GH and KH Buffering Experiment.

[jarrod0987]

I decided to see just how much Calcium Carbonate really buffers GH and KH. GH in freshwater is referred to as hardness and is approximately 75% Calcium and 25% magnesium in my experience. Calcium Carbonate can be shells, crushed coral, aragonite sand, oyster grit, and perhaps other shell material I have not thought of. In this case I used Oyster Grit. The Brand was Mana Pro Oyster Shell bought at a local hardware store. It is sold for use with raising chickens.

I started with RODI water which has a GH and KH of 0 DKH. I filled a mug with this water and put 1 cup of oyster grit in the bottom. I let it sit for 5 days. API GH/KH test kit shows GH is now 6 DKH and KH is now 4 DKH. These values are low but not unusable for a planted tank. It would be nice to know that this was the lowest a tank could go. Like a safety measure. The tank cannot go acidic. It may very well be that even at these low levels that as long as calcium , Magnesium, and Bicarbonate are available in the water that no addition would be needed. Diana Walstad states in her book she uses this method. It is self regulating and therefore very convenient.

 

[coralbandit]

I remineralise my ro/di with calcium chloride(kent turbo calcium),Epsom salt(mgso4),bicarbonate and a touch of marine salt!
I can set my water wherever I want easily.
I use this mix for my GBR breeding tanks and fry/juvi growouts.

 

[jarrod0987]

Perhaps you could share your recipes and target levels with the people who would like to do that? I have some receipts from D. Walstad but never tried them out yet. What amount do you add to raise a gal 1 dkh etc.

 

[trennamw]

I like Walstads recipe but find it easier to use API Buffer Max (meant for African cichlids) and Seachem Equilibrium. Low doses of each to get GH to 4-5 and KH at 3-4. The ph is 7-7.5 depending on the tank.

Those two are cheap and easy to find, no buying big quantities of stuff and mixing. And I like that the Equilibrium has a wide variety of minerals plants and fish need.

Our LFS uses "cichlid" buffer in all their community tanks too, at a 1/3 dose, because our tap has zero KH.


Sent from my iPhone with three hands tied behind my back.

 

[ScotJudd]

Hi.
My tap water is V soft, Gh and Kh undetectable using API liquid test kit. I add 2.5ml (half a teaspoon) of Equilibrium and the same of Bicarbonate of Soda to each new bucket of tap water (about 2 gallons or 10 litres). This gives me Gh and Kh of about 6. Ph sits at about 7 - 7.2 despite using Co2, which has a tendency to drop the Ph. I've been doing this for two years and tank is really stable. I use a 2.5 ml spoon and ensure its exact by running a knife across the spoon to ensure its neither a raised or dipped measure.
I keep a mixed selection of tetras, red cherry shrimp, Corey's and a BN and loads of plants. Shrimp are breeding like mad, Corys have had babies that reach maturity and the plants are growing and reproducing via runners.
IMO natural ways of hardening water works well for Gh but not so reliable for Kh. I also like the mix of minerals in Equilibrium which you don't get from shell or coral.


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[coralbandit]

I work my mix from this recipe I got from a"MissleBear" on TPT.



Originally Posted by MissileBear
My apologies for the late reply.
I use a 55 gallon drum for mixing my water. I end up adding an addition 5-6 gallons of RO during the water change which dilutes the prepared water slightly. I just purchased new test kits tonight; a fresh batch if water test results:

7-8* GH
4* KH
6.2 pH
TDS: 214 (this is higher than expected...maybe from the peat moss?)

This is a slightly harder, higher pH than normally found in the Amazon basin, but I find the water to become more acidic and softer by the time a water change is performed.

21.45 g CaCl2 x 2 H20
9.15 g MgSO4 x 7 H2O (epsom salt)

This provides a 4:1 Calcium to Magnesium ratio.

To get the KH to about 4*, I mix 14.05 g baking soda. This also increases the GH a bit.

I throw in about a teaspoon of marine salt for the extra micros you don't get elsewhere. A filter bag full of peat moss is soaked for the duration of the water sitting, and I add about a 2 tablespoons of lemon juice. The water is bubbled for at least 24 hours after mixing.

I skip the peat and lemmon juice .
I mix slightly less of each ,but clearly at this point "exploration" is part of the game!
Hope this helps someone out!

 

[jarrod0987]

I have found that using 5 handfuls of Oyster Grit in my 20 gal tank (15 gal of actual water) the GH is 10 and the KH is 8 after about 2 weeks of breaking in. This is much more desirable then the lower numbers after a week in RODI. Temp was 75.7 F and pH was 7.66.

 

[Autumnsky]

Appreciating the helpful info on this subject - on something that has been giving me trouble personally. Extra thanks to all the contributors. I am soon needing to buy more additives myself, and these are great suggestions and "recipes" for me to consider too.

 

[jarrod0987]

Appreciating the helpful info on this subject - on something that has been giving me trouble personally. Extra thanks to all the contributors. I am soon needing to buy more additives myself, and these are great suggestions and "recipes" for me to consider too.

After this recent discovery of using oyster grit (Crushed Coral probably works fine) I think I will never add Calcium or alkalinity to my freshwater tanks again. I have recently read a claim from a very reputable person this also adds potassium. I was shocked and I don't believe it. I am going to test as soon as my K test comes in. Will let you all know the results.

 

[Delapool]

After this recent discovery of using oyster grit (Crushed Coral probably works fine) I think I will never add Calcium or alkalinity to my freshwater tanks again. I have recently read a claim from a very reputable person this also adds potassium. I was shocked and I don't believe it. I am going to test as soon as my K test comes in. Will let you all know the results.

