EI and Remineralising RO

[Sacha]

This has been bugging me for a while now and I finally want to sort it out once and for all... I could really do with the help of someone more chemically- minded than myself.

I change 50% of my tank water each week. I use pure RO (zero TDS), and remineralise it with JBL Aquadur.

I add enough Aquadur to bring the KH to about 3, and the TDS to around 120-150 PPM. I also add a 1.5x of EI daily.

According to this PDF:

https://www.jbl.de/faqfiles/393/AquaDur_Web_V01_GB.pdf

JBL Aquadur is made up of:

Cations:

45% Calcium
32% Sodium
13% Potassium
10% Magnesium

Anions:

45% Hydrogen Carbonate
32% Sulfate
23% Chloride

I have a few concerns here. First of all, the sodium content is quite high. Am I right in thinking my plants will not appreciate that?

Secondly, the remin contains a decent amount of potassium and magnesium. Obviously I dose both of these in my Macro EI mix. Is it pointless for me to dose the Macro EI as well as these remin salts?

Ideally, I would want to be able to add more KH, while adding less TDS. What I mean by this is I would like to add a decent amount of carbonate/ bicarbonate, while adding a decent amount of potassium, calcium, magnesium etc, but while adding a MINIMAL amount of sodium, and a minimal amount of chloride.

Am I right in thinking that it is possible to use Potassium Bicarbonate instead of Sodium Bicarbonate in order to increase KH? Would it be worth me adding some Potassium Bicarbonate into my JBL Aquadur, so that I could add more KH with less PPM of Aquadur?

I hope this all makes sense. I basically want to optimise my Re- min and ferts regime, to make sure I am adding the right amounts of the good stuff, and as little as possible of the bad stuff.

Any help is greatly appreciated.

 

[Sacha]

Thought I'd add,

The TDS of the water going in is about 150. By the end of the week, the TDS in the tank is about 350. So that's a lot of PPM being added through ferts. I am adding magnesium and potassium twice, so I should alter what I'm doing in some way surely.

 

[dw1305]

Hi all,

First of all, the sodium content is quite high. Am I right in thinking my plants will not appreciate that?

They won't, you don't need to re-mineralize RO if you are adding EI fertilisers.

Am I right in thinking that it is possible to use Potassium Bicarbonate instead of Sodium Bicarbonate in order to increase KH?

Yes.

Would it be worth me adding some Potassium Bicarbonate into my JBL Aquadur, so that I could add more KH with less PPM of Aquadur?

Just don't add the re-mineralising salts at all.

I basically want to optimise my Re- min and ferts regime, to make sure I am adding the right amounts of the good stuff, and as little as possible of the bad stuff.

Just add the EI salts and if you want to raise dKH use KHCO3 and the calculator at "James' Planted Tank" <http://www.theplantedtank.co.uk/RO.htm>.

cheers Darrel

 

[Sacha]

'You don't need to re- mineralise RO if you are adding EI fertilisers'

I have heard that on this forum several times now, and I still don't understand how it can possibly be correct.

Above all, The fish and inverts need calcium. That's not in the EI ferts. If you added non- remineralised RO to a shrimp/ snail tank, their shells would simply dissolve.

They need carbonates. Also not in the ferts.

They need magnesium in larger quantities than are in the ferts...

 

[dw1305]

Hi all,

I have heard that on this forum several times now, and I still don't understand how it can possibly be correct.

You don't need to buy a re-mineralising mix. You've already pointed out the one you use is 33% NaCl.

If your mix doesn't include any calcium you can add some. If you have hard tap water you can cut your RO with 25% tap etc.

Above all, The fish and inverts need calcium.

They get most of this from their diet, a lot of S. American soft fish come from water that is pretty well devoid of any bases. Shrimps have an exoskeleton made of chitin, so they aren't like mollusks or corals, and even some snails can live in acidic calcium poor water if they have access to enough calcium from their food.

They need carbonates. Also not in the ferts.

Only in small amounts, you can always add some "oyster shell chick grit" to the water if you are really concerned.

They need magnesium in larger quantities than are in the ferts...

Again if you are worried add some "Epsom Salts" (MgSO4.7H2O).

All the details are in the linked thread at the excellent "James's Planted Tank".

cheers Darrel

 

[Sacha]

Thanks a lot for your help Darrel. I need to read through this all carefully and work out what to do.

 

[Sacha]

Just out of interest, what is the problem with sodium in a planted tank?

