KH and GH - chemistry advice please 👩‍🔬

CPDtank96 · Oct 16, 2021

SO there have been a couple threads on here that I’ve found really interesting about water chemistry (I thinks that’s how you would refer to it) such as KH, GH, ph and water sources. I feel I was originally misled by my LPS (classic) as he said “all my fish are in the same water as you have so they will be absolutely fine and they’ve been bred in this water blah blah blah) obviously I know now this is not entirely accurate after reading material and threads posted here - thank god I know this now! Obviously a fish that thrives in acidic and soft water isn’t gonna be the one for me and ideally you should select fish that like water the same as your own source. Going forward I’ll be choosing fish that will thrive in my water parameters - problem is I don’t know what those are aside from my ph !

My question is though - I want to test my GH and my KH so I have an idea of the values - which test kit would be recommended for this?

Also, after a recent thread I’m unhappy giving my fish water from my tap if I can avoid this so I wanted to know what water sources people use if they don’t use tap water? I have a LPS where I can get RO water, I’ve seen some people use bottled water - just wanted some ideas really for alternatives !

Very interesting topic though so if anyone has any good sites they can recommend for more info please link them!

I read this one linked by one of the TFF members and it was very useful!

Understanding water hardness

Water hardness — not the most exciting of subjects to try and fully understand. The extensive amount of terminology makes the subject seem endless and confusing in equal measure.

www.practicalfishkeeping.co.uk

Bruce Leyland-Jones · Oct 16, 2021

Okay...so first slow down and visit your water suppliers website. Somewhere, buried within, will be all the water parameters you need to know, including hardness and such like.
For further testing, you need to keep an eye out for ammonia, nitrite and nitrate levels, especially if you're cycling a tank, but also if you need to eliminate possible causes of fishy distress.
The API Master Freshwater Test Kit gets good reviews and does what it says on the box, allowing you to keep an eye on your tank's water quality.

As you've gathered, your LPS talks shoemakers. They'll have all of their fish on the one system and their fish will be surviving, hopefully for as long as it takes for them to get sold.
NOTE that 'survive' does not mean 'thrive'...that's where you come in.

The fish themselves do have rather specific needs, relating to their water quality and this is determined by their genetics. These needs may have a little more flexibility in them than those of wild-caught fish, but they are still there and need to be acknowledged.

You'll probably find your tapwater is more than just good enough, but the trick is to match the fish you get to the water you get...if you have hard water, then you need hard water fish, soft water means soft water fish. There's plenty to choose from.
Once you start messing with your water, to accommodate certain fish, then you're setting yourself on a long and arduous path of pain, because it means that every single time you add water to the tank, you're going to have to tinker with it.
RO water is one of those relatively modern trends that some enthuse about and it is the only viable option in a minority of situations. I'd suggest you leave such paraphenalia until you're actually comfortable with the basics of fishkeeping.

FishHobby99 · Oct 16, 2021

CPDtank96 said:
SO there have been a couple threads on here that I’ve found really interesting about water chemistry (I thinks that’s how you would refer to it) such as KH, GH, ph and water sources. I feel I was originally misled by my LPS (classic) as he said “all my fish are in the same water as you have so they will be absolutely fine and they’ve been bred in this water blah blah blah) obviously I know now this is not entirely accurate after reading material and threads posted here - thank god I know this now! Obviously a fish that thrives in acidic and soft water isn’t gonna be the one for me and ideally you should select fish that like water the same as your own source. Going forward I’ll be choosing fish that will thrive in my water parameters - problem is I don’t know what those are aside from my ph !

My question is though - I want to test my GH and my KH so I have an idea of the values - which test kit would be recommended for this?

Also, after a recent thread I’m unhappy giving my fish water from my tap if I can avoid this so I wanted to know what water sources people use if they don’t use tap water? I have a LPS where I can get RO water, I’ve seen some people use bottled water - just wanted some ideas really for alternatives !

Very interesting topic though so if anyone has any good sites they can recommend for more info please link them!

I read this one linked by one of the TFF members and it was very useful!