Be curious if it does the calcium carbonate formula (maybe plus magnesium) kind of counts it out I'd have thought.

What test kit are you using for K? Just curious as using coral shop potassium test kit here to read k in the lower values found in freshwater.

Ps - great experiment and read too!!

 

[jarrod0987]

Be curious if it does the calcium carbonate formula (maybe plus magnesium) kind of counts it out I'd have thought.

What test kit are you using for K? Just curious as using coral shop potassium test kit here to read k in the lower values found in freshwater.

Ps - great experiment and read too!!

I couldn't find a freshwater K test either. So weird because planted tank people need that one. I have used red sea colors pro set in the past but I gave it away when I moved. I have the potassium pro test on order. Same thing just by itself. I am with you..Calcium, Cabonate, bicarbonate, Mg perhaps a touch of Strontium fine. Potassium?? Really?

 

[trennamw]

I'm with Scott Judd. The natural approaches to KH just aren't easy, exact, reliable ... And it's a different mix of nutrients than equilibrium and a buffer (cichlid buffer is basically sodium bicarbonate and one other thing).


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[trennamw]

I have found that using 5 handfuls of Oyster Grit in my 20 gal tank (15 gal of actual water) the GH is 10 and the KH is 8 after about 2 weeks of breaking in. This is much more desirable then the lower numbers after a week in RODI. Temp was 75.7 F and pH was 7.66.

Why do you say the GH and KH at 8-10 is more desirable? I don't find this to be the case unless you have fish who need it.




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[jarrod0987]

Why do you say the GH and KH at 8-10 is more desirable? I don't find this to be the case unless you have fish who need it.




Sent from my iPhone with three hands tied behind my back.

I am following the recommendations of Dr. Walstad in her book for this tank. She likes higher numbers for hard water species etc. The other numbers where way to low.

 

[jarrod0987]

Update: sort off I read somewhere recently someone claiming that Potassium can be released from Acidic water dissolving Calcium Carbonate. AKA crushed Coral or in my case oyster grit. I know you get some Mg with this deal but K....I was very skeptical. I soaked some oyster grit (pre rinsed) in DI water for a week and then tried testing with Red Sea's Potassium Pro test kit. It's only really made for sea water and the range is way off. So the results were pretty much useless. Got a color change at 1.5 ml of reagent D. So basically it could be as much as 20 ppm of potassium present. However my freshwater aquarium gave the exact same result. I don't believe the test is accurate when used in this way. I don;t believe the results can be trusted. I don't believe there is Potassium released from dissolving crushed coral. I looked for a proper K test kit for freshwater in this range but no luck. Not even at Lamotte website

 

[Delapool]

It is strange there isn't a proper k test kit for freshwater. Even the coral shop test kit I wonder if it reads high as struggle to get values below 100ppm (although do k dose a lot).

Loving all the testing and results by the way.

 

[jarrod0987]

It is strange there isn't a proper k test kit for freshwater. Even the coral shop test kit I wonder if it reads high as struggle to get values below 100ppm (although do k dose a lot).

Loving all the testing and results by the way.

Your welcome. I just spent all night playing with a Red Sea Pro Potassium test kit in fresh water. It's expensive as far as tests go. Time consuming, a PITA, and the range is just wrong. Can't get a reading that I trust due to the range and resolution the test was designed for.

I read on Tom Bar's website that K is just really hard to test for. I agree, even in sea water the tritration is easy to mess up. I guess it is just easier and less hassle to dose and dump every week. I wish there was a good test kit too. I even checked at Lamotte and Hanna Instruments. I did not see anything that doesn't cost a fortune.

 

[Delapool]

Yes, I think this one was about $70 but worse yet - only lasts a year. The test is not too bad when used to it but looking at 5 little bottles and syringes at the start a bit daunting.

K just doesn't seem to get much interest. Doesn't seem so much of an issue for fish although not 100% sure there, just reading on Tom's website again. I don't know if I will get it again. Somewhere down the wish list after getting a second CO2 bottle.

 

[jarrod0987]

Yes, I think this one was about $70 but worse yet - only lasts a year. The test is not too bad when used to it but looking at 5 little bottles and syringes at the start a bit daunting.

K just doesn't seem to get much interest. Doesn't seem so much of an issue for fish although not 100% sure there, just reading on Tom's website again. I don't know if I will get it again. Somewhere down the wish list after getting a second CO2 bottle.

I'm sorry, I did not understand. What are you referring to that costs 70$ and lasts a year?

K is only important to plants and corals. EI, ADA, and Walstad systems don't test for it. Maybe because they can't Just kidding.
Coral people mostly don't know or test for it. However, Red Sea came out with some awesome research and products for it that have to do with coral coloration. I actually bought 2 of those kits now but It can also be does by calcium uptake which I test anyways. I am so going to try it that way from now on. K test is a PITA!!

 

[Delapool]

I'm sorry, I did not understand. What are you referring to that costs 70$ and lasts a year?

K is only important to plants and corals. EI, ADA, and Walstad systems don't test for it. Maybe because they can't Just kidding.
Coral people mostly don't know or test for it. However, Red Sea came out with some awesome research and products for it that have to do with coral coloration. I actually bought 2 of those kits now but It can also be does by calcium uptake which I test anyways. I am so going to try it that way from now on. K test is a PITA!!

Hope this helps. This is the FW K test kit I'm using. Makes the nitrate test look easy...

It's made by coral shop I think.


http://www.aquariumadvice.com/forums/f60/coral-shop-potassium-test-kit-331838.html