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Balancing Calcium and Magnesium

Discussion in 'Aquatic Plant Fertilization' started by grshs_vny, May 23, 2011.

  1. grshs_vny

    grshs_vny Prolific Poster

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    I have question for Tom ,my tap water has more magnesium(17ppm) and less calcium(16ppm) is this the issue causing leaf bending downwards ?I know your first thought is carbon dioxide but i tell you it is adequate (around 25ppm), PO4 around 1-2ppm.I am not complaining about growth but about appearance.I have heard many folks saying nitrate,boron and even iron as the culprits but i am not convinced.Whats your opinion?
     
  2. dutchy

    dutchy Plant Guru Team
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    Although I'm not Tom, I think I can give you an answer.

    People blame nutrients all the time, but it's very easy to rule it out, just add enough. If you always add enough, as in EI, you don't even have to think about nutrients causing your problem. Then what is left? CO2.
    How can you be so sure your CO2 level is around 25 ppm? If you can't do in-situ measurements, it's just an assumption. pH/KH table? 0,1 off on your pH measurement = 10 ppm more or less. Dropchecker? How can you equal colour to 25 ppm? And then, who says that 25 ppm is enough? Maybe in your tank, you need 30....or 40 ppm. CO2 ppm's vary from minute to minute, depending of a lot of different parameters in your tank.

    Difficult, isn't it?

    I"ve seen no adverse effects in plants with a lot of different Ca/Mg ratios, and I've done 4:1 to 1:1. Maybe toxic levels could lead to problems ,but our tapwater is never in that toxic range.

    Magnesium can be toxic at low concentrations , but toxicity is dependent on Ca concentrations and doesn't show up until 1:9 Ca/Mg ratio.
    http://onlinelibrary.wiley.com/doi/10.1002/etc.56/abstract
     
  3. Tom Barr

    Tom Barr Founder
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    You still get good growth at suboptimal CO2.........I think folks tend to think of this as an on/off switch, growth increases non linearly at the CO2 concentration increases.

    You can add CaSO4 to raise Ca++........I'd add about 1/2 teaspoon per 50 Gal, that should address any issues for Ca++.
    My CO2 sits about 45-50 and up to 70-80 in other tanks but that's calibrated measurement.

    When folks say 25ppm, I really do not know, nor do they.....if that is the case.
    There's nothing to compare it to for a reference for the measurement.

    So it's a guess.
     
  4. dutchy

    dutchy Plant Guru Team
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    I've had Ca. as low as 8 ppm and Mg. as low as 2 ppm without any deficiency signs like chlorosis etc.
     
  5. grshs_vny

    grshs_vny Prolific Poster

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    Am sure both of you have the expertise so i consider CO2 again.I use both drop checker and pH ,KH table.
    This one is interesting.
    I'll make a note of it.
     
  6. grshs_vny

    grshs_vny Prolific Poster

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    But dutchy i have the reverse of that you had ,i mean even though you had 8:2 you can raise it to what you desire but in my case it is 16:17.


    O.k still i have hope
     
  7. Tom Barr

    Tom Barr Founder
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    Alright.........look at the ppm's from the West side of Davis wells:
    http://cityofdavis.org/pw/pdfs/SummaryofallWells.pdf

    Low Ca, high Mg.

    Here's my aquarium:
    [​IMG]

    [​IMG]

    Now if I can grow these plants at 1/2 the levels in the report...............(I diluted with 50% RO for water changes), my Mg was around 25ppm........the Ca was -18-20ppm.
    The tap I have now is about 15ppm Ca and 2-3ppm Mg.

    I find little difference, the coloration for many plants was better in the harder GH water.

    In Santa Barbara, the Tap was mostly Ca++ and very little Mg.
    No RO blended there.
    82 Ca++ and 30-35ppm for Mg++
    KH was 11-12

    No issues.

    Maybe it has much much much more to do with CO2 management and assumptions and virtually nothing to do with ratios or low Ca/Mg levels...........?????????