 

[ian_m]

Just out of interest, what is the problem with sodium in a planted tank?

http://www.skepticalaquarist.com/water-softening

 

[dw1305]

Hi all,

http://www.skepticalaquarist.com/water-softening

Great link, I love the Skeptical Aquarist, great information and very well written.

cheers Darrel

 

[Sacha]

Pretty much the same I have seen everywhere else:

'Sodium is a bad thing in aquariums'

What's the science behind this claim? What chemical processes are at work that impinge on the fishes' and the plants' wellbeing?

 

[dw1305]

Hi all,

What's the science behind this claim? What chemical processes are at work that impinge on the fishes' and the plants' wellbeing?

Have a look at this one for fish and water issues. "Water Chemistry: Osmoregulation, Ionic Imbalance & pH" <http://www.tbas1.com/Exchange/The New England 11.pdf>.

Plants are slightly different, for most plants sodium (Na) is irrelevant, they don't need it, but they still take up small amounts. This is also why the sea is salty with Na (and chlorine Cl), they aren't the most common elements in the lithosphere, but they aren't needed in large amounts by plants, and over time their levels have built up in the sea.

This is from: <http://www.sebiology.org/publications/Bulletin/July05/salinity.html>

Because Na has such adverse effects on many plants ........ is studying why crop plants don't seem to have an 'off switch' where salt is concerned, and can accidentally accumulate it until it kills them. “Most plant species show no nutritional requirement for Na+, although addition of Na+ can enhance growth in some conditions” she says. “So it is surprising that two genes, apparently for Na+ specific transporters, have been identified in the salt-sensitive model plant Arabidopsisthaliana”. Transporters are proteins within the cell membrane that allow ions (such as Na+) or other small compounds to travel into the cell and between cellular compartments. “The Na+ transporters also affect potassium (K+) balance and root development, suggesting that Na+ transport may have important physiological functions under nonsaline conditions”

cheers Darrel

 

[Edvet]

Sodium is important in land based cell's though

 

[David Shanahan]

I think this is why I had problems when I attempted scaping a tank. I was remineralising and adding EI and was wondering why my plants kept failing or having issues with algae. I'm about to get back into it. I've been wanting to get a tank up and running for ages!

 

[Manuel Arias]

Interesting discussion here. Please allow me some comments:

1. I agree with Darrel that you do not need to add at all any source of NaCl. A re-mineralizer getting that is just thought to be cheaper (i.e. more weight for the same GH capability). Note that NaCl will not increase, at all, your GH, which is related mainly to Ca and Mg. If you wnat to use something commercial, employ Seachem Equilibrium. If you want to use DIY salts, then use the normal GH booster: 3:1 of CaSO4.2H2O and MgSO4.7H2O. If you want to mimic the Seachem, then add also K2SO4 in same amounts than CaSO4.2H2O and perhaps some FeSO4. That's all.

2. Both Ca and Mg are required by inverts and fishes. Impact, however, is different. For inverts, the availability of these ions must be done accordingly with the right amount of (bi)carbonates in water and pH balance. Otherwise they will struggle to generate and preserve their shells. This is called Omega-point of carbonates saturation: http://www.whoi.edu/OCB-OA/page.do?pid=112076. In case of fishes, Ca is a critical element used in osmoregulation and also in neuronal transmission. More specifically, Ca is critical for the work of mussle tissue. Without it, contraction of cells is not possible. They will, however, take it from diet, as Darrel said, but some amount in water also helps them to keep the levels. That something is not intrinsically needed, it does not mean at all that having it will not help.

3. Good website that one of skepticalaquarist. However, I manage only to access the main page. Rest of links report Error 404, so site is offline (at least for me).

4. As pointed out by Darrel, Na plays a role in the osmorregulation of living things. The problem is more important in the ocean than in freshwater. Na+ ions are very small so they pervade the membranes of cells. Oceans have lot of Na which means that Na is in much higher concentration in water than in the bodies of the organisms. As a result, Na has a natural tendency to permeate inside the cells, what alters the electrostatic balance of the membranes and also the osmosis processes. If perturbation reaches certain levels, the cells start to die. Because of that, marine organisms have many different strategies to control Na levels. For instance: Spending energy to actively pump out Na+ as exchange of taking H+; accumulating urea in blood and cells to increase the osmotic pressure and then reduce the inflow of Na (this is what sharks do, for example). In freshwater the problem is the opposite: Low concentrations in water means that the ion tends to leave the cells. Additionally, if preserved, it increases the entrance of water in cells, which can cause a turgidity problem (basically, blowing up the cell walls by excess of internal pressure). Freshwater organisms, however, have also mechanism to reduce this problem, like reducing their internal osmotic pressure to avoid the issue. The dropsy observed in fishes is nothing else that a disease caused by the interference of certain bacterial toxins in this mechanism, what makes the fish to accumulate water inside, and eventually, killing it.

