Lowering KH with acid stuff

[Petex]

hi,
I want to lower my KH (i know must ppl buy a Osmose thing)
I also know some ppl. lower KH by using HCI, but doing so will add Chlorid
A few use H2SO4, but this will add Sulfates.
Having much Chlorid or sulfates didn´t sound like good thing for me.
OK, very few use HNO3, but it adds 22mg/L for each lowered -1KH
All those acid are also dangerous to handle.

So I came up to the conclusion to give H3PO4 a try.
Doing so will certainly add much PO4 and my idea is now simply to remove this with Phoslock/EisenIIIhydroxide (FeO3)

Did anything speak against this idea?

If nothing speaks against it:
how much ml H3PO4 in a 10l box is requierd to lower KH for each (-1) step?
How much % should that H3PO4 acid have?

thx. peter

 

[Tom Barr]

Vinegar works fine and is much cheaper.

 

[Petex]

Vinegar is an organic acid, so what will be left in the tank after dosing it ??
Will organic acid obvisously make "bacteria big bloom"?

Can you tell me exact dosing for H3PO4?

 

[Biollante]

Not Sure I Understand

Hi,

1. Vinegar is an organic acid, so what will be left in the tank after dosing it ?? (sic)
   1. Vinegar is water, acetic acid, so assuming acetic acid is the limiting reactant, water and CO[SUB]2[/SUB] are the product.
2. Will organic acid obvisously make "bacteria big bloom"?(sic)
   1. No, I see no reason it should; I have never seen that happen, if you want a bacterial bloom use sugar.:surprise:
3. Can you tell me exact dosing for H3PO4? (sic)
   1. Not enough information, what am I dosing, what is the purpose, what is the molarity?

Biollante

 

[Tom Barr]

Vinegar is an organic acid, so what will be left in the tank after dosing it ??
Will organic acid obvisously make "bacteria big bloom"?

Can you tell me exact dosing for H3PO4?

Phosphoric acid like pH down is typically 30%.

But I'm not sure what the concentration of what you have is...........

Do not add a strong acid to water with fish in it FYI..............you will kill them.

Like vinegar, you will pickle them and strong acids like HCL etc....you end up burning the gills.

 

[Petex]

My tap water is KH 2-3 and I want to make it KH 0 (only for filling up condensated water)
Tank size is 11Liter and water condensation is around 2Liter a week.
I refilled all the time the condensated water always with tap water - but doing so is not any good thing and meanwhile my KH is 6. Some plants dont like this.
So I want to add KH0 water in future for filling up any condensated Liter.
Certainly I will mix the stuff outside the tank.
I know that any acid will produce much Co2 and that it also must be gas out (with air stone)

No, I see no reason it should; I have never seen that happen, if you want a bacterial bloom use sugar.

Can vingage from food/super market be used or did it contain "some other stuff"?
Is buying "clean vingage acid" only from drugstore/apothecary recommend?

Phosphoric acid like pH down is typically 30%.
But I'm not sure what the concentration of what you have is...........

I have 25% phosphoric acid here.
How much should I add for each 10L to lower KH2 to KH0?
And how much Po4 will it produce?

 

[Tom Barr]

A fair amount of PO4 will be added to the water.
Distilled white vinegar might be the easiest option.
Most grocery stores will have this, food grade is good enough for you and good enough for the water.

I would just make sure to allow the water to sit a day or so before adding to the tank.

 

[Petex]

Hi,
Well, I now simply maked a 12% phosphoric acid test solution and figured out the following:
1L water (with KH2) and adding 0,2ml = KH 1,5
adding 0.3ml = KH 0.75
adding 0.35mk = kH 0.5
adding 0.4ml = KH 0 or 0.25 (I don´t know exactly, what the drop test tells me in this case)

OK, certainly there is much Po4 now and I buyed Sera Phosvec (because the petshop guy told me it is Feß3) --> but after I opened the box it is any white looking granulate:
http://www.aquarent.info/product_info.php/products_id/259
This did not look like all the other FeO3 Phosphate Remover stuff.
What it this sera for a stuff and how long will it take to remove all Po4?

