existing tank with gha to smaller frag tank

Discussion in 'Beginner Discussions' started by Dean Schreuder, 6 Sep 2016.

  1. Dean Schreuder

    Dean Schreuder

    1 Jan 2012
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    Hi all, need some advise please.
    I have a 2m tank that is overrun by gha, tank was neglected I know it's a big no.
    I plan on starting up my frag tank but how could I do this with using existing rock with corals ?
    I'm sure there would be a cycle that could harm corals... I also was wondering if water from the existing tank would carry the gha over to the frag tank ?
  2. Guest

  3. 2una


    14 Jun 2015
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    1st step i would do is get a Po4 reactor with GFO in it happening & a good PO4 test kit like the Hanna ULR (HI 736).....Get the Po4 low with that & then its probable if the tank has been sitting highish in Po4 that the rocks have sucked it up as well & it takes a long time keeping low levels to get the rocks to stop leaching it.
    Take the rocks over to the frag tank & they still hold PO4 you'll probably see the same issue.
    Po4 down then it can still be stubborn to get rid of but its a starting point.

    With my 600l tank i run 150g of TLF phosban in a TLF 150 reactor with a dialed down small 700L/h el cheapo pump & that lasts just over 1 month before its done.
    That's with no leaching rocks anymore but sorta higher bioload with 25 fish feeding 6 cubes/ frozen/day.
    There's cheaper alternatives to the phosban,i just like it cos it seems to be one that screws with my alkalinity the least.
    Last edited: 6 Sep 2016
  4. RiaanP

    RiaanP Moderator

    11 Aug 2008
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    depends on how much new rock you add. In relation to your current tank. If you got 200kg of live rock in a 500+ system, adding less than 1kg small rock pieces to be used as coral frag plugs. Would not make an impact. Can add them to your sump to start cycling there until the day you need them.

    Alternative is to hold the new uncured rock in a tub for a few weeks, with powerhead providing water movement and a heater. After 3 to 4 weeks you can move it to your sump as well to fully mature. Just just the tub for the worst period, first couple of weeks.

    Yes it will, plus not having vegetarian fish in the frag tank, plus proper lighting to grow corals, would also be a paradise for algae to grow in. Got to get a couple of snails in. Plus if bare bottom, would be easier to clean detritus settlement. Descend water flow would also help against settlement.

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