# KH & GH questions



## driftwoodhunter (Jul 1, 2011)

Hi ~
trying this again, I had 111 views last time but no takers! 

I have purchased a KH & GH test kit. Now that I have the results, I need help understanding them. The tank is a 125g, the GH is 6 and the KH is 3 and the pH is 6.8 to 7.0 (the colors are so darned close on the chart). I keep 95% tetras so this is within their range if I understand the kit's instructions correctly. However my snail's shells erode as they mature, and they die. I purchased a cuttlebone but I haven't used it yet. I also have calcium montmorillonite clay coming in soon. Both of these I got because threads about eroded snail shells mentioned they may help. 

Does anyone know how cuttlebone or montmorillonite clay effect GH & KH & pH? I've read that I should try to get the GH & the KH as close to equal as possible, but I don't know how to effect one and not the other, plus I don't want to raise the pH.

Any tutoring would be welcomed!


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## danielt (Dec 19, 2012)

I'll give it a shot. From what I know cuttle bone raises kH but not gH.

Also, pH is raised or rather prevented to go lower by kH. If you raise kH it will have an impact on pH.

gH will not raise pH there is no connection between these two. kH can be raised independently of gH by adding baking soda.

gH can be raised independently of kH by adding Calcium Chloride, Calcium Sulfate and Magnesium Sulfate

Your snails are suffering because the water drains minerals from their shell as it is, most probably, too acid for them. Snails can get their minerals from what they eat and the water itself if it has the right parameters which yours doesn't. On a side note, plants benefit from this water as acid, low kH water is better for some of them.

Clay helps but it doesn't have much Calcium in it. Gipsum (aka Calcium Sulfate) is a good material if you don't want to spend money on commercial products.

I'm using RO water in all my tanks and one of them does not receive anything than fish food but it's full of snails that do pretty good.


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## driftwoodhunter (Jul 1, 2011)

danielt, thank you so much for the clear explanations! 

Since my tetras can handle a slightly higher pH, it sounds like I can gently raise my KH - thereby preventing my pH from dropping, but raise my pH slightly instead - which will help my snails by reducing the acidity of my water.

I will try to raise the KH a tiny amount by using the cuttlebone I have, and see if I can strike a happy balance for the snails, fish, and plants.

Thank you so much for responding to my post :smile:


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## Darkblade48 (Jan 4, 2008)

danielt said:


> I'll give it a shot. From what I know cuttle bone raises kH but not gH.


Cuttlebone will raise both kH and gH.


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## driftwoodhunter (Jul 1, 2011)

So I should skip the cuttlebone and try a pinch of baking soda if I only want to raise the kH ? 

Here is a link to an article I've only just started reading - however this caught my eye (the italics are theirs) since I don't add co2 to may tanks...
"KH (carbonate hardness) is an important source of energy for nitrifying bacteria that eliminate ammonia and nitrite. In addition, carbonates may be used by plants for photosynthesis when carbon dioxide (CO2) is absent."

and the link to the article if anyone's interested. They do push Seachem buffers rather than baking soda, but this is a sales site; http://www.americanaquariumproducts.com/aquariumkh.html


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## driftwoodhunter (Jul 1, 2011)

Perhaps I've had the wrong idea of what my fish need all along. Some searches come up with these general ranges for my main tank inhabitants; 

*Buenos Aires Tetra;*
pH: 5.8-8.5
Hardness: to 35 dGH


*Colombian Tetra;*
pH : 6 - 7
Water Hardness : 6° to 15° dH (I assume that's dGH?)

if so, my GH at 7 could go higher, as well as my KH - but keeping the pH in the Colombian Tetra's range might require a bit of peat, oak leaves, etc. if it goes too high. I already have massive amounts of driftwood in there, so maybe that will buffer sufficiently.


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## danielt (Dec 19, 2012)

Driftwood does not buffer, it's the opposite as tannins and other organic acids are slowly released in the water they will bind the bicarbonate making the pH to slowly creep downwards.

General rule when it comes to fish is that they tolerate higher gH if they're soft water fish but not the other way around. kH will not do anything to fish.

Forget about the pH and don't regulate your changes based on it. The americanaquarium website is a good source of valuable information. Although I will slam a bit that statement. Carbon is not a source of energy for anything. There are two sources of energy in the aquarium as far as my understanding goes: Light and Chemical reactions

Nitrifying bacteria use nitrogen oxidation to get the energy and use C for food.

ALL plants prefer CO2 before carbonates. Don't rely much on the statement they use carbonates. Some of them don't use them at all and some use it as a last resort.

In general soft water plants will not use carbonates at all. The hard water plants have adapted to use the plenty carbonates that exist in hard water.

