[Wet Thumb Forum]-Calcium dosing to increase GH

[CraigThor]

Diana I wonder if you or anyone is still using CaCL2 for adjusting there tanks.

I have 2 lbs of CaCL2 and am wantign to use this method to avoid a PH increase.

I know this is an old post but seems to have alot of good info.

Craig

[Seattle_Aquarist]

Hi CraigThor,

I use CaCl2 for my tanks and have no problems. I know some people have expressed concern about the chloride being a problem for the fish or plants, but I have not experienced any problems using it.

I tried CaSO4 and CaCl2 and found I liked CaCl2 better because it dissolves clear while CaSO4 was "milky". One warning if using CaCl2, the chemical reaction with water is quite strong and generates heat. Add the CaCl2 to water, do not add add water to CaCl2; and do not be surprised if the glass you are mixing it in becomes warm. I would not add CaCl2 directly into my tank for fear the fish might try to eat the crystals before they dissolved.

[CraigThor]

Originally Posted by Seattle_Aquarist

Hi CraigThor,

I use CaCl2 for my tanks and have no problems. I know some people have expressed concern about the chloride being a problem for the fish or plants, but I have not experienced any problems using it.

I tried CaSO4 and CaCl2 and found I liked CaCl2 better because it dissolves clear while CaSO4 was "milky". One warning if using CaCl2, the chemical reaction with water is quite strong and generates heat. Add the CaCl2 to water, do not add add water to CaCl2; and do not be surprised if the glass you are mixing it in becomes warm. I would not add CaCl2 directly into my tank for fear the fish might try to eat the crystals before they dissolved.

Thanks. The Chloride is what I was wondering about. I've been told by several not to use it because of too much chloride.

I also did order some CaSO3/4 dont remeber which from Aquariumfertilizer.com also. I will be using it in my shrimp nanao tank as a form of calcium for the shrimp and snails

Craig

[dwalstad]

Originally Posted by CraigThor

Thanks. The Chloride is what I was wondering about. I've been told by several not to use it because of too much chloride.

I also did order some CaSO3/4 dont remeber which from Aquariumfertilizer.com also. I will be using it in my shrimp nanao tank as a form of calcium for the shrimp and snails

Craig

I do not recommend adding sulfates to NPTs, especially those with a potting soil or organic substrates. H2S generated from sulfates in the anaerobic environment is highly toxic to plant roots.

Chloride is only inhibitory in massive amounts, much less than what you need to add for increasing water hardness. For example, to bring GH up to my water's hardwater levels, you would need to add 30 ppm of CaCl2. This addition would bring with it 60 ppm of chloride. This is 60 mg/l, which is only 0.006% chloride. Plants are inhibited by salt (sodium chloride) at 0.1%.

Bottom Line: The amount of chloride you're adding to get GH up to increase water hardness is much less than what would inhibit plants.

If you have a clay or gravel substrate with no organic matter, CaSO4 will probably cause no problems. But in an NPT with an organic soil, you risk getting reduced plant growth and other problems.

[CraigThor]

Originally Posted by dwalstad

I do not recommend adding sulfates to NPTs, especially those with a potting soil or organic substrates. H2S generated from sulfates in the anaerobic environment is highly toxic to plant roots.

Chloride is only inhibitory in massive amounts, much less than what you need to add for increasing water hardness. For example, to bring GH up to my water's hardwater levels, you would need to add 30 ppm of CaCl2. This addition would bring with it 60 ppm of chloride. This is 60 mg/l, which is only 0.006% chloride. Plants are inhibited by salt (sodium chloride) at 0.1%.

Bottom Line: The amount of chloride you're adding to get GH up to increase water hardness is much less than what would inhibit plants.

If you have a clay or gravel substrate with no organic matter, CaSO4 will probably cause no problems. But in an NPT with an organic soil, you risk getting reduced plant growth and other problems.

Diana,

Thanks. My tank is actually a high tech tank but I'm trying to eliminate any ph swing that adding chemicals can occur as its also my shrimp tank. I added about 3/4 tsp of both MgSO4.7H2O and CaCL2 to get my tank 5g up to where I want it atleast by the math (also by the fertilator) no test kit yet. I use the ADA Aquasoil in my tank with pure RO water and needed to add Ca and Mg for my shrimp and snails.

I had a chat with Ray Lucas (Kingfish Services) this weekend and he told me he had done a talk on NPT and was fortuante enough to meet you afterwords.

Thanks for posting your input as everyone is telling me that the Chloride is harmful for the tank. I have 2 lbs of it so I would love to use it.

Craig

[colinsk]

If you are using RO water I would consider CaCO3 instead of CaCl.

[CraigThor]

Originally Posted by colinsk

If you are using RO water I would consider CaCO3 instead of CaCl.

Any reasoning behind that?

[colinsk]

Any slight addition of H+ in the water will make large pH swings unless you have some kH (alkalinity, carbonates, CO3, for this discussion we can consider them the same). An RO unit removes almost all of the kH. Normal biological processes tend to want to swing the pH lower and having some CO3 as a buffer is a good idea to keep your tank from swinging pH. In a few hours you could go from 6 to 5 pH. I prefer to run around 7 and have both fast and slow buffers in the tank. I use CaCO3 as a fast buffer (from my tapwater) and oyster shells as a slow buffer. This gives me time to notice a problem before it is a big problem. I still keep my kH fairly low at 4 but it is much better than 0.

[dwalstad]

I have no problem with either CaCl2 or CaCO3. However, Colinsk has a good point. If you have R.O. water, it probably doesn't have any bicarbonates. You could use CaCO3 to add bicarbonates to the water and increase the buffering capacity. However, the easiest thing to do would be to add baking soda (sodium bicarbonate) to get KH up and CaCl2/MgSO4 to get GH up.

Here, we realize that its tough to duplicate hard water with its main ingredients, which are: bicarbonates, calcium, magnesium, and potassium. These are all major plant nutrients and pH buffers. On page 87 of my book, I suggest additions for those with ultra-soft water.

I don't advocate using R.O. water for planted tanks unless there's a real and identified toxin that you have to remove. Why remove all the natural hardwater salts and then have to put them all back later on?

[colinsk]

Originally Posted by dwalstad

Here, we realize that its tough to duplicate hard water with its main ingredients, which are: bicarbonates, calcium, magnesium, and potassium. These are all major plant nutrients and pH buffers. On page 87 of my book, I suggest additions for those with ultra-soft water.

At work I have to do this everyday. I have to emulate the brewing waters of the world. I have a very good spreadsheet and lots of acids and salts. I would rather start from tap water but I also can start from RO or DI water if I need to. I would not choose to do this with fish. If my water was very hard, like from the Great Salt Lake, then I would dilute with RO but starting from scratch is very hard.