    Given ther lack of controls and testing, and the evidence that these ratios and ppm's have little real comparative argument otherwise...........it would seem it's a CO2 issue.
    I've not seen any conclusive evidence that Ca and Mg play much role in crops and aquarium plants for that matter. It might be an issue when folks limit Mg, which seems to be far more common than Ca++ , but the ratios play little role.
    There is no factual basis for most of the claims made regarding this.

    CO2?

    Lots and lots.........

    I do not think any researchers would note much ecological pattern changes due to Ca/Mg ratios, or that above a limiting level....that plants can/cannot grow or anyone that's shown Ca++ limitation in aquatic plants.
    We have massive weed infestations in Lake Tahoe, which is a hyper oligotrophic lake, they are not limited by the low ca and Mg........they grow just fine.
    12 ppm and 2ppm for Ca and Mg. Such lakes are pure snow melt, so they have little Ca and Mg. In Rainforest, the recycling of Ca and Mg from decomposing plant material and from sediments is high, but gets used and bound rapidly.
    Borneo :
    http://upm.academia.edu/AhmadZaharinAris/Papers/81374/A_pristine_environment_and_water_quality_in_perspective_Maliau_Basin_Borneos_mysterious_world

    Much much higher.

    You can poke around a look for Ca and Mg levels in other regions where plants might be.
     
  8. grshs_vny

    grshs_vny Prolific Poster

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    O.k Tom after your last reply am concentrated towards CO2.Previous day I did a massive water change and noticed pygmy sword skeletonized and melting from bottom(crown).

    Here is the story, actually my tap water is 44ppm Ca and 17ppm Mg ,being an inexperienced enthusiast i started assuming things as most beginners do.Bugged by rigid ratio idea , started adding Ca to match ratio but no success,tried using 60% RO water to reduce both Ca&Mg but unfortunately things didnt worked somehow my rescaped tank started leaching Mg(may be from stirred up ADA AS?/Penac P?)and never fell below 17mg,the only thing lowered is Ca from 44 to 16-18ppm.After your suggestion i stopped everything and making things simple by using only tap water ,this whole time KH started swinging i have read somewhere instable KH results in skeletonized sword .Is this true?

    The current Ca is 44 & Mg 17 .Am dosing 10ppm NO3 ,10ppm K,5ppm PO4 ,1/b tsp trace+Fe.Do i need any more Ca/Mg?
     
    #8 grshs_vny, May 27, 2011
    Last edited by a moderator: May 27, 2011
  9. Tom Barr

    Tom Barr Founder
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    This is still fairly high, you need to get to less than 3-2ppm before any issues might show up.......
     
  10. Tom Barr

    Tom Barr Founder
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    As I stated prior, you need CO2.

    Sword plants, the entire genus are extremely tough and resilent weeds.
    You also have plenty of Ca/Mg in the soil.
    The plants are not even remotely close to having any issues with the ferts there.

    This is a CO2 issue, perhaps too much light etc.
    Make sure you have good ample current so you do not gas the fish, then slow and progressively, maybe a tiny bit each 2-3 days with good careful observation........adjust CO2 up.
     
  11. grshs_vny

    grshs_vny Prolific Poster

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    update-


    Yes Tom, increased CO2 is working,you maynot belive am using 8-10bps, 16 watt 1000ltr/hour powerhead above disc diffuser to achive target in my 25 gallon tank.am using plain tap water,which is 33ppm Ca and 24ppm Mg,am not adding any more Ca & Mg and simply dosing according to EI.

    Now back to the topic,i have seen few posts in which you mentioned Mg above 20 ppm may have toxic effects,my rotala nanjenshan is growing with tiny leaves and leaves immediately next to the tip is lookig brown,even HC which is newly planted showing brown colouring. my trace is high on Zn(4%) is this causing brown or bronzing?????????rotala roundifolia is losing its red colour with few scalple marks on leaves, ithink am bit high on lights 125watt VHO t5,i will try reducing it.

    when you mentioned west area of davis wells,which well you mean?

    Anyways CO2 is really helping, i thank you ,but still need your help to resolves this problem.
     
  12. Tom Barr

    Tom Barr Founder
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    I do not KNOW there is any toxic effect to higher ppm's of Mg to a specific plant species.

