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Discussion Starter · #1 ·
Recently, I increased water hardness in my tanks with growing guppies, plants, and molting shrimp. This is because the well water I use went from a GH of 10-17, when I last measured it back around 1991 and 2007, to a too-low GH of 3. The decrease was due to continuous rainfall last few years. I followed the basic ideas in my book (p. 87). Goal was to increase water hardness in my tanks by adding key nutrients Ca, Mg, and K in as easy a manner as possible. This recipe won't increase pH (no carbonate salts) and it avoids loading up tank with sulfates by using commercial products (all the Ca, K, Mg come as sulfate salts).

I prepared (or had on hand) two key stock solutions.

Calcium: One is a CaCl2 (calcium chloride) solution. Mine was a saturated solution in an ancient bottle from a lab giveaway that I have kept for 20 years (photo). All CaCl2 preparations-barring those kept in a lab dessicator or lab oven--usually come with attached water molecules, plus CaCl2 quickly forms a liquid. So you can't really measure out crystals or liquids of CaCl2 accurately and assume you have added so much of the actual Ca. Measuring the effect that a CaCl2 addition has on GH is the best and most accurate way to measure how much Ca you are adding.

I added 5 ml (about one teaspoon) of the CaCl2 liquid (from brown bottle in photograph) to my 20 gal (80 liter tank). Starting GH was 4 and the addition increased it to 8, so the addition increased the GH by 4. This result with a 1:16,000 dilution was very acceptable. Done!

Magnesium: MgSO4 was from Epsom salts I bought at drug store (photo). Crystals came with some added fragrances, but otherwise its mostly MgSO4. Like CaCl2, MgSO4 comes with attached water molecules and gradually absorbs water, so you have to measure its effect on GH.

To prepare stock solution, I added 2 Tablespoons (~36 grams) of the Epsom salts to 2 cups (~500 ml) of tapwater. I had no idea how much this would increase GH, so I tested it by adding 1 ml to a quart of tapwater (~1 liter or 1,000 ml). GH increased from 3 to 5, so I knew that a 1:1,000 dilution would increase GH by 2 solely due to Mg.

Potassium: I purchased KCl from grocery store as a "salt substitute." I added 2 teaspoons (~12 g) to the Mg stock solution I prepared earlier. Fortunately, it did not form a precipitate. Thus, I could add Mg and K at the same time from this Mg/K stock solution.

I decided that my tank would do fine with a:1:16,000 dilution of each of my two stock solutions (Ca and Mg/K) in the tank water. (The main thing was getting enough calcium into the water.) To get a 1:16,000 dilution, I add 5 ml (~1 tsp) of each stock solution to 20 gal (80 liter) of tank water. 80 liters divided by 5 ml = 16,000. For a 10 gal tank, I'll add 2.5 ml of each stock solution, the same 1:16,000 dilution. When I change water I'll just add some of each stock solution. It doesn't have to be that accurate and doubling or tripling the 1:16,000 dilution "dose" that I add should not cause any problems.

In my experience, adding shells (CaCO3) to increase GH hasn't helped that much or worked fast enough. For example, I added 1 tsp of oyster grit to a 1 gal shrimp bowl and a month later GH had not increased above the starting GH of 3. If you use shells, please actually measure the GH in tank water to make sure that they are working.
 

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Discussion Starter · #4 · (Edited)
Is it possible that your well is getting ground water infiltration? is the water even slightly turbid? Mine is 150 feet deep and the chemistry never changed, regardless of rainfall.
I'm sure there's surface water infiltration. Water gets turbid every once in awhile. When I moved onto my wooded 4 acres 33 years ago, there was an old dog house over the well head. I replaced it myself with a little structure using concrete blocks for the sides and fiberglass panels for the top. But I never added the recommended concrete platform covering the surrounding soil, because I just hate mixing concrete!

Had a good laugh about MgCl2 used for making Tofu.
 