Distilled white vinegar might be the easiest option.
Most grocery stores will have this, food grade is good enough for you and good enough for the water.

I will try this after my tests with the phosporic acid.

 

[Tom Barr]

Acetic acid only leaves CO2 and water.............

PO4 is good for plants, so this might help them grow better.

 

[Petex]

Certainly PO4 is necessary and PO4 Levels around 1-5mg/L may be "ok".
I currentöy still don´t know exactly how much it really adds. Sources from the internet claim it adds 22mg/L by lowering KH -2.
But I get other results and my Po4 test kit tells me anything around ~5-8mg/L.
Need to check out this issue tomorrow closer.

 

[Tom Barr]

I think we could ask "Wet" to add that and few others to the dosing calculator, there is a German version also.

 

[Biollante]

Dicalcium Phosphate Anyone?

Hi Peter,

Sorry for my confusion on what you were asking.

My suspicion is the internet sources that say you should have [SUP]22mg PO[/SUP][SUP]₄[/SUP]∕[SUB]l[/SUB] are referring to the total phosphate,

• presuming a molar equal reaction H[SUB]3[/SUB]PO[SUB]4[/SUB] + CaCO[SUB]3[/SUB] → CaHPO[SUB]4(s)[/SUB] + H[SUB]2[/SUB]O + CO[SUB]2(g)[/SUB]
  
• that would leave the phosphate in the form of Dicalcium phosphate,
  
• which is not readily soluble, something like [SUP]2g CaHPO₄[/SUP]∕[SUB]l[/SUB].
  

Your test for phosphate is only going to reveal aqueous phosphate, not the phosphate bound with the Calcium.

Biollante

 

[Petex]

If it would bound to Calciumphosphat, obvisously it will bound Magnesiumphosphate, too?
I thought the carbonate will be simply gas out as Co2?

Vinegar is water, acetic acid, so assuming acetic acid is the limiting reactant, water and CO2 are the product

I tried vinegar, too.
I have a small Test tank (without animals) for such experiments and apply it directly into the tank.
KH4 goes down Kh1.

So far, so good, but can direct apply damage plants?

I think we could ask "Wet" to add that and few others to the dosing calculator, there is a German version also.

What means "wet", where did I find the calculator?


Hey, sry for my worst english

 

[Florin Ilia]

What means "wet", where did I find the calculator?

Wet is a user on this forum; he's active on other forums as well: http://www.barrreport.com/member.php/9-Wet

He is the author of this website: http://petalphile.com

which includes a famous calculator: http://calc.petalphile.com

 

[Biollante]

Distilled White Vinegar

Hi Peter,

Yes, the carbonate, CO[SUB]3[/SUB] ends up as CO[SUB]2[/SUB] and H[SUB]2[/SUB]O, the CO[SUB]2[/SUB] is a gas at that point and like any other CO[SUB]2(g)[/SUB] entering the water column may dissolve, simply bubble off, or some combination.

You are also correct regarding the phosphate, binding with either Calcium or Magnesium, Magnesium phosphate being even less soluble about [SUP]2.5mg Mg[/SUP][SUP]₃(PO[/SUP][SUP]₄)₂[/SUP]∕[SUB]l[/SUB].

I am once again confused as to what you are trying to accomplish and why it matters so much which element in the water binds the phosphate.

I was trying to answer your question from post#10. Since we measure carbonate hardness, in equivalent units of CaCO[SUB]3[/SUB], we do not know that it is CaCO[SUB]3[/SUB], in the water column; we only know that for each dKH measured there is about [SUP]10.26mg CO[/SUP][SUP]₃[/SUP]∕[SUB]l[/SUB] so if you have 4-dKH we know you have about [SUP]41mg CO₃[/SUP]∕[SUB]l[/SUB] to do with as you please.

Another way to look at this, if you started with 1-liter of perfectly distilled water and wanted 4-dKH you could:

• Add 68-mg of crushed eggshell (CaCO[SUB]3[/SUB]) (dissolving it might be time consuming) that would also add 4-dGH.
• Add 58-mg of baking soda NaHCO[SUB]3[/SUB], dissolves easily, adds no GH and provides [SUP]16mg Na[/SUP]∕[SUB]l[/SUB] to provide desperately needed electrolytes.