    I know what I have done...........but the plants might be fine at much higher levels.

    Point is, the ratio matter very very very very little, if at all.

    I'd say the KH is more important and a factor.
     
  13. darkoon

    darkoon Prolific Poster

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    i am curious to know how many bps you had before, and what is your current estimated co2ppm by either ph decrease or by drop checker.
     
  14. Tom Barr

    Tom Barr Founder
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    BPS really does not say a whole lot, bubbles are different sizes after all..............

    I do not know what this means or not............I do know what poor CO2 effects on the tip growth does look like.

    Pics help.
     
  15. grshs_vny

    grshs_vny Prolific Poster

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    Exactly,dont get fooled by bps,it depends on bubble counter,diameter of the tube inside the counter.This is what confusing in the hobby ,when people 15 bps we think they gonna gas the fish but thats not the case.One of my chap running only 3bps
    but am nearly 12.I know its hard to count more than 7bps but i get 1bps in diffuser for every 3bps in counter provided all my tubing is leak proof.
    Tip curling is more to do with CO2 rather than Boron,Calcium etc.
    i'll update with results.
     
  16. grshs_vny

    grshs_vny Prolific Poster

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    Well,Tom, Am fully convinced its- CO2,no more tip curling now but i still have small leaves on rotala verticillaris, java moss seems stunted with terrible hair algae,hemianthus callitrichoides is melted but few tiny leaves sagging in the water current and small colony of BBA on spray bar but i should say its under control.Am reduced light from 54 watts to 30 watts(25 gallon tank) and again increased C02 with bit more surface agitation.Am really confused,now i feel its more a case of stability of the aquarium i don't know much about it.You mentioned in your earlier post about KH honestly i don't know much about it also,what i know is,it's just a measure of hardness of water due to carbonates and bi carbonates :confused:.

    Need help very badly.
     
  17. Tom Barr

    Tom Barr Founder
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    KH is alkalinity or for us, Bicarbonate hardness(- HCO3) mostly.

    A Simple KH test kit will help, and you can measure it and then get an idea of what it is.

    Google will help a lot here.

    I think good consistent CO2, less light and time will help. From there, it is a lot of trimming out of the algae and bad looking plants/parts of plants.
    Algae eating shrimp, fish etc often help a fair amount.
     
  18. grshs_vny

    grshs_vny Prolific Poster

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    O.K Tom ,did a search on google and got the point , meassured KH in my tank its around 6dKH, reduced light to 40W.Your posts are really helpful in building confidence, so today again i bought HC and this time i dont want to take any chances so do you have any suggetions regarding HC?
    My previous HC melted pretty quickly but still very few stems are hangin around with tiny leaves.

    waiting for your reply and thanks in advance.
     
  19. grshs_vny

    grshs_vny Prolific Poster

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    No improvements Tom.R.roundifolia,R.verticillaris are looking very bad,new growth is fully deformed and tiny ,HC is started looking like HM ,every morning leaves look horribly bent which recovers at the end of the photo period,i remember your post about this but don't know the reason for this.

    CO2?????
    now i can rule out CO2 cos i am running plants only tank,since i gassed all the fish i transferred to the NON-CO2 tank which is doing very good.

    RATIO????
    i can rule out this also cos ,as i said previously,i had pretty good growth for a brief time after your suggestion.
    But,

    thinking about that LITTLE ROLE.

    LIGHT??????
    this is where i had the problem,may be too much of light??????

    I have noticed all my tall plants,especially R.roundifolia,R.sp.green ,Hygrophila species having pale green color similar to Mg deficiency but without much dark veins during the photo period ,intense at the end of the night and becomes normal at the start of the photo period in the morning.

    so yesterday i decreased my T5 to around 24W. and waiting to see what happens.


    Now any one has any other idea?????????????????????????
     
  20. jaafaman

    jaafaman Prolific Poster

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    Have you checked nitrogen lately? It would seem that the carbon-nitrogen balance, rather than a Ca/MG concern, might be the problem, as they sound to be taking in N at a higher rate than the C will support...
     
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