# Mg defiency, how much to dose?



## plantnoobdude (24 Aug 2021)

At the moment I'm fairly sure my tank has an Mg deficiency. I'm dosing 7ppm during my weekly water change with pure RODI water. none added during the week. my tank shows slow growth and crinkly leaves in certain plants, ludwigia palustris and the hygrophila polsyperma I added as an indicator plant. I have decided to up Mg to 10ppm during my weekly water change. Ca will be 30ppm and Mg will be 10ppm from next week.gh will be 6.3 if that fails I may start supplimenting Mg during the week via a separate solution. my question is how much should i start with, 3ppm? 10ppm? i can't find any info online. would trial and error be the only way? cheers


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## dw1305 (25 Aug 2021)

Hi all, 


plantnoobdude said:


> I'm dosing 7ppm during my weekly water change with pure RODI water.


That should be plenty. Which leaves are pale? Old or new?

cheers Darrel


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## plantnoobdude (25 Aug 2021)

none are pale. though the crinkly leaves affect all of the plant. which is why i thought of magnesium. @dw1305


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## Zeus. (25 Aug 2021)

Are you using CO2 injection? if so have you done a pH profile and what colour is the DC (Drop Checker)

What fert are you using or what levels are you dosing?


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## plantnoobdude (25 Aug 2021)

Zeus. said:


> Are you using CO2 injection? if so have you done a pH profile and what colour is the DC (Drop Checker)
> 
> What fert are you using or what levels are you dosing?


yes high co2 injection. over 30ppm drop checker is a nice yellow/green colour all throughout photo period. Have not done a ph profile but i don't think it's a co2 issue as i have good flow through the tank. with no dead spots.
dosing is EI
30ppm No3 per week
20ppm K per week
3ppm Po4 per week
0.4ppm Fe per week


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## MrClockOff (25 Aug 2021)

I would definitely check pH profile. The ferts dosing is looking spot on. Depends on how much light you have so current CO2 injection might be not enough. By the way it does look like CO2 issue


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## plantnoobdude (25 Aug 2021)

MrClockOff said:


> I would definitely check pH profile. The ferts dosing is looking spot on. Depends on how much light you have so current CO2 injection might be not enough. By the way it does look like CO2 issue


I dont feel comfortable with bumping the co2 up even more. drop checker is yellow by the end of the day. also have plenty of flow, about 800lph (factory suggested). also don't have a ph pen and my liquid test kit does not go low enough (it stops at 6)


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## MichaelJ (25 Aug 2021)

plantnoobdude said:


> yes high co2 injection. over 30ppm drop checker is a nice yellow/green colour all throughout photo period. Have not done a ph profile but i don't think it's a co2 issue as i have good flow through the tank. with no dead spots.
> dosing is EI
> 30ppm No3 per week
> 20ppm K per week
> ...


@plantnoobdude,  If not a CO2/flow/light issue, I think I've read somewhere, that it could be a key mineral deficiency issue, specifically Ca, which should probably be around 30ppm if your dosing 10ppm Mg.


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## MrClockOff (25 Aug 2021)

plantnoobdude said:


> I dont feel comfortable with bumping the co2 up even more. drop checker is yellow by the end of the day. also have plenty of flow, about 800lph (factory suggested). also don't have a ph pen and my liquid test kit does not go low enough (it stops at 6)


Well depends on what test are you using but if that is API PH then the increments between colors are too big and also I found that some colors just look exactly the same on the chart. Also comparing my API PH result with my PH pen result the difference was 0.4pH which is way too big error..
Two things:

800lph but what is the tank water volume
pure RODI for WC? Are you remineralising it?


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## plantnoobdude (25 Aug 2021)

MrClockOff said:


> Well depends on what test are you using but if that is API PH then the increments between colors are too big and also I found that some colors just look exactly the same on the chart. Also comparing my API PH result with my PH pen result the difference was 0.4pH which is way too big error..
> Two things:
> 
> 800lph but what is the tank water volume
> pure RODI for WC? Are you remineralising it?


