Substrate frustration

Discussion in 'General Discussions and Advice' started by costa, 30 Sep 2009.

  1. costa

    costa

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    Hi Guys,

    I've had my 250 litre sump tank cycling for 2 weeks now.
    I have about 10kg of live rock as well as a lot of crushed coral.

    My question is this:
    I have done a lot of reading subsequent to the purchase of the crushed coral.
    Quite a few people are against crushed coral because it can lead to a big build -up
    of nitrates.
    They advocate Aragonite or fine sea sand.
    What do I do, because I have spent the money on the crushed coral now & I
    am not sure how I will replace it in the future if I have to??

    Appreciate your advice!
     
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  3. Annoying

    Annoying

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    I'm not certain about what to do with the crushed coral but the cheapest alternative is reggies playsand. Maybe you can "crush" the crushed coral even more untill it's a sand substance...
     
  4. magman

    magman

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    Hi Costa,

    I promise you that you will not regret it. I changed two weeks ago from crushed coral to reggies, I have a six foot tank, 1830x610, and I used 100kgs of reggies. It was R40 for a 20kg bag, I think 60kgs should of been fine. It looks nice and looks much more natural than crushed coral. Check the pics from my post.

    just make sure you keep your rocks under the water when you change, and I would say change as soon as possible.

    I was reluctant, especially in a running tank with livestock, and I wish I had done it sooner.
     
  5. Neil H

    Neil H Moderator MASA Contributor

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  6. RiaanP

    RiaanP Moderator

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    some garden centres that sell compost, sand , topsoil etc, have playsand.

    A lot cheaper that reggies. R40 for a bag I cannot pick up.
    Two workers loaded it into my car boot, and I could not get it out... :)


    But believe me, it is 100% better that crushed coral. I wish the petshops will wake up and stop selling crushed coral bags, but Play Sand instead for those who cannot afford aragonite. But play sand is cheap, and a lot more $$$ can be made from crushed coral.
     
  7. Neil H

    Neil H Moderator MASA Contributor

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    just remember to wash the play sand like 20 times .... literally ....to get rid of all the $^$$^$
     
  8. Sentari

    Sentari

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    I'm sure you guys have seen me ask the same question over and over. Maybe Neil and clarify this for me.

    I have sugar fine crushed coral. What would be the reason for me changing to aragonite or playsand?

    My crushed coral is really fine... i wouldnt see a problem with fine sand... Any views?
     
  9. crispin

    crispin

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    id be intrested to see what sarah feels on the topic of substrates, but do bare in mind that she is in the States and thus probably doesnt have the local application to reggies as we do.

    I would hesitate to crush the coral finer as the pieces tend to be sharp and damaging to things that live in the substrate. thats the life from worms to wrasses and the like that burry themselves. For this reason i would also hesitate about getting anything but play sand (Riaan are you sure that stuff from garden centres is play sand and not a form of river sand?)

    one things for sure, you want a decent substrate or no substrate a long way before having the wrong substrate and crushed coral seems to lead to all sorts of problems.
     
  10. crispin

    crispin

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    shape (as in sharpness) would be my only personal concern. If it was eroded and thus rounded to a degree then i should think its fine. I do agree we worry more about size (sugar fine is great) more than shape though, certainly when looking at the question of detritus trapping at any rate.
     
  11. sihaya

    sihaya

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    crushed coral is fine so long as you have enough other filtration... and so long as you vaccum it when you do your water changes
     
  12. Midasblenny

    Midasblenny

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    I`ve never used anything other than fine crushed coral and kept the depth thin, no worries with it at all.
     
  13. IMarine

    IMarine

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  14. Slummies

    Slummies

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    do you get commision?

    just playing mate, cheers:peroni::thumbup:
     
  15. IMarine

    IMarine

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    hey bra how i wish:thumbup:, between caribsea and seachem i should be a rich man,you see if anybody have not used caribsea or seachem they will not now the benefits,but those who say that silica sand works all the best for them
     
  16. riyadhessa

    riyadhessa

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    Totally agree bra...
     
  17. Neil H

    Neil H Moderator MASA Contributor

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    do you have any data or scientific source other than heresay which supports this silica leaching process ??
     
  18. RiaanP

    RiaanP Moderator

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    If sand leached silica, so would the glass... it is inert.

    Yes Crispin, it is playsand, just ask for the right thing. Apparently WASHED playsand... but you still have to wash it like mad. Same thing as at Reggies, bigger bag, cheaper, and just as dirty.

    My kids Pre-school (not too long ago) had an enormous sand pit. About 40m by 15m.
    They bought play sand by the truckload every year-end to re-fill the sandpits. Because of the sand that ended up in the kids shoes and pockets. Should have seen my car back seat sometimes. Wonder what it would have cost to fill that pit with Reggies sand?
     
  19. Sentari

    Sentari

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    Thats exactly what i thought. I will try find a decent picture to give you an indication of what it looks like. I havent had any problems to far.

    Cool thanks sihaya! :)

    Cool thanks for the input Robin.
     
  20. Nemos Janitor

    Nemos Janitor

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    Crushed coral has a higher density than aragonite and calcium carbonate. It therefore does not bind other carbonates like phosphate etc as easily. OK to use fine CC IMO.
     
  21. Neil H

    Neil H Moderator MASA Contributor

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    completely agree, and agree with Crispin re the shape of the particle


    IMarine, my appologies.

    I have been doing some research into silicates or more importantly what is referred to as soluable silicate. I stand corrected in that there is evidence to show that certain silicates can under certain circumstances become soluable. the article that i am reading at the moment suggests that silicates in the order of 1 to 5 ppm may be disolved out of solution from a silicate based playsand mix although these numbers are not specific to south african silicate sand sources and in addition are related more to the impurities in a silicate sand than the silica itself, indeed no distinction is made between whether the silica in solution relates to the impurities or the silica.

    This particular article argues that there is a case for dosing silicates into a marine system, but that the irratic generation / variability of the soluable silica generated from silica sand is not a sufficient source for the marine creatures requiring soluable silica, and the author advocates additional silica dosing.

    I will endevor to continue researching this phenominon and report back when i have some more information.

    To date i remain unconvinced that silica sand is bad for a marine tank, indeed if one accepts that a certain amount of soluable silica is desirable for organisms (aside from diatoms of course) and that while variable, silica sand does supply this then there is a distinct argument that silica sand is one of the better gravels to use. As an interesting fact, Aragonie also leaches detectable amounts of soluable silica.... but at a much lower concentration than silica sand (about half to be exact) and again as a result of impurities within the aragonite.

    I will also be looking into the rates at which the available soluable silica disolves. it APPEARS from my research that the silicate that can be disolved into water (i.e. the soluable silicate) will do so in a matter of days or weeks at the most, and in addition, organisms in the tank (NOT exclusively diatoms) will use this silicate up in an equally speedy fashion. thus there is an argument that putting silica sand into water and replacing the water once a week for 2 or 3 weeks would see the vast majority of the soluable silica removed from the sand (although this is simply a hypothesis at this stage)

    I have 3 or 4 different articles which i will be reading and re-reading and will make a thread about this when i feel i understand it fully.
     
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