In our baking soda, hypothetical we still have the same amount of carbonate to be disposed of the difference is if we use Phosphoric acid that we end up with Na₃PO[SUB]₄[/SUB], which unlike other phosphates is soluble, about [SUP]121g Na₃PO₄[/SUP]∕[SUB]l[/SUB].

Using distilled white vinegar would solve most of your concerns, which apparently I do not understand.

Personally I do not think driving carbonate hardness below 2-dKH is ever a good idea, then there is a lot of foolishness on the internet.:chargrined:

Biollante

 

[Petex]

Using distilled white vinegar would solve most of your concerns, which apparently I do not understand.

Tap water has Kh2.
The KH in the Tank increased to KH6 and I want the tank back to KH3.
# If I make 50% water change with KH2 water, the tank will end up in KH5 or so.
# If I make 50% water change with KH0 water, the tank will end up in KH3
I am right?
So, my idea was to destroy KH from my tap water that I would use for a 50% water change to get KH6 in my tank down to 3.

Another way to look at this, if you started with 1-liter of perfectly distilled water and wanted 4-dKH you could:

So did this mean KH should better only be reduced with destilled water?

 

[Florin Ilia]

Everyone step aside, expert speaking

(50%)KH6 + (50%)KH2 = KH4 (not KH5)
(50%)KH4 + (50%)KH2 = KH3
So you can accomplish KH3 with 2 x 50% changes with your tap water. If you take some time between the changes it may even be better than to soften it immediately.

Or, in one shot:
(25%)KH6 + (75%)KH2 = KH3

In any case, you don't need to destroy anything.

 

[Petex]

hi,
thx. for the correction, yes 50%KH6+50%KH2 should be KH4 and not KH5.
But you may consider that KH will soon again increase as so long I always add KH2 water for any condensated liter.

 

[Petex]

Will organic acid obvisously make "bacteria big bloom"?(sic)
1. No, I see no reason it should; I have never seen that happen, if you want a bacterial bloom use sugar.

OK, I tried it because you and Tom recommend it and my conclusion is the following:
# vingage "seems" to work "fine" in "old" and "well cycled" tanks
# vingage "seems" not to work any good in new tanks

Attached are images from a new started tank.
Day 1 (NPK+trace dosing)
Day 2 (NPK+trace dosing)
Day 3 (NPK+trace dosing)
Day 4 (NPK+trace dosing)
Day 5 (NPK+trace dosing)
+ adding 6ml vingage solution (thats not much and lowers KH only -1!)
Day 6 (NPK+trace dosing)
Day 7 (NPK+trace dosing + Magnesiumsulfat-Hept)
= next day, the whole tank looks pretty "white milky & cloudy"

Having such a bloom didn´t look like a good thing for me. (you may consider this is only a Nano tank and if you would have such a bloom in any large tank = you would for sure not see the other end off the tank)
Magnesiumsulfat normally don´t make tanks any cloudy, so it must have something to do with the vingage stuff.
Perhaps it only happens on new tank setups -or- perhaps vingage shouldn´t be used together with some other or sulfat stuff.
And as so long such things "are unsure", I wouldn´t recommend it for any new tank setups.
(Such things do not happen with Phosphoric acid)

 

[Tom Barr]

Bacteria will consume the left over compounds from acetic acid in a mature tank. In a new tank, the bacterial population is not stable yet, so yes, with that said, organic acids might be the best solution.

The cloudiness is due to the by products of acetic acid/vinegar in a new aquarium.
This sometimes happens in reef tanks where they add sugar, vinegar, or vodka dosing etc.......to reduce carbon limitation for bacteria that need more reduced carbon to remove NO3=> N2 gas denitrification.

If you have H3PO4, might as well use it also for the new tank.

Or switch out the new filter and the old filter between tanks/or switch the media to seed the new aquarium.
After 1-3 weeks, the new tank should be well cycled.