GH, KH, pH: Ahh, Chemistry!

[pankelephant]

I picked up a GH/KH kit today. I'm planning a 55g and figured this would help narrow my stocking choices. While I know that most fish can adapt to varying degrees of hardness and pH, I'm a chemist so I wanted to know. With my background you'd think this was all fairly easy ... not so much. While I understand what all these things mean and how they work, I don't understand how it applies to the home aquarium.

My pH is 7.2 and has been very stable. My GH and KH are wicked low though - both are 2. That's with week-old tank water. Out of the tap the pH and the KH are the same; the GH is 1. (I'm on city water.)

The one I'm the most worried about is the KH because of the pH stability issues. I know that I can use all kinds of chemicals to adjust these levels - calcium carbonate, calcium chloride, sodium bicarbonate, magnesium sulfate ... the list goes on. What I don't like about these solutions is that I have to continue to add them over time. Failing to do so would drop the KH and possibly trigger a pH swing. This is bad.

So - what should I do? What do you do? Can I just ignore it, given that my pH has been stable from the beginning? Should I add something, and if so, what/how? Do I need to seriously consider this when choosing fish for the new tank? As in, no African cichlids? Or rainbows (which would be exceptionally disappointing)?

What say you?

 

[lovemyguppies]

You can add crushed coral into your filter to increase kh

 

[armymp327]

I picked up a GH/KH kit today. I'm planning a 55g and figured this would help narrow my stocking choices. While I know that most fish can adapt to varying degrees of hardness and pH, I'm a chemist so I wanted to know. With my background you'd think this was all fairly easy ... not so much. While I understand what all these things mean and how they work, I don't understand how it applies to the home aquarium.

My pH is 7.2 and has been very stable. My GH and KH are wicked low though - both are 2. That's with week-old tank water. Out of the tap the pH and the KH are the same; the GH is 1. (I'm on city water.)

The one I'm the most worried about is the KH because of the pH stability issues. I know that I can use all kinds of chemicals to adjust these levels - calcium carbonate, calcium chloride, sodium bicarbonate, magnesium sulfate ... the list goes on. What I don't like about these solutions is that I have to continue to add them over time. Failing to do so would drop the KH and possibly trigger a pH swing. This is bad.

So - what should I do? What do you do? Can I just ignore it, given that my pH has been stable from the beginning? Should I add something, and if so, what/how? Do I need to seriously consider this when choosing fish for the new tank? As in, no African cichlids? Or rainbows (which would be exceptionally disappointing)?

What say you?

if you want to keep african chichlids, then crushed coral as suggested above would be your best, and safest bet. it will raise your KH and PH, however you will need to be careful when doing water changes, because the crushed coral effect is not immediate.

ive never used it myself but i know thats what it does, hopefully someone who has more experience can explain how they do water changes to not cause the KH and PH to swing.

 

[pankelephant]

I was hoping to find a way to keep the pH where it is. I don't think A. cichlids are in my immediate future, but I'm trying to prepare for all eventualities. Before anything else though, I need to know how important it is to change the numbers in the first place.

 

[marsh]

Following thread. I ask myself this type of stuff often

 

[spiketooth]

Thats going to be hard to do it natural, i have the same issue, well not really a issue. My kh out of the tap is 3 and ph is around 7.5. In my 40 gal tank without co2 my ph is 8. My kh is around 8, but thats becuase my substract is sand coral or coral sand how ever you want to say it so it brings it up. I do a 25% water change weekly with not issue. I have been raising guppy frys in this tank(about 50 of them). With co2 i keep my ph at 7.4. I had no deaths with this tank.

 

[BBradbury]

Water Chemistry

Hello pank...

I was told several years ago when I got into the hobby, that unless your aim was to keep and breed rare fish species, you didn't need to fret over the pH, hardness, or any of that kind of thing. I was told it wasn't important and not to get creative and try to change anything. So, far the advice was correct.

It was my understanding that most aquarium fish could easily adapt to most municipal water supplies. The only thing that had to be done to the tap water was to remove the chemicals the city people put into it to make it safe to drink. So, I've always treated the new water with a chlorine and chloramine remover.

I've kept Guppies, shrimp, Tetras and Corydoras and none have had a problem with my treated tap water.

B

 

[aqua_chem]

Are you on a water softener by chance?

 

[pankelephant]

Thanks all, I'm beginning to feel much better about this. It seems that leaving it alone is the best bet for me. If I start to see pH swings, I think I'll add crushed coral. I'll have quite a bit of driftwood in my tank, so hopefully that will balance things.

@aqua_chem - I'm starting to think that's a possibility. I live in a condo in an old converted mill building. It's possible that there's a softening system in place. I have been told that our city water is usually very hard, so I'm going to look into that a bit more.

 

[aqua_chem]

I've heard the same of Boston's water, so your soft water surprised me.