Understanding water hardness

Water hardness — not the most exciting of subjects to try and fully understand. The extensive amount of terminology makes the subject seem endless and confusing in equal measure.

www.practicalfishkeeping.co.uk

I use the API kit

Essjay · Oct 16, 2021

@CPDtank96 Some water companies like to make things difficult to find. Your hardness might be under 'water quality' or like mine under 'in your area'. If you can't find it, tell us the name of the company and we'll see if we can find the page for you.
If you do find it, ignore the words, they can be misleading. You need a number and the unit of measurement. There are about 6 of those for hardness (it's a lot worse than litres, Imperial gallon and US gallons!) and fish profiles use only two so your number might need converting.
That will give your GH. Very few UK water companies give KH, and where they do they call it alkalinity. But this is not nearly as important as GH.

Byron · Oct 16, 2021

Agree with above posts here.

If you are on a municipal water system (and not a private well), chances are the water is safe to use as far as the water itself is concerned because there is legislation governing municipal water. The GH will be "x" and the pH which is directly related will by "y" and the KH will be something, and you should be able to ascertain these numbers from the water authority without buying tests [though a pH test is well worth having in general]. Provided you acquire fish suited to these parameters, you should be fine using the tap water. Chlorine (or chloramine) are probably being added, and these are dealt with via conditioners. The level of minerals other than the calcium and magnesium (which primarily determine GH, and contribute to KH and pH) is likely to be safe--though sometimes heavy metals like copper can be at higher levels for humans than fish will tolerate, but most conditioners also deal with this. In other words, the water from the tap, with a conditioner added, is going to be safe for fish suited to the GH/pH. So there should be no reason to avoid using the tap water.

Myraan · Oct 16, 2021

Afaik geographically most water in the uk is soft with the exception of the south east, ofc it's best to check to make sure.

CPDtank96 · Oct 16, 2021

Agree with above posts here.

Byron said:
If you are on a municipal water system (and not a private well), chances are the water is safe to use as far as the water itself is concerned because there is legislation governing municipal water. The GH will be "x" and the pH which is directly related will by "y" and the KH will be something, and you should be able to ascertain these numbers from the water authority without buying tests [though a pH test is well worth having in general]. Provided you acquire fish suited to these parameters, you should be fine using the tap water. Chlorine (or chloramine) are probably being added, and these are dealt with via conditioners. The level of minerals other than the calcium and magnesium (which primarily determine GH, and contribute to KH and pH) is likely to be safe--though sometimes heavy metals like copper can be at higher levels for humans than fish will tolerate, but most conditioners also deal with this. In other words, the water from the tap, with a conditioner added, is going to be safe for fish suited to the GH/pH. So there should be no reason to avoid using the tap water.

Thanks so much everyone great advice

Bruce Leyland-Jones said:
Okay...so first slow down and visit your water suppliers website. Somewhere, buried within, will be all the water parameters you need to know, including hardness and such like.

Okay amazing thank you! I’ll check out my water supplier for the information hopefully can find it easily there and will save me getting another test to check my water hardness that will be more accurate anyway hopefully

Bruce Leyland-Jones said:
The API Master Freshwater Test Kit gets good reviews and does what it says on the box, allowing you to keep an eye on your tank's water quality.

Amazing that’s the one I have and use so I’m glad I’ve got one that is decent !

Bruce Leyland-Jones said:
You'll probably find your tapwater is more than just good enough, but the trick is to match the fish you get to the water you get...if you have hard water, then you need hard water fish, soft water means soft water fish. There's plenty to choose from.

Perfect this was my plan as don’t want to be messing with water - I’m no chemist

Bruce Leyland-Jones said:
RO water is one of those relatively modern trends that some enthuse about and it is the only viable option in a minority of situations. I'd suggest you leave such paraphenalia until you're actually comfortable with the basics of fishkeeping.

1000000% agree with this and definitely was not my plan! I just want to know what water I have and then what fish will do best in it - I certainly will not be blindly listening to the advice of my LFS that’s for sure!!!!!!! I will probably have a look on seriously fish once I have acquired the information from the water board - is that a trustworthy website???