A ph of 6.8 - 7 is good for just about anything. I'll go as far as saying that just feeding the snails a good amount of calcium can compensate for the acidity of the water.

One last thought, search on the forums for Diana's posts. I saw her replying to many threads like yours, it's a starting point to find out more about the water chemistry. You can look at my posts as well but I'm not that experienced.


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## wkndracer (Mar 14, 2009)

driftwoodhunter said:


> Hi ~
> trying this again, I had 111 views last time but no takers!
> 
> I've read that I should *try to get the GH & the KH as close to equal as possible*, but I don't know how to effect one and not the other, plus I don't want to raise the pH.
> ...


With all the comments recommending this try to find anything that provides a real reason why it's required.
Posting you have water testing at 6dGH & 3dKH I would knock holes in the ceiling jumping up and down for joy if I had those values available here for source water. 

Provide foods rich in Calcium for your critters and the shell issues will stop. I have Briggs (trap doors) kept in 3-5dGH and 2dKH remineralized RO with no shell issues simply by feeding correctly. 

pH concerns are basically last years reference for water quality. 
Having the equipment here I've placed electronic pH controllers on low light NPT systems just to see what happens during a 24hr period (used them as simply a monitor). Lighting alone can shift tested pH by a full degree on soft water tanks. Monitoring what the pH reading was in the morning before the photoperiod and again late in the afternoon I recorded a full point shift in value. The only difference was lights on or lights off (more or less CO2 in solution). 
Shifts in pH don't really effect our critters and happen in nature all the time.

Water is better understood when defined by it's mineral content, that's what the critters are living in.
Shifts in GH, KH, TDS, (changes in osmotic pressure) that's what effects our critters not a pH value or change in pH per say.
Again a tank tested pH value is the product of carbonate buffers and CO2 content in the water. Acidic or alkaline yes but testing pH as it relates to tank water ignores mineral content. Mineral content effect critters.


danielt said:


> Forget about the pH and don't regulate your changes based on it. The americanaquarium website is a good source of valuable information. Although I will slam a bit that statement. Carbon is not a source of energy for anything. There are two sources of energy in the aquarium as far as my understanding goes: Light and Chemical reactions
> 
> A ph of 6.8 - 7 is good for just about anything. I'll go as far as saying that just feeding the snails a good amount of calcium can compensate for the acidity of the water.
> 
> One last thought, *search on the forums for Diana's posts*. I saw her replying to many threads like yours, it's a starting point to find out more about the water chemistry. You can look at my posts as well but I'm not that experienced.


Posting that parameters of mineral content needed to be closely matched was Diana's take on the topic and mine the inverse.
First I PM'ed a couple times asking why this was her position then we posted in thread conversations on the topic several times in answer to others members asking (as my sister of the dirt has here) I smiled drinking coffee and reading opinion this morning.


Diana said:


> Plants need 16-17 different elements to grow.
> GH measures Ca and Mg, so if the GH is roughly 3 degrees or higher there is plenty for plants.
> KH measures carbonates. This is a buffer for pH. The old thinking was that you needed at least 3 dKH for a stable pH. I have stable tanks with no KH showing on my tests. (No, the test is not old)
> *If you can get the RO + tap blend to the GH of 6 and KH of 2, I think that should be fine* for the plants, and OK for most soft water fish.


First time I've read her posting agreement on my stated position for this topic LOL always before it was mix to closely matched values :icon_cool 
http://www.plantedtank.net/forums/showthread.php?t=225226

living is learning


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## driftwoodhunter (Jul 1, 2011)

And here I was thinking my water was bad! I wish I could remember where I saw the posts on getting the KH and the GH to equal. It must have been some of the very last things I've read on the subject - I know that because I've remembered them, lol. I usually only remember the most recent things I read. It's very nice to find out that somehow I've stumbled blindly onto something good in my tank - I'll start testing my others, as well as my tap just for kicks.

As far as feeding the snails, I try. I bought some sinking veggie sticks with added calcium, but the first time I put them in the tank the Buenos Aires and Columbian tetras ate 90% of it. They swam around like little gangsters with cigars until the sticks softened enough to eat. (I admit I was worried about choking). I fed again yesterday and I actually saw snails eating the sticks - the fish only got about 1/2 of it that time. But the fish pick them off the bottom, even pushing a snail off to get the stick. I'm feeding the fish veggies several times a week now, so it's not that they are starved for greens...

The sticks are rather expensive when the fish eat them so fast - if it was just the snails I could justify the cost. I'd like to learn to make my own. I did break up small pieces of the cuttlebone hoping the snails will cruise it once it sinks - and I put a big piece in the filter - I may remove it, I'll see how it effects the water first.