This is also why the sea is salty with Na (and chlorine Cl), they aren't the most common elements in the lithosphere, but they aren't needed in large amounts by plants, and over time their levels have built up in the sea.

Sorry Darrel, but as oceanographer I can tell you that this is totally false: Sodium is one of the most abundant elements in lithosphere. In fact, it is a common element in clays, felspar and igneous minerals present in volcanic rocks like basalt. Sodium is the sixth more abundant element in the lithosphere, and chlorine is the twenty-first: https://en.wikipedia.org/wiki/Abundance_of_elements_in_Earth's_crust

Besides that, origin of both elements in sea water is much less related to continental washing than to ion exchange with volcanic rocks at the mid-ocean ridge, mainly associated to hydro thermal processes happening in the faults generated by crustal displacement forced by the mantle plumes, which are connected to higher temperatures in lithosphere. Table 2 of this paper shows the relative inputs from both sources, rivers and mid-ocean ridges: https://www.geochemsoc.org/files/2914/1261/1780/SP-2_409-420_Spencer.pdf: Import of Na from rivers is about 4500 times less important than mid-ocean ridge contribution, and for Cl the ratio is about 10800 times less. Potassium, Calcium and Magnesium also come from that source, mainly, and only point in which rivers are main contributors are carbonates. Never trust biologists when they talk about something else than biology (sorry for the bump here, but I observe at daily basis how biologist call themselves oceanographers when they are not).

Cheers,
Manuel

 

[dw1305]

Hi all,

Sorry Darrel, but as oceanographer I can tell you that this is totally false: Sodium is one of the most abundant elements in lithosphere. In fact, it is a common element in clays, felspar and igneous minerals present in volcanic rocks like basalt. Sodium is the sixth more abundant element in the lithosphere, and chlorine is the twenty-first:

I'd always assumed that was why the ocean is salty mainly with NaCl?

I've just had a look at potassium which is the 7th most common elements in the lithosphere and essential for plant growth.

and then compared the abundance, and residence time, in sea-water of sodium (Na) and potassium (K).

Sodium abundance in Earth's crust ~28,300ppm
Potassium abundance in Earth's crust ~ 26,000 ppm

Sodium abundance in seawater ~ 11,000ppm
Potassium abundance in seawater ~ 390 ppm

Sodium residence time ~ 72,000,000 years
Potassium residence ~ 16,000,00 years.

cheers Darrel

 

[Manuel Arias]

Plants are slightly different, for most plants sodium (Na) is irrelevant, they don't need it, but they still take up small amounts. This is also why the sea is salty with Na (and chlorine Cl), they aren't the most common elements in the lithosphere, but they aren't needed in large amounts by plants, and over time their levels have built up in the sea.

I missed the first part of your sentence, in which you establish a causal relationship between plant requirements and Na Cl in sea water. Because of the plants do not use it, it is then wasted to oceans and accumulated. This is not true, and most of Na Cl come from the mid-ocean ridge ion exchanges, as I pointed out and clear in the paper. It is this mid-ocean ridge exchanges what makes NaCl the most common salt in sea water, as different elements are exchanged at different rates, shown in the table.

The residence times are also important, but again, it is not related to plants but to chemical reactions, mineral formation and geological cycles. Meanwhile potassium is often introduced by the ridges, it is also exchanged by protons and Na in many minerals, reason why residence time is minor and concentrations lower, despite of the similar proportion with Na.

It is worth to mention, in any case, that these processes are just starting to be understood. For many years it was considered that rivers were driven composition of the sea water and then scientist were not able to explain the differential composition in sea water respect to rivers. Since the bloom of the Marine Geology discipline, we have started to dig in the issue, and the contribution of the hydrothermal processes in the ridges have proven to be the main controller of sea water composition.

Cheers,
Manuel

 

[dw1305]

Hi all,

Because of the plants do not use it, it is then wasted to oceans and accumulated. This is not true, and most of Na Cl come from the mid-ocean ridge ion exchanges, as I pointed out and clear in the paper. It is this mid-ocean rdige exchanges what makes NaCl the most common salt in sea water, as different elements are exchanged at different rates, shown in the table.

The residence times are also important, but again, it is not related to plants but to chemical reactions, mineral formation and geological cycles. Meanwhile potassium is often introduced by the ridges, it is also exchanged by protons and Na in many minerals, reason why residence time is minor and concentrations lower, despite of the similar proportion with Na.

Thank you, no that makes perfect sense.

cheers Darrel