N concentrations vs dosing targets

[blairgerman]

I have seen it discussed that Nitrate concentrations measured in tank via test kits (ie: sera) is a very different type of Nitrogen, as available to plants, than Nitrate from ferts (ie: from Kno3) because the former is from organic origin (waste).

For this Tank Journal , I get 25ppm N but I am dosing about 1/5th the nitrate of EI per the calc.

Should I ignore the measured concentrations and only focus on fert targets?

This is important because phosphate concentrations in tank are 5ppm (maybe from food?), and I feel like that needs to be less (closer to 2) or at least not increased... BUT, if I increase N for my macros without increasing phosphate then I violate the ratio 3:1:3

Perhaps I should ignore tank concentrations all together?

 

[Nick potts]

I wouldn't put too much thought into ratios and absolute targets.

Go by what the tank and plants are telling you, are they showing any deficiencies, are they healthy, etc? I bit of excess ferts is 99% of the time not going to cause you any issues in an otherwise well-maintained tank.

 

[MichaelJ]

Should I ignore the measured concentrations and only focus on fert targets?

Yes, personally I would disregard what you measure with test kits and just go by what you dose. Dosing for certain targets and ratios is fine, but do not try to factor in NO3 and PO4 from organic waste buildup. If those numbers are in excess, its probably a good indicator you may be short on your maintenance (WC's).

Cheers,
Michael

 

[dw1305]

Hi all,

measured in tank via test kits (ie: sera) is a very different type of Nitrogen, as available to plants, than Nitrate from ferts (ie: from Kno3) because the former is from organic origin (waste).

Sort of, but all the nitrate ions (NO3-) are the same, it doesn't matter where they came from, but it does matter where they came from in terms of their usefulness as an indicator of organic pollution.

Oxygen (O) and nitrogen (N) are both <"highly reactive elements"> and have been combined into an infinite number of compounds <"during their 4.5 billion years on Earth">.

• The difference is between nitrate (NO3-) that is the result of the <"oxidation of ammonia in the tank"> in which case it is the <"smoking gun">, but not the bullets, they were the highly toxic ammonia (NH3) and nitrite (NO2-) that preceded it, and
• nitrate (NO3-) that was added <"via a chemical salt"> (like potassium nitrate (KNO3)) and has always been NO3- ions in the tank.

Should I ignore the measured concentrations and only focus on fert targets?

This is important because phosphate concentrations in tank are 5ppm (maybe from food?), and I feel like that needs to be less (closer to 2) or at least not increased... BUT, if I increase N for my macros without increasing phosphate then I violate the ratio 3:1:3

Perhaps I should ignore tank concentrations all together?

I agree with the others, just ignore <"the test kit results"> and the ratio.

Personally I don't add a set amount of nutrients. I use the <"leaf colour"> and <"growth rate of a floating plant"> (not <"CO2 limited">) as my <"proxy for nutrient content">.

I called it the <"Duckweed Index">, but my <"Duckweed"> of choice is now <"Amazon Frogbit (Limnobium laevigatum)">.

cheers Darrel

 

[blairgerman]

I wouldn't put too much thought into ratios and absolute targets.

Go by what the tank and plants are telling you, are they showing any deficiencies, are they healthy, etc? I bit of excess ferts is 99% of the time not going to cause you any issues in an otherwise well-maintained tank

This is exactly what I need to focus on, learning from you guys how to observe growth. I have been using this chart

but I know this is too basic. I am in the process of changing my micros already and will respond to that before I mess with macros so as to only change one factor a a time - I recently changed from EDTA chelated Fe to DPTA and fe gluc, so I need to get this sorted first. My ludwigia became krinkley, lost it's red, and smaller leaves, so I am assuming i need to increase my fe, which is now at .45 ppm.

This was ludwigia before changing my micros

, so I know the major change is due to my micros change, but the holes do indicate K deficiency and @Hanuman's calculator indicates my K is 1/3d where it should be (assuming I'm using the calc right).

New nanapettite growth is yellow and small. Xmas moss is spindly.

... Old growth of nanapettite was big and dark

The tank has some very big plant mass and by some calculations i think I am now dosing 1/3rd the fe (DPTA and gluc) as I was adding of EDTA fe - I'm not 100% sure, the numbers were hard to crunch cuz previous was CSM+B, this is my first DIY trace mix and I was just using targets from @burr740 and @slipfinger on another forum's dit micros thread. I'm going to triple traces and probably go ahead and triple K cuz how else would there be holes...?

 

[blairgerman]

Yes, personally I would disregard what you measure with test kits and just go by what you dose. Dosing for certain targets and ratios is fine, but do not try to factor in NO3 and PO4 from organic waste buildup. If those numbers are in excess, its probably a good indicator you may be short on your maintenance (WC's).