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Discussion Starter · #14 ·
In other words, do soft water plants adapt to hard water easier than hard water plants adapt to soft water?
It's not a question of adaptation but getting nutrients plants need for the synthesis of their proteins, DNA, Ca channels, etc.

Hardwater nutrients (Ca,Mg, K, S, etc) are essential for life, plants and fish. Softwater plants come from softwater habitats because they have adapted to an environmental niche where they they can survive better than "hardwater" plants. It gives them a competitive edge. Softwater plants are more adept than hardwater plants in sifting these nutrients out of the water. When softwater plants are transported to hardwater, they are in heaven. Now they finally can get these vital nutrients in abundance. (See p. 117 in my book for my experiment on getting a much greater yield growing softwater plants in hardwater.)

The reverse--transferring hardwater plants to a softwater tank--is a disaster. Now these plants are in an environment that contains none of the vital nutrients (Ca, Mg, K, S, etc) that they need. Plus, hardwater plants don't have the ability of softwater plants to sift these nutrients efficiently out of the water.

Decades ago, I couldn't understand how Arizona Aquatic Gardens and Florida aquatic plant nurseries (working with superhard water) could grow aquarium plants to sell. I too bought into the myth that softwater plants need softwater. Now, I understand.
 

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Discussion Starter · #25 ·
Is it possible to figure out how much of each I use to create stock solution and how much stock solution I can use in 40 liter tank.
The recipe for preparing stock solutions is my first post on this thread. If you've got just one tank, you may not need a stock solution. Here's what I'd try if I just had one tank:

I calculated dosage for a 40 liter tank and came up with 1/4 tsp (1,500 g) of "wet" calcium chloride (CaCl2∙H2O). Since CaCl2∙H2O is only 28% pure calcium, you are adding 422 mg of pure Ca. 422 divided by 40 liters = 10 ppm Ca. That's close enough.

I would just add a ¼ tsp of KCl and a pinch of MgSO4 and call it a day. Calcium is the most important nutrient.

Be sure to mix up each ingredient separately in a little water before adding to the tank. You don't want your fish eating pellets of CaCl2!

Thanks for sending all the details. I looked at Melbourne, Australia water quality. Interesting. Parameters look similar to New York City water. Nice water but very soft.
 

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Discussion Starter · #27 ·
This product, which I did not know about until you wrote, looks like a good and easy way to increase water hardness. Based on the product reviews and my own bias towards chloride as a safer anion, I would go with it. If you get bad results, please let us know.

Thank you so much for bringing this to my attention!
 

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Discussion Starter · #30 ·
You have a point. It seems Replenish is not designed for planted tanks. Na isn't the problem, it just doesn't have enough K and Mg.

Looking at the product ingredients, it has 13% Ca, 1% Mg, 0.12% K, and 0.6% Na.

We know that 100 ppm NaCl (which is 40 ppm Na), inhibits plants. Let's say you add enough Replenish to get hard water with 13 ppm Ca. That means you'll have added only 0.6 ppm Na. That 0.6 ppm Na is not much compared to 40 ppm Na and should not inhibit plants

Replenish only contains 0.12% K. If you add 13 ppm Ca, you're only adding 0.12 ppm K. That's probably not enough and K is a major nutrient.

Same problem with Mg.

Anyway, I thought Replenish would be an easy softwater fix, but I was wrong. I'll go back to my own homemade recipe as being better than either Replenish or Equilibrium. My book has the recipe (p. 87).
 

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Discussion Starter · #31 · (Edited)
I don't know much of the science behind water hardness, could someone explain why sulphate salts would be more/less harmful than sodium and chloride?
Good question. A little sulfate is fine AND sulfur (S) is a major nutrient. However, too much sulfate in the water can cause problems in a tank containing an organic soil underlayer. Most potting soils and other organic soils become quite anaerobic when submerged. If there's a lot of sulfates in the water, they will percolate into the soil layer. Sulfate-reducing bacteria (my book, p. 67) will convert these sulfates into H2S (hydrogen sulfide). This smelly gas kills plant roots, inhibits plant growth, and may even harm bottom-dwelling fish. H2S is more toxic than ammonia.