45l tank. remineralised to 21ppm Ca and 7ppm Mg or so. raised to 30ppm:10ppm ca;mg yesterday.


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## plantnoobdude (25 Aug 2021)

MichaelJ said:


> @plantnoobdude,  If not a CO2/flow/light issue, I think I've read somewhere, that it could be a key mineral deficiency issue, specifically Ca, which should probably be around 30ppm if your dosing 10ppm Mg.


yes, i doubt it's a co2 issue, because the more finnicky plants are doing just fine. Ca is at 30ppm per week at wc now,


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## MrClockOff (25 Aug 2021)

plantnoobdude said:


> 45l tank. remineralised to 21ppm Ca and 7ppm Mg or so. raised to 30ppm:10ppm ca;mg yesterday.


In this case I can only think that either or all together:

water temp to high or to low (22-24c is recommended)
Light/CO2 injection rate imbalance
Distribution issues
plant is still transitioning/adapting


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## Zeus. (25 Aug 2021)

plantnoobdude said:


> yes high co2 injection. over 30ppm drop checker is a nice yellow/green colour all throughout photo period



But no pH profile ! The main cause of issues in a CO2 injected tank is CO2 related or flow, the DC colour change is historical and only gives a rough indication. If pH is taken with a decent pH pen or papers from CO2 on every 30mins and lights on till CO2 off then we can rule out stable pH issue but not flow.

Pointless looking for rare causes until you have ruled out the main culprits CO2 and Flow 

Don't think is Ca or Mg, as T Barr points out hes never seen a Ca related issue even with low Ca in water.

Could do with a Full tank shot and all tank details lights pumps filters etc


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## plantnoobdude (25 Aug 2021)

MrClockOff said:


> In this case I can only think that either or all together:
> 
> water temp to high or to low (22-24c is recommended)
> Light/CO2 injection rate imbalance
> ...


temp is 23. light is very high and co2 aswell. the ludwigia palustris has shown this issue for a while. hygrophila polysperma is new to this tank but i can't see that affecting it to be honest.


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## plantnoobdude (25 Aug 2021)

looking up images of terrestrial plants with Mg deficiency and they seem pretty similar. to what i see in my tank














						Magnesium Deficiency In Plants
					

Magnesium deficiency in plants is easy recognise and prevent prevent by using the correct nutrient solution every time you water your plants| Bio Leaf Plant Nutrients, New Zealand




					www.bioleaf.co.nz
				











						Importance of Magnesium for Man, Plant, and Soil - Nutri-Mg
					

Magnesium’s Impact on Vitamin D Intake




					nutri-mg.com


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## plantnoobdude (25 Aug 2021)

Zeus. said:


> Could do with a Full tank shot and all tank details lights pumps filters etc





chihiros wrgb2 percentage 90:60:90 rgb
co2 : yes
tropica soil
eheim 2213+skimmer
23c temp
kh 0 
gh 4 (now raised to 6)
i don't have the funds to get a ph pen at the moment.


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## MichaelJ (25 Aug 2021)

plantnoobdude said:


> 45l tank. remineralised to 21ppm Ca and 7ppm Mg or so. raised to 30ppm:10ppm ca;mg yesterday.


That should be more than enough.  But better check on that CO2/flow situation, even if it appears good, as it seems to be the culprit for most high-tech tank issues by far.


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## MichaelJ (25 Aug 2021)

plantnoobdude said:


> i don't have the funds to get a ph pen at the moment.


How old is the tank?


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## plantnoobdude (25 Aug 2021)

MichaelJ said:


> How old is the tank?


1 year old


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## MrClockOff (25 Aug 2021)

plantnoobdude said:


> View attachment 173480
> chihiros wrgb2 percentage 90:60:90 rgb
> co2 : yes
> tropica soil
> ...


Can't see the CO2 diffuser. Is this inline injection?