Cheers,
Michael

This makes sense then, I am at 50% per week, but not enough substrate siphoning because my hillstream are breeding and I am scared about where their eggs are being scattered, I only know the eggs go downstream. There are areas of malm which I have not touched. The PO4 is a concerning number for me. Now i understand that the benefit measured concentrations is for indicating waste buildup (as well as dosing). I will disregard these numbers when determining fert dosages.

 

[blairgerman]

the <"smoking gun">, but not the bullets, they were the highly toxic ammonia (NH3) and nitrite (NO2-) that preceded it

This entire reply is amazingly useful, I have been reading the cited posts and I'm learning so much. This addresses and explains every factor I need to monitor, change and learn more about, thank you so much. Knowing the meaning and etiology of N in the tank as organic pollution vs ferts is key. This will be the start of a major shift in my approach. I do think I need to start another tank to learn on with more controlled factors so I can properly observe and manipulate independent variables. Tanks such as in the micro mix threads I have read and @Hanuman journals would be better. I think this display tank is not the right setup for this. This will be my next step. But for now I will benefit from feedback about the deficiencies illustrated in the above pictures. I see a tank like this is proper for observing and understanding plant growth without confounding variables.

( @slipfinger). Adding frogbit asap, and would benefit from any feedback for the plant growth reported in the above reply to @Nick potts

Thank you so much @Nick potts @MichaelJ , and @dw1305 - this is clearly an amazing forum.

 

[_Maq_]

if I increase N for my macros without increasing phosphate then I violate the ratio 3:1:3

Unlike my esteemed colleagues, I believe ratios do matter. However:
(1) I know many ratios but what is meant to be 3:1:3??
(2) Ratios make sense only if you consider ALL nutrients, i.e. those which come with your tap (?) water and those you dose additionally. Their sum is what matters.
Nutrient deficiencies cannot be rationally solved unless we know what your water is like - at least pH and alkalinity (bicarbonate content). And when it comes to micronutrients, namely iron, there's no recommended concentration to maintain. Iron deficiency has to be detected visually.

 

[blairgerman]

Unlike my esteemed colleagues, I believe ratios do matter. However:
(1) I know many ratios but what is meant to be 3:1:3??
(2) Ratios make sense only if you consider ALL nutrients, i.e. those which come with your tap (?) water and those you dose additionally. Their sum is what matters.
Nutrient deficiencies cannot be rationally solved unless we know what your water is like - at least pH and alkalinity (bicarbonate content). And when it comes to micronutrients, namely iron, there's no recommended concentration to maintain. Iron deficiency has to be detected visually.

The NPK ratio appeared to be modal, or at least salient, from my review of forum literature on the topic, though I see a lot of variance, regarles, i figured that'd be a good place to start. The actual dosages of NPK i derived from the barrreport calculator I was using for EI (before I found @Hanuman 's) Targets were ~7.5 NO3 (from KNO3), ~1.3 PO4 (from KH@PO4), and ~7.5 of K (from K2SO4). I also based my CSM+B from this calculator for .2 target, but i had titrated that to somewhere around .9.

However, since I started using @Hanuman 's calc i reversed my dosages and it output these numbers in the bottom right which appear to be inappropriate for the EI dosing comparator.

Current tank parameters are: Gh 7, Kh 5, N 25, Phos 5, TDS 275. Tap is currently N 10, Kh 2, Gh 9, Ph 7-7.5, TDS 155.

I wc 36gal premix (50%) and add add a heaping spoon of bicarbonate to get kh to 5-6 range. I *used to add Gh Booster (22%K2O, 10%Ca, 1.5%Mg, 17%S) but 7 months ago I moved to tampa bay area where I had 13gh and 350 tds tap water, so I discontinued adding Gh booster. Per my testing of the tap water, and this water report, and reports from locals, I was told calcium was high due to lots of limestone and cocina, and the CaCO3 values here

*HOWEVER, 2 months ago the utility company arrived and stated the main feed line to my building was severely rusted and leaking. They did a massive dig and reaplced lots of pipe - since then the gh and tds is way down and I fid not resume the gh booster.

As for micro's, from my journal, Daily micros AM: DTPA Fe .325, MnSO4 .075, ZnSO4 .040, Boric Acid .035, CuSO4 .003, Ammonium Molybdate .002

@_Maq_ , please forgive the messy way i've reported this data here and I'm grateful for any type of feedback on this!

 

[_Maq_]

add a heaping spoon of bicarbonate to get kh to 5-6 range.

Bicarbonates are of no good. They increase pH, and hinder uptake of iron. I presume you mean sodium bicarbonate, which is even worse because of sodium which can hinder uptake of potassium, calcium, and magnesium. Sodium is not an essential nutrient.

it output these numbers in the bottom right which appear to be inappropriate for the EI dosing comparator.

