How to reduce KH and GH?

[martinmin]

My tap water changed recently. The KH and GH are very high. For example, KH is over 120 PPM measured by COOP test strip. Do I need to buy water to lower it? Or is there some chemical that can reduce it?

There are brown algae on my glass wall and I think that's due to bad water parametetrs.

Thanks

[Tony s]

On 7/7/2024 at 12:15 AM, martinmin said:

KH is over 120 PPM

Kh is actually really good right there. Gives you a lot of ph stability. Brown algae is caused by diatoms in the water. They feed off of silicates in the tank. And are completely normal for a new tank. Everyone gets it. Nerite snails are some of the best cleaners. It will go away once the silicates are used up. Unless you’re like me. I have sand in my well and continually add silicates. 
 

and don’t worry if you have hard wate. The majority of the US does. Completely normal. 

To give you an example. The water in the Midwest ranges from your 120 to over 300 in spots. Same with gh. And really the only sure way to change it is to use ro water. But if you only have 120 ppm, you’re mostly good.

[martinmin]

If I use ro water, do I need to use it every water change, every two weeks? Or is it a one time deal? 

[Tony s]

If you decide to use ro water, you’ll use it every time you do a water change. And if you have plants, you’ll need to add some kh and gh back in. Or you can do a partial mix of ro and tap. To target the numbers you’re after. But you have to be consistent. 
 

but honestly, it’s much easier to use tap for most people. Unless you’re trying to raise very sensitive species like German rams, apistos, discus, or wild caught South American ones. Most aquarium fish are either tank raised or farm raised. In water that doesn’t resemble the water from where the species comes from. So you’ll see a guide that says that they must have a low ph and soft water. For our aquarium fish that just isn’t true anymore. They’ve been adapted to harder water already. The only real exception to this is if you’re planning on doing a lot of breeding. Some South American fry actually do need the soft water. But the majority won’t.

 

[ange]

On 7/6/2024 at 11:57 PM, martinmin said:

If I use ro water, do I need to use it every water change, every two weeks? Or is it a one time deal? 

RO is one of those things where if you're using it you need to keep measuring your GH and KH to ensure that there are enough minerals for the life in the tank to remain healthy. Personally I like to use RO in tanks where most of the water that I add is due to replacing water lost to evaporation rather than water changes. I inherited a lot of tanks that had been receiving RO only for several years outside of rare cases and the only minerals added back in came from fertilizers. It was and still is a giant mess.

The saltwater side of the community is where I feel a lot of the benefits to RO shine in. There's very little reason to worry about it in freshwater as many of our hardness-related issues stem from too few rather than too many dissolved in the water column.

[JoeQ]

This article has a section on lowering KH

https://www.2hraquarist.com/blogs/ph-kh-gh-tds/kh-explained?_pos=1&_sid=2de35fca8&_ss=r

Edited July 7 by JoeQ

[Tony s]

On 7/7/2024 at 8:02 AM, JoeQ said:

This article has a section on lowering KH

I liked this. But I really liked the conclusion. It underscores the value of finding a good local fish store, or compatible source. And also points to using what you already have. Which is important for normal keepers. It makes everything so much easier. @martinmin the last thing we want to do is give you advice that complicates anything. When things get difficult, people quit. Nobody wants that to happen. 

Conclusions

Carbonate hardness determines whether you can keep sensitive plants that require low KH. While it is easy to raise carbonate hardness by adding limestone to the tank/filter, it is difficult to reduce Carbonate hardness from tap water. For most folks, it makes more sense to keep aquatic plants/livestock that are suited to your tap water parameters. For folks that are determined to keep softwater plants but have hard tap water, RO systems are getting cheaper and easier to setup.

[JoeQ]

On 7/7/2024 at 8:52 AM, Tony s said:

I liked this. But I really liked the conclusion. It underscores the value of finding a good local fish store, or compatible source. And also points to using what you already have. Which is important for normal keepers. It makes everything so much easier. @martinmin the last thing we want to do is give you advice that complicates anything. When things get difficult, people quit. Nobody wants that to happen. 

