Magnesium in tap water

Zeus.

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@Zeus. If you recall my earlier posts ( maybe a different thread I cannot remember ) I was suffering problems with my hygrohila 53b, hygrohila Compacta and hygrohila araguaia suffering pin holes, pale colouration (N/mg/Fe/K defiency symptoms,) staghorn algae and to soon end up with no growth and leaf drop but the one species you keep mentioning is hygrohila and its the one species I've had problems with maybe its a coincidence?. My java fern was growing,HC was growing but these was still experiencing pale growth and staghorn. Since adding the extra mg and k ( K2SO4 ) all my plants have coloured up and all plants have began to grow again although slowly. Staghorn has gone and not reappeared but its early days. I tried adding extra Fe in the form EDDHA, extra no3,extra po4 but no joy only until I added extra magnesium and k adjusting to these ratio's.maybe its species related or maybe there is something that we and our inferiors are over looking?
Your experiences also fit 'Liebig's law' also, the ratio link 'may be' just coincidental as T Barr surggests

Maybe Fe EDTA would be OK too in our tanks!!! but need to see recovery first before I try ;)
 

Witcher

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So how much (more) mgso4 are you guys adding in total? I'm going to double my dose and see if that helps.
@Sammy Islam I keep/add approx. 1.6ppm Mg either for the whole volume of the tank or for the volume of water changes and approx 5mg Ca (appr. 0.8 kH/1GH calculated). Generally I keep water hardness really low. Struggling with some algae but they are the effect of couple mistakes happened 2 months ago and don't seem to be related with my fertilization regime in general, actually they slowly disappear without almost any input from my side (however I keep PO4 quite high in relation to NO3: 1.5ppm PO4 to 5ppm NO3 weekly). Haven't seen any yellowing related to lack of Mg for months, occasionally I see stunted/deformed new leaves on A. Reineckii - usually after water change and also occasionally slight NO3 deficiencies (small melting of leaves etc.)

Hi Folks,

If you haven't already seen the following thread on another forum, it makes for very interesting reading. I really like the very detailed account of everything that 'kekon' did. Very methodical. Note the date of the thread!

https://www.aquaticplantcentral.com/forumapc/fertilizing/41779-how-balance-npk-ca-mg-micros.html

JPC
Hey @jaypeecee I must admit that I'm surprised that after so many years someone still quotes kekon's experiments - it was always good, very detailed source of info for me.
 

jaypeecee

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Hey @jaypeecee I must admit that I'm surprised that after so many years someone still quotes kekon's experiments - it was always good, very detailed source of info for me.
Hi @Witcher

You've obviously seen kekon's experiments before. Pretty impressive, eh! It would be good to follow up on kekon. I wonder if s/he is still around on that forum. Will check that out later.

JPC
 

Zeus.

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Hi Folks,

If you haven't already seen the following thread on another forum, it makes for very interesting reading. I really like the very detailed account of everything that 'kekon' did. Very methodical. Note the date of the thread!

https://www.aquaticplantcentral.com/forumapc/fertilizing/41779-how-balance-npk-ca-mg-micros.html

JPC
Had another read and his result fit the Liebig's law better than they fit the ratio IMO Plus he was adjusting the [Ca] as well as the [Mg] which happened to fit in the 4:1 ratio, he was also concerned about Mg excess so

Quote ' change: because of slight Mg excess i reduced it to 8 ppm. Also Ca was reduced to 32 ppm.' Unquote

So If I was to follow though on the ratio suggested Ca:Mg 4:1 with my tap water being 131ppm Ca I would need to add Mg to reach 32 ppm and he was concerned when his Mg was at 10ppm - would he of been concerned about a level of 32ppm Mg to fit with his Ca:Mg 4:1 ratio!!!!

