Alk, Mg, and Acro Tips

Discussion in 'Coral Health' started by Ryland, Jan 17, 2012.

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  1. Ryland

    Ryland Stylophora

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    Ive recently been having some issues holding my alk at stable levels. Slowly over the course of a couple of weeks my alk has dropped from a stable 10.5 to my current level of 7.5 dkh. I am not sure what is causing this. All corals appear okay except I noticed tonight my blue Acro seems to be losing a small amount of tissue on 3 of its tips.

    I run kalkwasser and have a regular regimen of water changes. Water changes usually hold a dkh of 10.

    I was having issues with my Mg at low levels approximatley 900. Water changes brought it up to around 1050. I have since been dosing to bring the Mg up with mag sulfide and mag chloride at the mixture of 7 1/4 mag choloride to 3/4 mag sulfide. This has been done over 2 weeks to bring my Mg up to 1300.

    Is this alk burn on the tips of the Acro? If so, should I bring the alk up and how high should I hold it? Could the tip burn be due to the Mg increase? I did it slowly over about a week and a half. Should I be concerned that when I do water changes the new water has a dkh of about 10? This is a rather large difference between 7.5 and 10 dkh.
    Current levels
    Ph 8.1 steady
    Cal 460 steady
    Mg brought up to 1300 from 900 over 2 weeks
    Alk dropped from 10.5 to 7.5 in the last 3 weeks.
    phos 0
    nitrates 0
    nitrite 0
    Am 0
    Sg 1.024

    Thank you all ;D
     
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  3. Ryland

    Ryland Stylophora

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    PS. What could be causing the drop in Alk? What is the best Alk level to hold? Thanks
     
  4. steve wright

    steve wright Super Moderator Staff Member

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    aside from the additions you made to correct the low levels , are you dosing on a regular basis now?

    you list a number of SPS corals in your signature and growth of these in particular can account for drops in Calcium and Carbonates (dkh)

    Are you vodka, vinegar dosing or running pellets ? if the answer is no, then running and maintaining a dkh of 10, so that it is the same as your freshly made saltwater would be ideal IMO as that avoids any fluctuations

    how much water do you change at water change time? the lower the percentage the less effect the difference has changing 10% of the water with 10 dkh in a tank where the other 90% has a dkh of 7 means your tank would only increase to 7.3 ( 9 x 7 +10 divided by 10 = 7.3)
    thus not much of an issue IMHO

    did you make the recent additions into the DT or into the sump? because focused additions of supplements like Alk or Kalk into the DT where localised changes can be extreme, can cause issues like burned tips on SPS corals ( know this from when I dosed using mineral water bottle with alk supplement and airline drip, the coral closest to the point the airline entered the DT developed this issue)

    1300 mag is a bit low still IMO and it may give you issues maintaining calcium and alkalinity at your chosen targets
    with 460 ppm calcium you may find your alkalinity is harder to maintain at chosen value due to lack of Magnesium acting as binder

    I would target 1380 - 1450 for your Mag ( taking 48 hours to get there, no harm going slower than generally suggested IMO , although you can increase by up to 100pm in 24 hours )
     
  5. Ryland

    Ryland Stylophora

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    I chose to raise the Mg very slowly over 2 weeks as quick changes have haunted me in the past. I shoot for no more than 50 ppm change in Mg in a 24 hour period. Thanks again for you response
     
  6. Ryland

    Ryland Stylophora

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  7. steve wright

    steve wright Super Moderator Staff Member

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    Sorry Ryland it was lunch time for me

    Kalkwasser is a balanced additive, which should be adequate to supplement both calcium and alkalinity

    what ratios are you using it ( 2 teaspoons per gallon?)
    the suitability of this as a supplement on its own will depend on your evaporation or amount of this you can get into your system
    many people do need to use a combo of kalk plus 2 part calcium and alkalinity supplements when demand exceeds ability to supply via kalk alone

    15 - 20 gallons in a 125 + sump is around 10% and as such your alk level in water change water will not adversely effect your overall dkh

    ideal parameters - not sure such a thing exists
    your fine with an Alk between 7 and 11 in general
    your fine with Calcium between 380 - 450 in general

    obviously if you target the higher end of both of those values, you will need to ensure your magnesium is capable of supporting them otherwise you add one to the detriment of another

    you may not yet have exhuasted your kalkwasser potential, as the lower mag you before may have prevented some of the calcium/ carbonates staying in solution

    so once the mag is where you want it , continue the kalkwasser additions and measure to check it is keeping up with demand

    if not, yes you can use any typical alkalinity builder and combine with calcium supplement
    as required to maintain levels should kalk alone not be adequate.

    you may need to relocate the acro at least on a temporary basis whilst making and large supplement additions , but under normal circumstances as you are just adding maintenance supplement to the sump Via Kalkwasser , it will be diluted in the sump and as such does not pose much of a problem
     
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  9. Ryland

    Ryland Stylophora

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    Should the tip burn continue should I begin a regimen to raise my Alk levels? There is conflicting information on this on the web. Thank you again sir.
     
  10. Ryland

    Ryland Stylophora

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    Bump once more
     
  11. steve wright

    steve wright Super Moderator Staff Member

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    Your using kalkwasser at about half of its maximum strenght
    which may explain the Alk drop ( you probably also had a balanced drop in calcium, but that is harder to measure on test kits as in actuality calcium can drop by as little as 7ppm for every 1DKH drop)

    and if you tested 460 and next week it was 450, most people myself included would dismiss this as user variation/ interpretation of test result

    you could saturate your kalkwasser solution, with 2 teaspoons per gallon of RODI
    this may may increase your levels over a period of time, so testing weekly at minimum is a good idea

    you can always add a measured amount of the saturated solution each day , rather than replacing all evap water with kalkwasser

    you could also consider increasing your current 5 teaspoons per 6 gallons to 8 teaspoons per 6 gallons and see if at that strenght you can maintain parameters by replacing all evap water with kalkwasser top off

    Alk burn is often a reaction to elevated Alk levels rather than decreased Alk levels
    so the trick is not to increase by to much in any 24 hour period, and to spread whatever addition you do make out

    how are you dosing Kalk ? is it on auto top off or manual top off ? as if its manual and into the sump, adding to much of that at any time and with that acro in flow path , may have caused the burn you experienced on the coral

    if you target 10 as your dkh for you set up (which is fine) then that way your parameters on new salt mix will be same as tank and thus you avoid any parameter swing with that ion

    people who carbon dose , liquid or solid are sometimes better off with lower DKH/ Alk ( because low nutrient or ultra low nutrient systems can limit the amount of coral flesh that grows, in which case you do not want growth of skeleton to be in excess of the growth of flesh - think of it as bone growing through your fingers due to your flesh not getting enough nutrition to grow at the same pace )

    as you are not carbon dosing , running a level of 10 dkh is a reasonable solution to your concerns about Alk swings when making larger water changes

    just keep in mind that unless your mag level can support your desired Calcium and Alkalinity levels you may experience a swing / balance issue, which means when you increase one, the other drops and vice versa

    Steve
     
  12. evolved

    evolved Wrasse Freak

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    While Steve has definitely been steering you the right way, something I didn't see is if you're sure the tips are actually burnt. New growth on SPS will be white, which would also explain your Alk drop, if your SPS are growing fast enough to be using more Alk/Ca than what you're putting in.