Conclusions

Carbonate hardness determines whether you can keep sensitive plants that require low KH. While it is easy to raise carbonate hardness by adding limestone to the tank/filter, it is difficult to reduce Carbonate hardness from tap water. For most folks, it makes more sense to keep aquatic plants/livestock that are suited to your tap water parameters. For folks that are determined to keep softwater plants but have hard tap water, RO systems are getting cheaper and easier to setup.

Imo plants & animals should be sourced as close as possible for a higher likelihood of success.

A wise man @Mmiller2001once wrote: stock your tank with inhabitants (plants/animals) who like the soup you are serving, don't try to change your soup for the inhabitants.

[Mmiller2001]

On 7/7/2024 at 7:08 AM, JoeQ said:

Imo plants & animals should be sourced as close as possible for a higher likelihood of success.

A wise man @Mmiller2001once wrote: stock your tank with inhabitants (plants/animals) who like the soup you are serving, don't try to change your soup for the inhabitants.

My favorite quote from my idol, Gregg Zydec.

For lower KH and GH, cutting your source water with RO or distilled water is quite easy and not very expensive. Having an RO system is the way to go imo. They have a decent price tag to purchase but are cheap to maintain. Removing water unknowns is my choice, then adding back known PPM (GH,KH) makes the process easier, but this is a personal choice. I prefer to chase numbers because this is how I learned to set those numbers. Over time, I now can immediately identify water problems. Being able to eliminate unknowns helps when problems arise.

Again though. My and your choice really comes down to how far you want to take the hobby. Personally, I’m all in and want to have a tank that places near the best tanks in the world and as such created a system to help me get there.

As far as KH, most plants have no problems with a bit of KH, I add no KH and my water has non measurable KH because the plants just do better with low pH and I also want to grow a few plants that absolutely require low PH. 
 

This tank has only been running for a few months at near zero KH, 6.2 degrees of GH. I also in choose live stock that thrive in these conditions.

Here is my last year competition tank also with no added KH.

 

[JoeQ]

On 7/7/2024 at 9:46 AM, Mmiller2001 said:

My favorite quote from my idol, Gregg Zydec.

One of my favorite and most useful quotes, the other most helpful nugget of wisdom is realizing that this 'aquarium game' is all about keeping healthy water. It is just a happy lil coincidence that these beautiful plants&animals thrive in the box holding the water! 

[martinmin]

On 7/7/2024 at 6:46 AM, Mmiller2001 said:

My favorite quote from my idol, Gregg Zydec.

For lower KH and GH, cutting your source water with RO or distilled water is quite easy and not very expensive. Having an RO system is the way to go imo. They have a decent price tag to purchase but are cheap to maintain. Removing water unknowns is my choice, then adding back known PPM (GH,KH) makes the process easier, but this is a personal choice. I prefer to chase numbers because this is how I learned to set those numbers. Over time, I now can immediately identify water problems. Being able to eliminate unknowns helps when problems arise.

Again though. My and your choice really comes down to how far you want to take the hobby. Personally, I’m all in and want to have a tank that places near the best tanks in the world and as such created a system to help me get there.

As far as KH, most plants have no problems with a bit of KH, I add no KH and my water has non measurable KH because the plants just do better with low pH and I also want to grow a few plants that absolutely require low PH. 
 

This tank has only been running for a few months at near zero KH, 6.2 degrees of GH. I also in choose live stock that thrive in these conditions.

Here is my last year competition tank also with no added KH.

 

Hi, how did you get such a low KH, near zero? Is it just your tap water or you lower it to near zero someway?

 

Also, do you think cook and boil my tap water will reduce KH? 

[Mmiller2001]

On 7/7/2024 at 8:48 PM, martinmin said:

Hi, how did you get such a low KH, near zero? Is it just your tap water or you lower it to near zero someway?