I don't use @Hanuman 's calculator so the numbers are a bit difficult to decipher for me. Never mind. Do I gather correctly that 3:1:3 ratio is meant for K:Mg:Ca? Then I would recommend rather different one: 1:3:10. Lower content of Ca is often acceptable, but there should be always remarkably more Mg and Ca than K.
I know I know I know... Tom Barr and many others think and do differently. Yet I've tried their ratios (and amounts) and it worked poorly for me. Perhaps that's because I'm running low-tech, so my plants do not have that plenty of energy to handle incorrect ratios.

 

[blairgerman]

Bicarbonates are of no good. They increase pH, and hinder uptake of iron. I presume you mean sodium bicarbonate, which is even worse because of sodium which can hinder uptake of potassium, calcium, and magnesium. Sodium is not an essential nutrient.

I don't use @Hanuman 's calculator so the numbers are a bit difficult to decipher for me. Never mind. Do I gather correctly that 3:1:3 ratio is meant for K:Mg:Ca? Then I would recommend rather different one: 1:3:10. Lower content of Ca is often acceptable, but there should be always remarkably more Mg and Ca than K.
I know I know I know... Tom Barr and many others think and do differently. Yet I've tried their ratios (and amounts) and it worked poorly for me. Perhaps that's because I'm running low-tech, so my plants do not have that plenty of energy to handle incorrect ratios.

Aye, I'm sorry the 3:1:3 ratio was for NPK and I had :1 for Mg (from KNO3, KH2PO4, K2SO4, and MgSO4) Calcium I had not added after discontinuing the Gh Booster which was my source. I was totally uneducated on a K:Mg:Ca ratio.

What product should I be seeking for a baking soda replacement for the alkalinity? And a source for Ca...? Is the CaCO3 content in my water report a useful source to consider? I think I used to get my Ca from the gh booster i used to add to my wc prep (22%K2O, 10%Ca, 1.5%Mg, 17%S).

 

[MichaelJ]

I wc 36gal premix (50%) and add add a heaping spoon of bicarbonate to get kh to 5-6 range.

What @_Maq_ said. There is absolutely no reason to raise your KH for the sake of your plants - and it might even be detrimental as you are hampering uptake. The only reason I can think of to raise KH and thus pH buffering capacity, would be for the sake of livestock, if you are keeping species that do not go well in acidic water and need to be kept in a certain higher pH range - in which case you should compromise in favor of your livestock.

there should be always remarkably more Mg and Ca than K.

This is growing on me

Cheers,
Michael

 

[X3NiTH]

a heaping spoon of bicarbonate to get kh to 5-6 range

I would omit adding MgSO4 (already a decent amount of Sulphate in your tap water) and swap to MgCO3 at waterchange for both the Magnesium and the Carbonate. Use in conjunction with KH2CO3 to boost your Potassium level and Carbonate.

Nothing wrong in having a little extra carbonates in the water as long as it’s consistent.

 

[blairgerman]

The only reason I can think of to raise KH and thus pH buffering capacity, would be for the sake of livestock, if you are keeping species that do not go well in acidic water and need to be kept in a certain higher pH range

yes it for buffering... to avoid needing a swing from 7.5 to 6.2 to get 30ppm CO2, I have mainly tetra, rasbora, and neocardinia in this tank which could probably do 6.2 but the swing might be a lot for them. Any other options for buffering than baking soda?

 

[blairgerman]

I would omit adding MgSO4 (already a decent amount of Sulphate in your tap water) and swap to MgCO3 at waterchange for both the Magnesium and the Carbonate. Use in conjunction with KH2CO3 to boost your Potassium level and Carbonate.

Nothing wrong in having a little extra carbonates in the water as long as it’s consistent.

Perfect! Okay, I would begin sourcing these: MgCO3 and KH2CO3 asap! hopefully before my wc comming tuesday Thank so much guys!

 

[blairgerman]

I would omit adding MgSO4 (already a decent amount of Sulphate in your tap water) and swap to MgCO3 at waterchange for both the Magnesium and the Carbonate. Use in conjunction with KH2CO3 to boost your Potassium level and Carbonate.

Nothing wrong in having a little extra carbonates in the water as long as it’s consistent.

So for my wc premix I will be adding magnesium carbonate, yes? ... and I assume I would calculate this amount based on a weekly target for a single dose per week of MgCO3? And the potassium bicarbonate would go in my daily macros mix? (to replace the K2SO4) Do I need to be adding a source of Calcium?

