced the passage the water
> flows through, then raised it again.  That smaller tube into the reactor
> is smaller, so the water probably comes out it with more pressure, but
> it gets to the tank in a bigger tube so that takes some of the
> "speed" of the return.  Does that make sense? If you had the water going
> all the way through it would be normal speed.  If you decreased the
> diameter of the tubes it would come out faster.  If you increased the
> diameter of the tubes it would come out slower.  I am thinking that if
> you decrease, then increase, it would also come out slower.  I for one
> would not get a bigger filter, as you are putting more pressure on the
> pump already (by stepping down the return size).
>
> Anyone may certainly feel free to correct any missunderstanding or
> ordinary ignorance from me :)
>
> Cameron

Yes, there are 4 tubes, one pair with diameter 9/12 mm and one pair with
diameter 12/16 mm... The diagram is as follows: 12/16 --> filter -->
12/16 --> reducer --> 9/12 --> reactor --> 9/12 --> reducer --> 12/16

So if I am right,  you are saying that there should be stronger flow if the
water that leaves the reactor goes back to the tank through tubes with
diameter 9/12 instead of 12/16? You mentioned the pressure on the pump. How
can I know if that's not the problem. Maybe there's already too much
pressure on the pump (now that you mention it, the pump is rather noisy
while normally most eheim pumps are very quiet...).

What do you think?

Davy

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