 

Also, do you think cook and boil my tap water will reduce KH? 

I have a RO/DI system that takes my water to 0 TDS. I simply add no KH. I’ve never heard of boiling water to lower KH. It would probably raise it as you boil off H2O.

[martinmin]

"0 TDS", does that mean GH and KH are both 0? 

[Mmiller2001]

On 7/7/2024 at 9:52 PM, martinmin said:

"0 TDS", does that mean GH and KH are both 0? 

Yes, pure water.

[martinmin]

But zero GH would be problematic for many plants, right? I don't understand how it worked.

[Mmiller2001]

On 7/7/2024 at 11:57 PM, martinmin said:

But zero GH would be problematic for many plants, right? I don't understand how it worked.

Correct, if you use RO/DI the water is pure H2O and contains no GH and KH or any traces minerals. You add back those minerals to the desired amounts. The advantage is you now know exactly what’s in the water versus the tap water which has all kinds of “stuff” in it.

[martinmin]

On 7/8/2024 at 6:41 AM, Mmiller2001 said:

Correct, if you use RO/DI the water is pure H2O and contains no GH and KH or any traces minerals. You add back those minerals to the desired amounts. The advantage is you now know exactly what’s in the water versus the tap water which has all kinds of “stuff” in it.

If you have a big tanks, or a few tanks, then this way seems complicated, and high cost. Is that right?

[Mmiller2001]

On 7/8/2024 at 8:55 PM, martinmin said:

If you have a big tanks, or a few tanks, then this way seems complicated, and high cost. Is that right?

Cheaper than a bottle of Easy Green and last 10x longer. I’m thinking of starting a YouTube channel, and if I do, I should go through this process. It’s easy but intimidates many for some reason.

[martinmin]

On 7/8/2024 at 10:34 PM, Mmiller2001 said:

Cheaper than a bottle of Easy Green and last 10x longer. I’m thinking of starting a YouTube channel, and if I do, I should go through this process. It’s easy but intimidates many for some reason.

@Mmiller2001 it would be really great if you can do a YouTube video introduction, and if you do it, please update here it. I am eager to watch! It sounds great.

[Pepere]

On 7/9/2024 at 1:34 AM, Mmiller2001 said:

Cheaper than a bottle of Easy Green and last 10x longer. I’m thinking of starting a YouTube channel, and if I do, I should go through this process. It’s easy but intimidates many for some reason.

I am assuming the cost of fertilation is cheaper than Easy Green…. The RODI unit is certainly not cheaper than a bottle of Easy Green….

I am thankful I have very soft tap water 1 deg GH and KH…

[Mmiller2001]

On 7/9/2024 at 5:39 AM, Pepere said:

I am assuming the cost of fertilation is cheaper than Easy Green…. The RODI unit is certainly not cheaper than a bottle of Easy Green….

I am thankful I have very soft tap water 1 deg GH and KH…

Yes, the RO cost upfront is higher but cheap to maintain. 
 

That said, using the minerals to make my own fertilizer is significant. I can make roughly 25 bottles of fertilizer for the cost of one 500ml bottle of Easy Green.

[Pepere]

On 7/9/2024 at 8:24 AM, Mmiller2001 said:

Yes, the RO cost upfront is higher but cheap to maintain. 

Depending on how hard tap water is though waste water from rodi operation can certainly drive your water and sewer bill.

living in a soft water location has its benefits…. A local fish keeping friend has a drilled well.  His water comes out of the well at 5 degrees GH with a near perfect Ca/Mg ratio…I forget what his KH is, but it is soft and he doesnt supplement it. My tap water is surface water from Lake Auburn, it is much softer than what comes out of the tap as the water utility doses it to add a bit of GH, KH, and raises the PH a bit to prevent Lead from lead solder from leaching in to the water…

[gjcarew]

You can use hydrochloric acid to lower kh if you're willing to take the risk