Ok, well I'm not going to tinker with the water in that tank now that I have more info and I'm starting to understand these relationships ~ thank you for all your help!


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## KH2PO4 (Jul 18, 2009)

Have you tried feeding the snails after light off? 
But that won't work if you have Cories.... :icon_neut


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## driftwoodhunter (Jul 1, 2011)

No, I haven't tried that - I will tonight. I have had a bit of luck by feeding the fish flake at one end of the tank, then dropping the pellets on the other so they might be missed by the fish who are busy elsewhere. I'll combine that with a lights out feeding tonight. I do have one green cory (I know, my bad) and I don't mind if it gets some of the pellets - it's just the big tetras eating most of them gets annoying (although good for the fish I suppose).


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## danielt (Dec 19, 2012)

@wkndracer

I agree with your point that gH and kH should not be equal. They do different things and they have no relationship with one another besides CaCO3.

I advised searching for Diana's posts more as a bookmark for discussions about water params.

@driftwoodhunter

My view on pH is that it's useless on telling what is wrong with your water. The fact it has so much focus puzzles me 

Whatever changes you do. Do them slowly as in weeks. I had Staurogyne melt in the span of a few days after bumping my gH considerably. Plants and fish do not tolerate quick changes but they can adapt.

Snails will feed on the remains from your fish. Or broaden the feeding area. When fish are occupied in one part of the tank snails will eat in the other.


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## driftwoodhunter (Jul 1, 2011)

danielt said:


> Snails will feed on the remains from your fish.


wow! I totally misread that and thought you said the snails would feed on the remains OF my fish - LOL

I don't have any plans to alter my water chemistry now - frankly I was concerned about trying because it it doesn't stay stable, all manner of problems would come my way. I feel much better, and more comfortable, about the tank now that I better understand some of the chemistry involved. I'm reading as much as I can, and understanding more and more - thank you everyone for all your help! 

I have let the small broken pieces of cuttlebone sink for the snails to find, and I will keep feeding the veggie/calcium sticks. Last time I fed the sticks, the ones that the fish didn't eat were swarmed by groups of snails - a rewarding sight!


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## danielt (Dec 19, 2012)

They will eat the remains of your fish as well. If it's soft, they will munch on it like mad. Don't think snails are picky. They eat whatever doesn't run from them and it's not hard.


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## Kdw1794 (Aug 4, 2021)

danielt said:


> I'll give it a shot. From what I know cuttle bone raises kH but not gH.
> 
> Also, pH is raised or rather prevented to go lower by kH. If you raise kH it will have an impact on pH.
> 
> ...


I have a question my water is hard so there's a lot of calcium, so I probably don't need to worry about putting a cuttlebone in my tank huh?


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## Deanna (Feb 15, 2017)

Kdw1794 said:


> I have a question my water is hard so there's a lot of calcium, so I probably don't need to worry about putting a cuttlebone in my tank huh?


This thread is 8 years old. So, you are unlikely to get a response from the posters. I will try to answer your question, but it may be better to start a new thread of your own.

You "probably" don't need the cuttlebone ...if your water is hard. Do you know the GH of your water? If not, the typical GH test kits are inexpensive. Make sure that you get the liquid type, not test strips. I suggest the Sera, Salifert or API kits. Although any hardness is likely calcium, which is what the cuttlebone provides, you also may need the right balance of magnesium in the "hardness." If you can provide your GH readings and what it is, in your tank, that you want the "hardness" for, we can be more specific. You might also contact your water company and ask what the calcium and magnesium levels are.


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## Phil Edwards (Jul 18, 2003)

Are you adding CO2? Depending on your pH drop/CO2 concentration you may see shell erosion from that. The best way I've found to keep snails and shells happy in my planted tanks is to add calcium, magnesium, and carbonate. Ca and Mg are essential plant nutrients that compose GH and carbonate/bicarbonate are your main KH contributors. 

What I've found in tanks _without_ CO2 addition is the same thing that happens in the wild; the plants tank up Ca and Mg and break down the carbonate/bicarbonate to get at the CO2 they contain. As the plants remove these from the water there's less available for your snails and they start getting shell erosion. I'd suggest adding Seachem Equilibrium at 1/3 dose (1 tsp/20 US gallons) once a week to start with and see how it goes. 

Also, adding an air stone will help improve CO2 concentration when the lights are on and help maintain consistent levels throughout a 24 hour period. 

Regards,
Phil


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## jake21 (Aug 11, 2019)

FYI: I have a high-tech tank with kh 3 and gh 7 and more than 40 mystery snails and all of their shells are fine; so i doubt the co2 is causing an issue.
-
This is the tank:


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