 

[X3NiTH]

Yes and yes. Treat the potassium bicarbonate the same way as the magnesium carbonate dose at waterchange (we want consistency in KH and not rising through the week) this K dose should be sufficient for the plants week to week through waterchanges. You shouldn’t need to add any extra Calcium according to your water report (if the underlying Limestone geology of the water source is ancient it will be mostly Ca and have little Mg in it), plant Ca:Mg ratio is 3:1 you’ll never need to exceed that ratio for Mg in the water.

 

[X3NiTH]

Okay checked you’re in Florida, it’s ancient Karst Limestone formations so there should be some Mg along with Ca in the water.

 

[Hanuman]

For this Tank Journal

I run a wet/dry sump, doser, anoxic reactor, co2 reactor, 2x165w black box lights, co2 controller.
Plants: Cuba, M.Carlo, Nana pettite, xmas moss, D.Sag, Red Lud, 2 others unidentified - LMK pls
Substrate: Inert, eco complete
Routine: Co2 at 30-40ppm (kh 5.5, ph 6.6 - one point swing from 7.5)
Weekly 50% wc (Very hard tap water - 13gh with has lots of calcium, i do not remineralize)

*HOWEVER, 2 months ago the utility company arrived and stated the main feed line to my building was severely rusted and leaking. They did a massive dig and reaplced lots of pipe - since then the gh and tds is way down and I fid not resume the gh booster.

Multiple comments to start with:

• You are pumping 330W of light in that tank which is a lot.
• You have a sump which usually means more off gazing of CO2 than with other systems (canister, HOB etc). It's not a bad thing but it could mean that you have less CO2 in the water than what you think you have.
• Although not that high you still have some good KH in there which could be part of the issues you are seing.
• TAP water parameters seasonal variations and due to upgrades to the water system could also be in play here.

but the holes do indicate K deficiency and @Hanuman's calculator indicates my K is 1/3d where it should be (assuming I'm using the calc right).

Not necessarily no. Could be CO2 or a combination of multiple deficiencies + KH.

Current tank parameters are: Gh 7, Kh 5, N 25, Phos 5, TDS 275. Tap is currently N 10, Kh 2, Gh 9, Ph 7-7.5, TDS 155.

This means something in the tank is releasing carbonates since it's not 100% coming from the TAP water.

All in all, You have many variables that could be responsible for what you are seeing but my gut feeling tells me that your issue is related to very high light combined with not enough CO2 (in relation to the light you are pumping). The whole thing with higher carbonates in the water hindering nutrient uptake. Most if not all the plants you have in that tank are easy plants with low requirements. You also need to keep in mind that when plants grow, their uptake also grows, so you also need to be adjusting CO2 and ferts once in a while.

As for ratios, although they have their rational and scientific truth, are in my opinion simple guidelines that one can follow but should not be a strict law unless you want to run some experiment. We are growing plants for pleasure, not to make our life a leaving hell with numbers and lab precision weights/ratios. If you look in the IFC calculator all the products have slightly different ratios, some of which can differ to some extent. They will all grow plants fine. This tells you something about ratios. They are probably of more significance for terrestrial plant growing IMO. I am not saying these ratios are BS just that you should not be worrying too much about it. Rather, look are more simple factors like CO2, light, and your KH.

Finally, don't be changing multiple parameters at once else you will never know what your issues was.

 

[blairgerman]

@Hanuman
Thank you so much for chiming in on this, the way I presented my data is hard to digest. The only factor I changed after a good period of consistent adequate growth was switching my micros, which caused the significant deficiencies in the ludwigia shown in the pictures above. If i can get my micros sorted to return to producing the growth I had previously, then that is my first goal and I plan to wait to change any other fert or remineralization procedures discussed in this thread till I finish sorting this one independent variable (many actually since i went from CSM+B to DIY micros with DPTA and gluc Fe)

For the co2 off-gassing, absolutely! I run what I guess is 20+ bps, the drip tray probably off-gasses most of it. However, I wonder what you think about the fact I have my ph probe in the sump, after the drip tray, just before the return pump. My assumption has been that, given a known kh, once the ph target is reached and the ph controller turns off the solenoid, one could assume the co2 concentration is basically what the ph/kk/co2 relationship indicates? I have the controller set for a 6.5ph target for photo period, at night ph is at 7.5, so i figured the 1 point drop is representing a significant amount of co2 being added then maintained as the controller turns the solenoid off and on to maintain the 6.5ph.

Regarding Kh, I think it's higher in the tank than at tap cuz i add baking soda at wc, right? I do plan to discontinue this practice, but only after sorting this one variable I'm changed (the micros).

Yes it's a LOT of light, I have 2 years on this tank adjusting variables before I got algae free... I just really need to learn more about observing healthy plant growth from you guys.

Regardless, I have about ~30 hours using your calculator these past few weeks, so just thanks so much for that.