Page 1 of 2 12 LastLast
Results 1 to 10 of 14
  1. #1
    Senior Member
    Join Date
    Sep 2003
    Posts
    1,427

    'fuge plumbing question

    I've been adding a 10G 'fuge to my tank and have been using it to learn about plumbing techniques. It's running OK but there are a couple of things which I don't like and think could be made better.

    It's a gravity return fuge (only about 5" higher than the tank). The 10G was drilled for a 3/4" bulkhead on the upper side of one end. I put acyrlic sheets around the bulkhead make a sort of over-flow box. The 10G is fed by a MJ1200. The line to the 'fuge has been drilled with anti-syphon holes. All PVC is 3/4".

    The main problem is the flow through the return PVC. If I run the MJ1200 full-out, I nearly get a flood in the overflow. The flow also 'cycles' with the level of the water going up and down. I have had to put a ball value into the pump to cut down on flow (it needs to be about 50% closed for the level to stay constant).

    I thought that 3/4" PVC should be able to handle 200GPH (estimated flow from the RC calculator). So, I suspect I am either 'messed up' or neglected to do something important.
    Nick

  2. #2
    Senior Member
    Join Date
    Nov 2003
    Posts
    6,316
    You could be getting reduced flow in the output line due to air getting into it. Being that you have an overflow setup in this 10 gallon refuge you will need to address it just as you would an overflow from tank to sump. Dose it make noise that would indicate that air is in the works. You can try up sizing to 1 inch tubing right below the 3/4 in bulkhead so there is NO back pressure in that line as well.
    Rob

  3. #3
    Senior Member
    Join Date
    Sep 2003
    Posts
    1,427
    Let's me make sure I've used the terminology right. I have an acrylic box in the 10G tank with the top level higher than the bulkhead. Water flows over the acrylic. The bulkhead connects directly to 3/4" PVC and gravity-feeds into the 29G tank. There is no u-tube or syphon in the system.

    I can't change the tube size since I have already glued everything.

    There is no gurgling noise but, after my adjustments, the water level only covers 3/4 of the bulhead hole so there must be air in the tubing. Would it help to put a 90 angle connector on the bulkhead pointing down into the water?
    Nick

  4. #4
    Senior Member
    Join Date
    Nov 2003
    Posts
    6,316
    Try slipping a piece of air line down the drain line to help with air movement upward and out. Just feed it into the bulkhead fitting and down the output line until you find the sweet spot when air could be getting monetarily trapped and slowing down water flow. Is your bulkhead fitting 3/4 inside DIA or is the hole for the fitting 3/4 inch? i am asking because you net drain size could be as small as 1/2 inch depending on the setup.
    Rob

  5. #5
    Senior Member
    Join Date
    Sep 2003
    Posts
    1,427
    It's 3/4" inside diameter. Hole is about 1.25-1.5".

    I'll give the air line tube a try. Neat idea.
    Nick

  6. #6
    Senior Member
    Join Date
    Nov 2003
    Posts
    6,316
    once you find that sweet spot try turning up the flow from the power head. you will have to re-find the sweet spot when you do that as it will change with flow rates
    Rob

  7. #7
    Senior Member
    Join Date
    Sep 2003
    Posts
    1,427
    When I put the tube in, the flow improves but there is a lot of air sucked in through the tube with lots of air bubbles in the 29G tank.
    Nick

  8. #8
    Senior Member
    Join Date
    Nov 2003
    Posts
    6,316
    perhaps you are pushing the tube down too far so air is being sucked in instead of exhausted out. If you can not correct it with air line try a tube of bigger DIA so air will not be sucked into the water line. I currently have a 3/4 inch line stuffed into my 1 and 1/2 inch overflow to exhaust air and it is working well. just make sure the top of any tube you put in there is NOT ABOVE THE HIGH WATER LINE of that tank.
    Rob

  9. #9
    Senior Member
    Join Date
    Sep 2003
    Posts
    1,427
    OK, why the CAPS? i'm sure there is some important risk I am missing but my brain has stoped working tonight.

    My testing had the end of the air line above the water line (and it was pushed in a long way (right up to the first 90 corner).
    Nick

  10. #10
    Senior Member
    Join Date
    Nov 2003
    Posts
    6,316
    The caps was to make sure you don't stuff a hose down the overflow and have that hoses top edge above the tanks high water line. If you do you could end up with a flood and that would be a BUMMER. A 3/4 inch overflow should be enough to handle that water supply. how many elbows do you have in the return water hose and are they also 3/4 inch inside DIA?
    Rob

Page 1 of 2 12 LastLast

Similar Threads

  1. Plumbing question.
    By ThisGeekyChick in forum DIY - Do it Yourself
    Replies: 12
    Last Post: 12-01-2008, 03:34 AM
  2. Sump and Fuge Question
    By cdn beaver in forum Lighting, Filtration & Other Equipment
    Replies: 8
    Last Post: 10-12-2005, 03:05 AM
  3. Plumbing question, reducing plumbing for a pump
    By Gools in forum Lighting, Filtration & Other Equipment
    Replies: 2
    Last Post: 06-19-2005, 10:50 PM
  4. overhead fuge question
    By hippo! in forum DIY - Do it Yourself
    Replies: 13
    Last Post: 03-04-2005, 02:26 PM
  5. Fuge Lighting QUestion
    By fishmonger in forum Reef Discussion
    Replies: 1
    Last Post: 08-22-2004, 03:29 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •