RE: Wet-dry standpipe size

>From: Wilson <jwilson at mnw_net>
>By using a center breather pipe, you can regulate the "cone"
>the water forms as it goes down the pipe. By ensuring that the
>water flows smoothly, the noise goes away. The trick is in 
>controlling the waters flow. 

Wow, that's a good idea.  I think I may try that on one of my standpipes to
hopefully reduce the amount of air that winds up going down the J-tube and
fouling one of the siphons on my half-filled 55g.

For my installation, I'd need  to do it a little different because I don't use
a prefilter.  (This would also tend to keep snails from going down.)

               |  |
               |  |
            |  |  |  |
            |  |  |  |
            |  |  |  |
           ~~~~~~~~~~~~ Cut line to save space.
            |  |  |  |
            |     |  |
            |  |     |
            |     |  |
            |  |     |
            |  |  |  |
            |        |
            |        |

Perforating the bottom of the tube would allow bubbles pulled down to escape
into the tube prior to getting sucked down the siphon (hopefully).  

With this particular setup, I'm using 1/2" tubing for the standpipe, and the
standpipe only goes halfway up the tank.  My problem is that the tank is 22"
tall and I have a loopback siphon that goes over the wall of the tank.  If
medium to large sized air bubbles get pulled down the standpipe, the vacuum in
the higher-than-normal siphon can expand those bubbles enough to cause the
siphon to fail.  By way of a faulty design layout, my CO2 injection dumps quite
a bit of bubbles right next to the surface skimmer.  When I refresh a CO2
bottle, I tend to get far more siphon failures than when the bottle is on its
down-side.  (I have a second, substrate-skimming loopback siphon that hasn't
failed to-date, and can take over the load as the water level rises above the
top of the surface-skimming siphon).

I think I'm going to try this with maybe some 1/4" i.d. tubing and see how it

David W. Webb
Enterprise Computing Provisioning
Texas Instruments Inc. Dallas, TX USA
(214) 575-3443 (voice)  MSGID:       DAWB
(214) 575-4853 (fax)    Internet:    dwebb at ti_com
(214) 581-2380 (pager)  Text Pager:  pgr at ti_com Subj:PAGE:David Webb