Backyard Aquaponics
A place to discuss aquaponics

But Sodium Chloride doesn't soften water either... or not in any sense I know of.. chemically or otherwise...


Don't know what resin is being referred to in the above quote... but it would appear to be some sort of RO type of filter.... as it refers to removal of Calcium & Magnesium ions... usually found in "hard water"....

So yes... an RO unit... charged with an appropriate "resin"... through ionic exchange... will "soften" water...

But the "brine, usually of sodium chloride or potassium chloride" ... is used to recharge the resin...

It doesn't "soften" the water at all...



Then, sorry... but the use of the term "soften"... when applied to the use of sodium, or potassium chloride... to recharge the ioninc filter in an RO unit/filter...

Is a complete misnomer...

We'll talk in circles if we discus semantics and Australian versus British versus American English. It's just what we call it. Unless I'm wrong, so if someone in the US can tell me where/how I'm using it wrong. I'm not totally comfortable with lots of terms we use because they're misleading, but it many languages, you can't always take the meanings using direct and literal translation.

Here in the US, hardware stores sell big packages of water "softener" which is NaCl or KCl.

Regardless of what you call it or how, at least here in the states, Potassium Chloride is sold in giant bags for water TREATMENT.

Maybe you also classify it in two different ways. We have "temporary" hardness (referring to carbonate compounds) and "permanent" hardness (typically referring to sulphates/chlorides). It's all very confusing even to us.

The water softener systems using NaCl or KCl are used for temporary hardness.

Again, that's just how the words are used here. I can't imagine though that such systems don't exist in Australia (by some other name) that do the same thing. Either way, KCl is a cheap and abundant source of potassium and research has shown it's safe for fertilizer use.

Hmm.. maybe you guys don't use this type of system over there? I personally have never cared to use these systems but they're kind of common over here. The only reason I know anything about them is because the fish I keep prefer soft water and people ask all the time if they can use the above mentioned systems.

<shrug>

I'm kind of curious now if it is used in Australia. If so, maybe it's just not common or it goes by a different name. It's so common in my area that they're in about every gas station sitting on pallets (not de-icing salts either - which this time of year are out as well).

I've found numerous sources about this in the past but I did a quick Google Search for you and provided you the quotes and links. I was aware of KCl in "softeners" and I wanted to use it as fertilizer for my plants. We also use it here in the Northern US as "pet and lawn" safe de-icers (along with the more expensive Calcium Chloride w/ Sodium Chloride being the cheapest).

Based on the below, I would say it's safe. Chloride also offsets nitrite poisoning (that's why people tell you to add NaCl, it's not the sodium it's the chloride). So as many people here seem to add a lot of NaCl to their systems, KCl has the benefit of doing the same thing AND providing potassium fertilizer to your plants. I'm not an expert though, so you can draw your own conclusions from the below links....

"Potassium chloride (KCl), known also as muriate of potash (MOP), is the
most widely used source of potassium for agricultural crops."
http://www.ipipotash.org/udocs/1.%20Tab ... uction.pdf

"Potassium chloride (KCl), also called muriate of potash, is the most commonly used potassium fertilizer. It is a relatively inexpensive nutrient, and deficiencies can often be corrected with moderate rates of application. As a result, correcting a potassium deficiency can result in excellent economic returns."
http://www1.agric.gov.ab.ca/$department ... l/agdex917

hehe... or should I say petrol station? Since technically, petroleum fuel isn't a 'gas'

What He said
Is M.O.P. fish safe ? If so, it would be a cheaper source of pottasium.
What rates would you use?
Cheers

geez that's technical, I just chuck a tablespoon ish amount into the ft, it foams a little but not for long

2 grams per 100L of KCl should yield 10.49 ppm Potassium. Your target potassium level really depends on the plants, but I would keep it around 10ppm if not sure.

As a way to compare,...
2.00g per 100L of KCl is about 10.5ppm Potassium
2.71g per 100L of KNO3 is about 10.5ppm Potassium and
2.34g per 100L of KSO4 is about 10.5ppm Potassium

So adjust appropriately if replacing your other Potassium sources with KCl. From what I've read here, the nitrates in aquaponics setups are high enough that you can do without KNO3. The numbers are also close enough that a 1:1 replacement isn't going to be a big concern.

2.71 KCl is 14.21 ppm Potassium. Feel free to check my numbers, use at your own risk.

Close... but no cigar...

I suspect the terms "temporary" hardness... and "permanent" hardness... are those used by.. and/or conveyed...by aquaria shops...

The preferred terms are "carbonate" hardness.. and "general" hardness...

Carbonate hardness is a measure of the buffering capacity of the water... associated with the carbonate content.. and usually calcium carbonate...

As this... through nitrification.. is eventually exhausted... (hence pH drops)... it could be said to be "temporary"...

General hardness... is the meausre of the positive metallic ions in water... (often called "hard" water)... usually Calcium, Magnesium and Iron... and are not generally depleted/exhausted... hence they could be called "permanent"...

However it is not correct to attribute "permanent", or more correctly "general" hardness... to the measure of sulphates and/or chlorides....

Think about it... it wouldn't make sense to try and soften.. reduce the hardness... of something measured by the content of chloride ions... by adding chloride ions...

Nor will adding chloride ions.... Sodium, or Potassium... have any effect on the "carbonate" buffering... or carbonate hardness... of your water...

Snake oil would probably be just as ineffective...

And yes... the chloride ion is effective is de-icing....



No dispute about that...

But be wary of over-use... it will raise your salinity if you were to use it too often...

And Potassium is generally only needed as a "boost" at flowering/seeding/fruiting stages of plant growth...

This is true. I'll leave understanding semantics to the linguists.

Btw, did you just Google that or did you know all along? Like I said, the effectiveness of such systems was not the point of my post. That's just what they're called. The -point- of my post was that KCl is readily available.

Is this something you know or something that you're hypothesizing? The fundamental chemistry of what they're doing is true. The effectiveness is not something I can speak to since I don't use one or care to.

My head is spinning after trying to figure out this post. Thanks for all the tips on adding potassium to aquaponic systems, but does any one have a way to add potassium to a system with high pH (8.1) and high salinity (2.9 ppt)?

My system has been buffering at 8.1 for a while now, and I am trying to lower the pH, at the same time my salinity is high because I was treating my fish for ich and fin rot. Now I need to add potassium as my plants seem to have potassium deficiency. Potassium BiCarbonate, Potassium Hydroxide, and Potassium Chloride are all out of the questions unfortunately?

Oh yeah, and I don't have access to commercial fertilizers such as Maxicrop and others.

Cheers

hi all

i made potassium carbonate by burning banana peels and put the ash in bottle with water ( PH IS 11) , will it help the plants to get it if i spray that liquid on the leaves.?

What about potassium sulfate? Those chloride ions build up - but plants need sulphur.

Are you sure you have a Potassium deficiency?... At 3 parts per thousand of salt many plants will start to show signs of Sodium toxicity, which can present very similar symptoms to Potassium deficiency, ie: Yellowing between the veins and along the leaf margins, as well as necrosis of the leaf margins.

Potassium Sulphate may be an option. I've been told that Sulphate based products should reduce pH, but I recently added Manganese Sulphate to my system and it did nothing to the pH. So Potassium Sulphate may be an option for adding Potassium in this situation where kij2's pH is high... if it actually is a Potassium deficiency.