GH and KH questions

[mrsjoannh13]

I have been using test strips to measure my tank's GH and KH for the past couple of months. In ppm I have been reading about 25 ppm GH and about 125 ppm KH. In order to get a more accurate reading I ordered the liquid test kit for GH & KH from API and got that in yesterday.
It's the test where you add one drop then invert a few times and however many drops it takes to change the liquid color is how many degrees of hardness you have.

For KH I had to put in 8 drops to get the color change so that is 8 degrees of hardness (which I believe is about 142 ppm).

For GH with only 1 drop the liquid was at the second color - meaning I didn't have to put in 2 or 3 drops to get the color to change (I think it should have gone from orange to green but just immediately turned green with one drop). So that's 1 degree of general hardness or just about 18 ppm.

So far my fish have been doing great (glofish tetras) so I believe the hardness parameters are okay for them. However, I'm setting up my 2nd tank with plants and wondering if the low GH will cause any issues for live plants? I did just plant the tank about a week ago and everything is looking good so far. But could the GH be problematic over time?

Also I thought generally GH and KH were fairly similar. So any thoughts on why the 2 are so different?

For the 2nd planted tank, stocking thoughts are 6 sterbai corys and 1 betta.

Thanks!

 

[Yohance1130]

I have been using test strips to measure my tank's GH and KH for the past couple of months. In ppm I have been reading about 25 ppm GH and about 125 ppm KH. In order to get a more accurate reading I ordered the liquid test kit for GH & KH from API and got that in yesterday.
It's the test where you add one drop then invert a few times and however many drops it takes to change the liquid color is how many degrees of hardness you have.

For KH I had to put in 8 drops to get the color change so that is 8 degrees of hardness (which I believe is about 142 ppm).

For GH with only 1 drop the liquid was at the second color - meaning I didn't have to put in 2 or 3 drops to get the color to change (I think it should have gone from orange to green but just immediately turned green with one drop). So that's 1 degree of general hardness or just about 18 ppm.

So far my fish have been doing great (glofish tetras) so I believe the hardness parameters are okay for them. However, I'm setting up my 2nd tank with plants and wondering if the low GH will cause any issues for live plants? I did just plant the tank about a week ago and everything is looking good so far. But could the GH be problematic over time?

Also I thought generally GH and KH were fairly similar. So any thoughts on why the 2 are so different?

For the 2nd planted tank, stocking thoughts are 6 sterbai corys and 1 betta.

Thanks!

The low gh may cause an issue for your plants overtime since plants need 3-6 degrees of GH. But the Gh might not also cause a problem for the plants just watch them for now. You should have gotten a paper like this in your api GH and KH test kit.

The more higher your KH is the less chance your ph in your tank will fluctuate, the lower your KH is the more your ph will fluctuate. The goal is to keep your ph as stable as possible in any aquarium since our aquarium fish like stability and not a lot of change. The more your ph changes constantly the more your fish will be stressed and when they are stressed they are more successible to diseases and can possibly die. your KH is kind of like a barrier the more higher it is the more stable and constant your ph will be and blocks the ph from fluctuating. But if it is low the more your ph will change and will fluctuate.

The gh in your aquarium is the amount of calcium and magnesium ions present in your aquarium. Gh helps make your aquarium fish have strong bones. And helps improve the strength of their bones. The higher it is the more it well help. The GH in your aquarium is also really important for invertebrates like shrimp since it helps them with their molting process. If your gh is too low it well negatively impact invertebrates since it we'll prevent them from molting properly and if the invertebrates can't molt they will die. it well not negatively impact your fish to the point were they can die. But our goal is to make sure our aquarium fish are thriving. I would at minimum try to bump your GH to 3 degrees since that will be enough to keep most commonly available aquarium fish and plants and it we'll keep them comfortable. If you are looking to keep invertebrates like shrimp you will have to increase your GH to around 6 degrees.

Here is a care chart for the most commonly available shrimp in the aquarium hobby

 

[mrsjoannh13]

The low gh may cause an issue for your plants overtime since plants need 3-6 degrees of GH. But the Gh might not also cause a problem for the plants just watch them for now. You should have gotten a paper like this in your api GH and KH test kit.

Thank you so much for this information - very helpful. What would you recommend to raise GH without impacting pH (my pH is already pretty high and I use peat granules to get it in the mid-7's). It looks like Seachem Equilibrium might be an option?

 

[mcordelia]

I recently read some nice explanations by @StevenF on this topic, hopefully he has a chance to respond here as well.

 

[StevenF]

Also I thought generally GH and KH were fairly similar. So any thoughts on why the 2 are so different?

Depending on the chemistry of your water The GH and KH could be the same but often they are not.

The GH test detects calcium and magnesium but it doesn't tell you the molecular form it is in. Typically inn an aquarium it will detect
Calcium chloride
Magnesium chloride
Calcium sulfate
Potassium sulfate
Calcium carbonate
Magnesium carbonate.

The GH test can detect other calcium / Magnesium compounds I haven't listed..