@CPDtank96 Some water companies like to make things difficult to find. Your hardness might be under 'water quality' or like mine under 'in your area'. If you can't find it, tell us the name of the company and we'll see if we can find the page for you
Oh lord let’s hope it’s easy to find but thank you so much will post in this thread if I struggle (I probably will

)

Byron said:
The GH will be "x" and the pH which is directly related will by "y" and the KH will be something, and you should be able to ascertain these numbers from the water authority without buying tests

Thank you for the heads up ! I read in that article you linked (very helpful so thanks for that!) that ph is linked to the hardness of the water something to do with kh and the carbonates being like sponges and absorbing the H+ ions right and acting as a buffer? Very interesting I must say ! This is what is upsetting about the hobby as there are lives involved and a lot of background science so why do pet shops just sell you whatever it’s very annoying -.-
though sometimes heavy metals like copper can be at higher levels for humans than fish will tolerate, but most conditioners also deal with this
I am concerned about the metals!!!! Glad the conditioner removes these thank goodness - I also read you have to be very careful with the dosage as if you just eyeball it it can change water parameters!!!!!!

Bruce Leyland-Jones · Oct 16, 2021

CPDtank96 said:
I will probably have a look on seriously fish once I have acquired the information from the water board - is that a trustworthy website???

It's far from perfect, but it's a great start.

StevenF · Oct 17, 2021

The API GH and KH test kit is a good one to have.

As to RO water I use it in my tank. I would not recommend buying it. Instead I would get a RO unit installed in your home or use a portable RO system. Many common RO system sold in hardware stores make only about 20 gallons of RO water per day. Which means these small unit are only good for small tanks. But larger systems are available.

For RO systems not need to use a GH booster to add some GH to your water. plants and animals generally need Calcium and magnesium for growth and good health. If you want plants in your tank you will also need to fertilizer the water. Unfortunately most fertilizers on the market depend on tap water supplying some of the nutrients plants need. So in my RO aquarium with an inert gravel supstrtate the 4 fertilizers I tried didn't work at all. I had to make my own micro and macro fertilizer to get good resultsSome people have had success with soil substrates but the substrates will eventulallly run out of nutrients requiring occasional substate change.

My recommendation it so mix RO water with tap water if your goal is to reduce water hardness. In most cases people use RO water due to harness issues. But if you have to use RO water use a GH booster , Use GLA DTPA EDTA micro fertilizer ( the only one on the market I know will work in my tank and add Potassium nitrate and phosphate fertilizers as necessary to get your plants to grow. The GLA website also has helpful dosing guidelines Also put a decorative sea shell in the aquarium. When the water gets acidic the shell will dissolve and cancel out the acidity keeping the PH very close to 7. You may need to replace the shell about once a year or so. This should work with an inert substrate (gravel, sand),and RO water. Do not worry or try to adjust the KH of your water.

CPDtank96 · Oct 18, 2021

StevenF said:
The API GH and KH test kit is a good one to have.

As to RO water I use it in my tank. I would not recommend buying it. Instead I would get a RO unit installed in your home or use a portable RO system. Many common RO system sold in hardware stores make only about 20 gallons of RO water per day. Which means these small unit are only good for small tanks. But larger systems are available.

For RO systems not need to use a GH booster to add some GH to your water. plants and animals generally need Calcium and magnesium for growth and good health. If you want plants in your tank you will also need to fertilizer the water. Unfortunately most fertilizers on the market depend on tap water supplying some of the nutrients plants need. So in my RO aquarium with an inert gravel supstrtate the 4 fertilizers I tried didn't work at all. I had to make my own micro and macro fertilizer to get good resultsSome people have had success with soil substrates but the substrates will eventulallly run out of nutrients requiring occasional substate change.