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## plantnoobdude (25 Aug 2021)

sort of. it's on my filter output @MrClockOff


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## MichaelJ (25 Aug 2021)

plantnoobdude said:


> 1 year old


Unless you recently trimmed it down considerably, and considering this is a CO2 injected tank, I would have excepted way more growth from these plants after a year.


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## plantnoobdude (25 Aug 2021)

MichaelJ said:


> Unless you recently trimmed it down considerably, and considering this is a CO2 injected tank, I would have excepted way more growth from these plants after a year.


it's been trimmed countless times haha. this is after full replanting a week or two ago.


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## MichaelJ (25 Aug 2021)

plantnoobdude said:


> it's been trimmed countless times haha.


OK Good .. it kind of looks like it was planted week ago 



plantnoobdude said:


> this is after full replanting a week or two ago.


Ok, that piece of info might be helpful for the experts... I might suggest that the plants are just adapting after being replanted and you just need to wait it out a bit. ... but checking into the CO2/flow situation never hurts.


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## MrClockOff (25 Aug 2021)

plantnoobdude said:


> 1 year old


Not much grow for one year


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## MrClockOff (25 Aug 2021)

plantnoobdude said:


> sort of. it's on my filter output @MrClockOff
> View attachment 173481


Ha never seen that before. Can you see loads of CO2 bubbles at the substrate. Bubbles may all escape to the surface and not reaching the substrate


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## plantnoobdude (25 Aug 2021)

MrClockOff said:


> Ha never seen that before. Can you see loads of CO2 bubbles at the substrate. Bubbles may all escape to the surface and not reaching the substrate


can see bubbles all the way around the tank. pointed downwards so it gets to the substrate well.


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## MrClockOff (25 Aug 2021)

plantnoobdude said:


> can see bubbles all the way around the tank. pointed downwards so it gets to the substrate well


You've said that you did replanting a week ago. Is that the time when problems started or did that started long time ago?


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## plantnoobdude (25 Aug 2021)

MrClockOff said:


> You've said that you did replanting a week ago. Is that the time when problems started or did that started long time ago?


a while ago,


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## John q (25 Aug 2021)

Just an observation from your journal My 12G softwater which I assume is the same tank? In the last 3~4 weeks you seem to have changed from a lily pipe on the left, to a spraybar and now with your current outlet setup, maybe this inconsistency is contributing to the problems you're having. BTW this is just me thinking out loud.


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## plantnoobdude (25 Aug 2021)

John q said:


> Just an observation from your journal My 12G softwater which I assume is the same tank? In the last 3~4 weeks you seem to have changed from a lily pipe on the left, to a spraybar and now with your current outlet setup, maybe this inconsistency is contributing to the problems you're having. BTW this is just me thinking out


not practicing what I preach. I see 🤣. I always say consistency is the key to healthy plants. I'll keep that in mind. thanks!


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## plantnoobdude (2 Sep 2021)

small update. upped magnesium from 7ppm-10ppm. and started dosing mgso4 during the week as well. didn't change anything else. already see improvement.


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## MichaelJ (2 Sep 2021)

plantnoobdude said:


> small update. upped magnesium from 7ppm-10ppm. and started dosing mgso4 during the week as well. didn't change anything else. already see improvement.View attachment 173799


@plantnoobdude  Definitely progress - Very nice!  your Mg content must have been very low.

Edit: here is the post by @dw1305 re Mg content of NW Europe water: Magnesium content

Ok, your using pure RODI water so the above is not relevant for your situation, but still interesting for people using tap water and encounters a similar problems caused by Mg deficiency.

Cheers,
Michael


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## plantnoobdude (2 Sep 2021)

perhaps the demands of a high-tech tank were higher than I thought. After all magnesium is a secondary macro nutrient.


MichaelJ said:


> Edit: here is the post by @dw1305 re Mg content of NW Europe water: Magnesium content
> 
> Ok, your using pure RODI water so the above is not relevant for your situation, but still interesting for people using tap water an encounters a similar problems caused my Mg deficiency.
> 
> ...


thanks for the nice read!


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