Chloride is not toxic and presents no such problems. (This has been discussed thoroughly in another thread.)

If you look at the Equilibrium product, it is made solely from the sulfate salts of Ca, Mg, K, Fe, and Mn as in CaSO4, K2SO4, MgSO4, etc. That means when you add Equilibrium, you are adding a TON of sulfates. This product may work in gravel or sand tanks or ones with a mineral type soil, but not ones with an organic soil underlayer.
 

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Discussion Starter · #37 ·
I don't think that any of the minor ingredients listed for the 'Salt Substitute' would cause a problem.
 

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Discussion Starter · #42 ·
I planned on mixing together all the chemicals in a single jar, so next time the measurements would be easier. Never got around to it though, as I only needed to raise the hardness that first time.
If you mix the chemicals, you may get a white precipitate (solid particles) that is essentially useless or impossible to work with or measure or go into solution.

[I suspect that water-hardening commercial products are formulated for ease of use by hobbyists, and why SeaChem's 'Equilibrium' is all sulfate salts. The vendors have mixed Ca, Mg, K, etc salts that won't precipitate "on the shelf." I actually spoke with SeaChem's sales representatives (very nice people) decades ago about making an Equilibrium-like product with less sulfates, but nothing came of it.]

That said, I'm glad that you got what you wanted. Very good....
 

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Discussion Starter · #48 ·
Calcium chloride (CaCl2) is very soluble. It goes into solution immediately, plus it will not change pH. CaSO4 (Calcium sulfate) is probably soluble as well.

CaCO3 (calcium carbonate) the component of shells, coral, and limestone is the compound that is not very soluble. And it will raise pH.

Your recipe using only sulfate salts of Ca, Mg, and K is not a good idea. You are adding too much sulfate. Sulfates build up in the water and percolate into substrate. Anaerobic bacteria in the substrate will convert sultates to the highly toxic gas H2S (my book, p. 67). H2S will kill/inhibit root growth and bottom-dwelling fish. Sulfates can cause major problems in substrates containing potting soil underlayers or even gravel substrates with anaerobic pockets of debris.

That is why I recommend CaCl2. The other compounds (e.g., MgSO4) are used in lesser amounts, so the minor sulfate addition is not as problematic.

A mesh bag of finely crushed coral or oyster grit in the filter would be my second choice.
 

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Discussion Starter · #50 ·
I don't have any rules on this. Amount needed will depend on plant growth, water changes, amount of fish food, etc. That said, there's lots of leeway.

I would add it once as I described to "harden up" softwater--along with Ca and Mg-- or whenever you see deficiency symptoms.
 

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Discussion Starter · #52 ·
I wouldn't add any more baking soda. You don't want to inhibit plant growth with excess sodium--unnecessarily. Your KH and pH are acceptable.
 

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Discussion Starter · #62 ·
I don't see why it wouldn't work. 95% odds that it will work fine; 5% that it will not...

The main ingredient is KCl and I assume the minor ingredients like sugar would be present in only small amounts. None of them should cause a problem, chemically speaking.
 

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Discussion Starter · #64 ·
For correcting softwater deficiencies in tanks already set up, my recipe (using CaCl2, MgSO4, KCl chemicals) does not add bicarbonates. This may be a deficiency. If your KH is 3 or below after the Ca, Mg, and K additions, I would consider adding a little BS (baking soda). To increase KH by one degree, I see recommendations to add ¼ tsp BS to 13 gal or 1 gram BS to 10 gal. Sounds about right and dosage is flexible.
 

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Discussion Starter · #69 ·
I would add that bicarbonates are not just a pH buffer. They are a carbon source for many submerged aquatic plants, especially those native to hardwaters and can use bicarbonates. One aquatic botanist (Craig S. Smith, 1993) showed two-fold faster growth of two aquatic plant species when bicarbonates were added to a nutrient solution.
 
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