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  1. #1
    Member LowKey's Avatar
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    Decisionís Decisionís Bulkhead Placement

    Well, I just picked up my 1.5Ē bulkhead for $15.00 from the boys at Marinescape on Carling. So Iím ready to drill the 2.5Ē hole on the back pane of my tank.

    Iíve come up with several ideas. Which one should I go with?


    The two main issues for me are:
    capability
    cosmetics

    Heres a look my plans for both suction and return:


    Im gonna go 3/4" for the return.

  2. #2
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    With a Mag 7, you should probably use 1 1/4" or 1 1/2" return plumbing (even though the connectors are 3/4"). i think this is recommended in their user's guide. BTW, RC's head loss calculator suggests that a Mag 7 with 3/4" plumbing will only flow about 400GPH (this increases to 470 GPH with 1 1/2" plumbing). That seems low for a 90G. Will you be having other flow sources?

    I'm using option #3. Option 2, with two drains, would provide good back-up and additional capacity.
    Nick

  3. #3
    Member LowKey's Avatar
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    Originally posted by nickb
    With a Mag 7, you should probably use 1 1/4" or 1 1/2" return plumbing (even though the connectors are 3/4"). i think this is recommended in their user's guide. BTW, RC's head loss calculator suggests that a Mag 7 with 3/4" plumbing will only flow about 400GPH (this increases to 470 GPH with 1 1/2" plumbing). That seems low for a 90G. Will you be having other flow sources?

    I'm using option #3. Option 2, with two drains, would provide good back-up and additional capacity.
    I dont want too much flow going through my sump. 400 - 450 is about what Im looking for. This will insure effecient filtration time through the sump. I wil be using three power heads to direct flow to specific areas within the tank. All in all were looking at 800gph of flow within the tank.

    Thankyou for the response. I will keep the ratios you brought forward in mind.

  4. #4
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    Sounds like a good plan. I think the issue with the outflow pipe size also concerns power consumption by the pump and stress, not just the flow rate.
    Nick

  5. #5
    Member LowKey's Avatar
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    Originally posted by nickb
    Sounds like a good plan. I think the issue with the outflow pipe size also concerns power consumption by the pump and stress, not just the flow rate.
    Great points!

    Actually the outlet on the Mag 7 is 1/2", and its recommended to double the outlet size when selecting pipe. Therefore, 1" pipe is recommended. So what Iím going to switch the flex hose to 1" but keep the plumbing beyond the "T" fitting at 3/4". This should alleviate unwanted stress on the pump yet stay within 400-450gph of flow through the sump.

    Thanks Nick, exactly the kind of suggestions Im looking for.

  6. #6
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    Yeah, I was thinking of a Mag 9.5 (which is what I am installing). But the doubling in size is still their recommendation.
    Nick

  7. #7
    Moderator cres's Avatar
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    The other thing to keep in mind is that invariably, some buildup will coat the insides of your pipes, impeller, etc. and the flow through your return will diminish, to a point, over time.

    Things liike bubbles and "too much flow" will reduce over the first month or two.

    I would suggest option #3 on the drain. If you ever have to rework your drain, you need only drain the tank to the bottom of the hole. With option #1, that would be significantly more water. I would suggest 2 #3 options before your #2 option (it would mean two holes/bulkheads instead of one).

    I'm a little concerned that you refer to it as the "suction" and return. With your "suction" feeding the skimmer and fuge. This looks to me like a restriction of your drain line. This should always be able to handle the full flow of the drain line.
    Sarchasm: The gulf between the author of sarcastic wit and the person who doesn't get it.

  8. #8
    Member LowKey's Avatar
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    My tank was drilled successfully last night by the boys at "The Glass Shop" on Clyde Ave. It took about 5 minutes of drilling and it was done. I went with a 2.5" hole to fit the 1.5" bulkhead. I'll tell yah, watching your tank being drilled gets the old heart going thatís for sure. All in all it was a smooth process, with tones of water.


    I decided to place the hole in the center of the tank 3" from the water line. Im going to build an overflow instead of using a reducer as a skimmer.

    Thanks for all the advice thus far. Im now going with 1" top to bottom for the return as recommended for the Mag 7. I will ensure my drain line flows freely by using a 1.5" feed line to the "skimmer section" of my sump.

    All my parts are purchased and almost ready to be assembled. I cant wait yet I must remain patient.

    90Gal Tank 35Gal Sump

  9. #9
    Moderator cres's Avatar
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    Yeah, something about glass makes drilling seem like a really bad idea.

    I've seen it done a couple times now and my brain sees that it is possible, but, it still feels wrong.
    Sarchasm: The gulf between the author of sarcastic wit and the person who doesn't get it.

  10. #10
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    Cool

    opttion #3 is best but,, do 2 drains. one on each side.
    always best to double up just incase something gets down that drain or covers a screen etc,, it can happen and almost always will! also, feed you skimmer with a pump not the drain. you need force into the skimmer plus skimmers need to be tweaked.

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