The KH test detects carbonate salts such as:

Calcium carbonate
Magnesium carbonate
potassium bicaronate
Sodium bicarbonate
lithium bicarbonate.
Ammonia carbonate

Again there are a number of other carbonates the KH test could detect.

Note that Calcium and magnesium carbonate appear in both the GH and KH lists. These compounds are typically found in well water. So well water might tests as having equal GH and KH..

However when a utility sterilizes the well water with chlorine some of the carbonate will be converted to calcium and magnesium chloride. The would lower the KH reading but the GH reading would not change.

Surface water will typically have a mix of GH and KH salts and as a result you cannot assume the GH and KH vales would be the same. But since surface water is also sterilized with Chlorine tap water will also typically have a lower KH reading then GH.

An additional factor is that many water utilities add stuff to the water to help prevent pipe corrsosion. Sometimes potassium sodium bicarbonates are added to the water to increase PH and suppress pipe corrosion. So in some places the KH may be much higher than the GH.

Also some homes have water softener installed to convert hard water to soft water. These devices will lower GH by removing calcium and magnesium but will replace that with sodium bicarbonate. Your GH and KH number are sonsistant with a water from a water softener. Or your utility may be adding carbonates to naturally soft water to prevent pipe corrosion.

So far my fish have been doing great (glofish tetras) so I believe the hardness parameters are okay for them. However, I'm setting up my 2nd tank with plants and wondering if the low GH will cause any issues for live plants? I did just plant the tank about a week ago and everything is looking good so far. But could the GH be problematic over time?

All life on earth needs calcium and magnesium for growth. If you water is short on just one your plants will not grow. The GH test does detect calcium and magnesium but it won't tell you if you have just calcium, just magnesium. or some of each.

So if your water ihas mostly calcium you could run short on magnesium. It is my understanding that calcium is typically abundant in well water with little magnesium. Or you could've havevery soft surfacewater, which is what your GH test indicates, and end up with your tank being rich in magnesium (present in most fertilizer) with deficient calcium (fertilizers typically don't have calcium).

It is possible to have healthy plants with only 1 degree of hardness is you get the calcium magnesium ratio very close to what your plants need. But if your calcium to magnesium ratio is off by just a little bit you can have problems. But since we don't know the exact ratio for each type ofplant in an aquarium it is easier to overdose Ca and Mg by aiming for a GH of 3 to 6 degrees.

However it is often better to use a target a GH value that suites your fish rather than your plants. If you are stocking a tank with fish that have a genetic preference for hard water, it is better to target a higher GH level.

But could the GH be problematic over time?

In a new tank the substrate may have some calcium and magnesium but that supply will probably run out eventually. So if your substrate has some GH in the plants can use that even though your tap water may not have enough. But eventually plant growth may slow a when the substate gh runs out. Sometimes that happens in weeks. in other cases it can take 1 to two years.

What would you recommend to raise GH without impacting pH (my pH is already pretty high and I use peat granules to get it in the mid-7's). It looks like Seachem Equilibrium might be an option?

Equilibrium is mainly calcium sulfate and magnesium sulfate. If you put that in water you generally will not see any change in PH. Other GH boosterer use calcium and magnesium chloride and also don't affect ph. But plants need a calcium and magnesium but very little sulfur and even less chloride. So in my tank the sulfates tend to build up in my tank. If I don't take corrective actions my PH will drop to 5 over time. But depending on your water chemistry it is possible to see the opposite. A pH rise due to plant growth. I cannot predict what you will see. But in my case my solution was to put a sea shell (mainly calcium carbonate) in my filter. Along with weekly water changes This has kept my PH at 7 even though my KH is less than 1.degree. I don't know what you can do to to counteract a gradually increasing PH.

 

[Yohance1130]

Thank you so much for this information - very helpful. What would you recommend to raise GH without impacting pH (my pH is already pretty high and I use peat granules to get it in the mid-7's). It looks like Seachem Equilibrium might be an option?

Yes no problem. Im not exactly sure since I never had to raise my GH in my aquarium but I think Seachem Equilibrium will work. Just make sure you test your water when you use equilibrium to make sure the GH level stays balanced and does not fluctuate a lot. You can test your GH level every time you add equilibrium in your tank for around a month just to be on the safe side and so that you have an idea of how much will need to be added in your aquarium.

 

[mrsjoannh13]

Yes no problem. Im not exactly sure since I never had to raise my GH in my aquarium but I think Seachem Equilibrium will work. Just make sure you test your water when you use equilibrium to make sure the GH level stays balanced and does not fluctuate a lot. You can test your GH level every time you add equilibrium in your tank for around a month just to be on the safe side and so that you have an idea of how much will need to be added in your aquarium.

Thanks again for the input! I have a tank that I fill up in advance for water changes so I'll put the equilibrium in the holding container and see how much it impacts GH.

 

[Yohance1130]

Thanks again for the input! I have a tank that I fill up in advance for water changes so I'll put the equilibrium in the holding container and see how much it impacts GH.

Good Idea! Hope everything works well for you!?