This Ca:Mg:K may work fine with tanks with soft water to start with, but the maths and resulting ppms just end up being silly if you have hard water and conman sense tells you a 32ppm Mg is OTT :rolleyes:

Clive posted two replies in a pm some time back that gave his thoughts IMO to these related issue and advice from folks 'experimants'/advice/findings

Mate, whenever someone shows me a spreadsheet or some on-line calculator I always feel a wave of nausea. I mean, really, why all the calculations? For your size tank why not just dump 2 teaspoons KNO3, 1 teaspoon of KH2PO4 3X per week and 1 teaspoon trace 2X per week. End of story. Ifyou think you need Mg then just toss a couple teaspoons of the Epsom Salt in at water change. This is science, but it doesn't have to be Rocket Science. I just use the 2:1:1 rule and call it good. i don't even look at those stupid spreadsheets. It's just so energy sapping.
Yeah, coincidences happens a LOT in this hobby. That's what makes everyone so crazy...
So after

but dumpped 100g of MgSO4.7H2O in 500l tank this morning.
Doing WC ATM to bring [Mg] down to EI suggested levels - as I 'think I went from not enough Mg to too much Mg :nailbiting: - what was I thinking :rolleyes:
 

Oldguy

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UK tap waters tend to be low in Mg compared to Ca but there are many local variations. The big water companies tend to blend water to reduce hardness and maintain supply to a growing customer base. [My home town was liquid rock from bore holes but is now blended with river water and is much softer]

For amusement I have been looking at the labels on bottled water [typical analysis]
S.Pellegrino Ca 164ppm, Mg 49.5ppm, K 2ppm, Sr 2.7ppm.
Harrogate Spring Water Ca 45ppm, Mg 14ppm.
Chase Spring Water Ca 37ppm, Mg 11ppm, K 2.5ppm. (Aldi small bottles)
Chase Spring Water Ca 38ppm, Mg 12ppm. (Asda 17p for 2 litres) its my favorite*.

High Mg content is a laxative and has caused jipy tummy to holiday makers avoiding local tap water and drinking bottled 'spa' water. It also founded health resorts/spas.

As plant growers we jack up nitrates, phosphates and potassium and trace elements together with carbon dioxide but tend to forget about magnesium. (gardeners throw it about as the sulphate with gay abandon). I do not believe that tight ratios of this to that really matter, unless its about dry martinis. Commercial fertilizers are in ratio to give good growth at minimum cost to most plants in most situations.

I am wary of high levels of Ca and Mg ions on the stability of iron and trace element chelates. Therefore I run a 'soft water' tank. Where I now live the tap water is moderately soft and I mix this with rain water and bring the hardness back up to moderately soft with magnesium sulphate. I assume there is little or no Mg present before I make my addition. I also boost the potassium level at water change. After that its IE till the next water change

* also add Asda fizz at water change time to quickly bring the dissolved CO2 back up to the level it was before the weekly 50% change. Always watch the fish.
 

jaypeecee

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Hi @Oldguy

Isn't it interesting that the Ca to Mg ratios for all the bottled waters you have listed are very close to the oft-quoted figure of 3:1? Coincidence? Maybe. Also, to what concentration do you "boost the potassium level at water change"? And, forgive me, what is "IE"?

JPC
 

jaypeecee

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Yes the ratios are a very good fit. I use this ratio with regard to water analysis in general, however tap water can be lower. Bottled water typically comes out of dolomitic limestone. Potassium boost - about 10ppm. IE should be EI Estimated Index. Dyslexia lures KO.
Hi @Oldguy

Many thanks. :thumbup:

JPC
 

Zeus.

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Yes the ratios are a very good fit. I use this ratio with regard to water analysis in general, however tap water can be lower. Bottled water typically comes out of dolomitic limestone. Potassium boost - about 10ppm. IE should be EI Estimated Index. Dyslexia lures KO.
Thing is I'm Dyslexic so I just read it as EI :lol:
 

Zeus.

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Came across one of @ceg4048 aka Clives posts NPK what ratio

Quote
EI dosing schemes are based on "infinite availability" of individual nutrients, not on ratios of nutrients. Each of the species and each specimen has it's optimum uptake based on current environmental conditions so that for example Alternanthera may use more phosphates than Anubias simply because it's production of fuel requires more. HC may uptake more Carbon than Java Moss simply because it's native environment may require it to a greater extent. There is no ratio or even uptake rate that can be unilaterally applied.
Unquote.