My recommendation it so mix RO water with tap water if your goal is to reduce water hardness. In most cases people use RO water due to harness issues. But if you have to use RO water use a GH booster , Use GLA DTPA EDTA micro fertilizer ( the only one on the market I know will work in my tank and add Potassium nitrate and phosphate fertilizers as necessary to get your plants to grow. The GLA website also has helpful dosing guidelines Also put a decorative sea shell in the aquarium. When the water gets acidic the shell will dissolve and cancel out the acidity keeping the PH very close to 7. You may need to replace the shell about once a year or so. This should work with an inert substrate (gravel, sand),and RO water. Do not worry or try to adjust the KH of your water.

Thank you so much for your help!

Not sure if I have read the information from my water board wrong but from what I can tell my water is unsuitable for all live stock and now I’m seriously concerned as I have fish in it!!!!! The value looks off the chart for hardness! I have attached images - I was hoping my hardness would be somewhere in the 250-300 ppm range using the conversion chart I found it’s looking like 400ppm am I reading this right?!

After seeing what’s in the tap water in my area I certainly will no longer be drinking it it’s disgusting!!!! There are even traces of arsenic, lead and cyanide in it

What should I do?

any advice would be great as I’m really concerned about my fish long term - they all look very healthy and are acting naturally with great colours but how long for if the water is this hard ! it’s way outside their parameters (and the parameters of any fish it looks like!)

Essjay · Oct 18, 2021

German hardness = dH and is 21.78. And it converts to 390 ppm, as you say just about 400.

Depending on the size of your tank, the common livebearers, most rainbowfish and Rift Lake cichlids would be OK in this hardness.

With that hardness, if you want soft water fish you would need to use something like 1 part tap and 3 parts RO, which would reduce your hardness to ~100 ppm. Or 100% RO and add remineralising salts.

CPDtank96 · Oct 18, 2021

I

Essjay said:
German hardness = dH and is 21.78. And it converts to 390 ppm, as you say just about 400.

Depending on the size of your tank, the common livebearers, most rainbowfish and Rift Lake cichlids would be OK in this hardness.

With that hardness, if you want soft water fish you would need to use something like 1 part tap and 3 parts RO, which would reduce your hardness to ~100 ppm. Or 100% RO and add remineralising salts.

I don’t think I would want anything living in that water the hardness is just ridiculous!!! Imagine if I was topping off with tap water as well it would be basically liquid rock!! Like you said they would be ok but it’s still even too hard for them isn’t it!

Okay thank you for your advice - really disappointed that my tap water is that hard as would have preferred to just select fish who are suitable for it but I haven’t seen 400ppm on any websites

Are there any good articles on RO I could read so I can get a better understanding of it that you’d recommend?? I could buy it from the pet shop in the interim but cost wise would be better for me to make my own I think in the long run

Bruce Leyland-Jones · Oct 18, 2021

CPDtank96 said:
I

I don’t think I would want anything living in that water the hardness is just ridiculous!!! Imagine if I was topping off with tap water as well it would be basically liquid rock!! Like you said they would be ok but it’s still even too hard for them isn’t it!

Okay thank you for your advice - really disappointed that my tap water is that hard as would have preferred to just select fish who are suitable for it but I haven’t seen 400ppm on any websites

Are there any good articles on RO I could read so I can get a better understanding of it that you’d recommend?? I could buy it from the pet shop in the interim but cost wise would be better for me to make my own I think in the long run

Another option could be Still bottled water.

CPDtank96 · Oct 18, 2021

Bruce Leyland-Jones said:
Another option could be Still bottled water.

Thanks so much for the advice

Am I right in thinking still bottled water still has dissolved minerals in it but just a lot less than my tap water? Do you still have to treat the water from a bottle or is it untreated because it isn’t tap water?

Thanks again for your help

Deleted member 149562 · Oct 18, 2021

I use bottled water in all 5 of my aquariums due to horrible tapwater

No treating required such as dechlorination....straight out the bottle.

Just make sure that the pH is the same....I use Highland Spring, Evian, Volvic and Buxton...not mixed in each aquarium but from the start used the one brand per aquarium

No hassles whatsoever with fish health or welfare, good growth, no issues with chemistry etc

Buy in bulk as its cheaper....currently my supplier is Asda.

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KH and GH - chemistry advice please 👩‍🔬

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