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Mg defiency, how much to dose?

plantnoobdude

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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
IMG_2739.JPG
 

plantnoobdude

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

plantnoobdude

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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
 

MrClockOff

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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
 

plantnoobdude

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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)
 

MichaelJ

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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
@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

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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?
 

plantnoobdude

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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.
 

plantnoobdude

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@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,
 

MrClockOff

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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
 

Zeus.

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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
 

plantnoobdude

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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
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.
 

plantnoobdude

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plantnoobdude

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Could do with a Full tank shot and all tank details lights pumps filters etc
IMG_2736.JPG

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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