Shame he isn't active ATM as I for one would love to see his input on this Ca:Mg and Ca:Mg:K ratio :angelic:

When you have a lot of Ca++ ions the next “taxi” on the rank is much more likely to be a Ca++ ion, rather than a Mg++ ion,
Which makes sense esp when the body of water is static as diffusion being x10000 slower in water, However with our turnover rates being X5 for low tech and x10 for high tech this should IMO help compensate things as the 'Taxis' are passing by so quick.
 

Witcher

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EI dosing schemes are based on "infinite availability" of individual nutrients
Does it means that we can pour 50 ppm of N, 50 ppm of K, 50 ppm of Fe, 50 ppm of B, 50 ppm of Mn and plants will selectively choose whatever they need?
 

Zeus.

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Does it means that we can pour 50 ppm of N, 50 ppm of K, 50 ppm of Fe, 50 ppm of B, 50 ppm of Mn and plants will selectively choose whatever they need?
Yes/NO - IMO as some of those ppm would probably be fatal to the plants and livestock, but if you had chosen some sensible ppms for some of the elements YES

Liebig's law up to the toxic threshold for each element
 

Wookii

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This is an interesting thread. I live in a relatively hard water area (Nottingham).

I am EI dosing using the APFUK salts, part of which is Magnesium Sulphate (MGSO4).

Are you guys saying that because of your hard water, you need to dose even more MgSO4 than the standard APFUK mix?
 

jaypeecee

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Hi Folks,

Now, I'm flummoxed! Are we now dismissing the idea of an optimum Ca:Mg:K ratio being provided in the aquarium water?

JPC
 

Zeus.

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Are you guys saying that because of your hard water, you need to dose even more MgSO4 than the standard APFUK mix?
Well seeing your using EI dosing the best person to ask is T Barr (who came up with EI Dosing) - I've spent some time over at the Barr report this week and in the posts I read about the Ca:Mg ratio Tom was very dismissive about a Ca:Mg ratio basically saying ignore the ratios and use Liebig's law so the range suggested for Mg in our tanks is 5 to 10 ppm per week and ignore your [Ca] as Calcium deficiency is very rarely seen.

Are we now dismissing the idea of an optimum Ca:Mg:K ratio being provided in the aquarium water?
Well I am dismissing the idea of an optimum Ca:Mg:K ratio - as I have seen little if anything to convince/support the idea that there is one.
Plus if I followed the Ca:Mg:K ratio 2:1:0.5 at my present weekly [K] of 30ppm I would need to increase my [Mg] to 60ppm to fit /suit my tap water being 121ppm Ca :eek:
 

jaypeecee

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FWIW, I do know that Tropic Marin in their Re-Mineral Tropic RO salts formulation uses three times more Ca than Mg.
 

Zeus.

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FWIW, I do know that Tropic Marin in their Re-Mineral Tropic RO salts formulation uses three times more Ca than Mg.
I take it its used for Remineralising water thats been though an RO unit ? and so the Ca:Mg ratio is 3:1 ! do they suggest to add enough to yield a [Ca] of 120ppm ! I doubt it so why should I follow the 3:1 ratio and get my Mg to 30ppm as my water has 121 ppm Ca ;) the EI range for Mg per week is 5 to 10ppm Mg
 

jaypeecee

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I take it its used for Remineralising water thats been though an RO unit ? and so the Ca:Mg ratio is 3:1 ! do they suggest to add enough to yield a [Ca] of 120ppm ! I doubt it so why should I follow the 3:1 ratio and get my Mg to 30ppm as my water has 121 ppm Ca ;) the EI range for Mg per week is 5 to 10ppm Mg
Hi @Zeus.

Correct, it's a remineralizer for water that's been through an RO system. When made up according to their guidance notes, I get Mg = 8 - 10 ppm, K = 15 - 20 ppm and GH = 7.5 dH. Plugging these figures into the calculator at www.flowgrow.de/db/calculator/magnesium, I get Ca = 37 ppm. So, this would mean Ca:Mg:K is 4:1:2. o_O Very odd. Perhaps Tropic Marin (aka TMC) don't know how to formulate remineralizers for use with planted tanks? I haven't got back to them yet with my measurements but I'll do that soon. I know it's a contentious issue but I used JBL test kits to do the Mg and K measurements plus API test kit for the GH.

JPC
 

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