Gh And Kh

[michaelwgroves]

I am running a 900 litre planted community tank, please read my profile for more details.

I have been advised I need to ideally get my gH to 5.
I am slowly going down this road by introducing RO in my weekly water changes, it's currently 6, down from 7.
So this is going well.

However, I am unsure what kH I should be aiming for, and how to adjust, could someone advise?
I currently have a kH of 4

 

[Bignose]

Firstly, the abbreviations properly have both letters capitalized. GH and KH. pH is the one with the little p, big H.

But, more importantly, why do you think that you need to specifically lower the GH to 5 down from 7? Are you trying to breed? Are you trying to keep some rare wild caught fish? Are your fish acting ill?

If you aren't trying to do anything special, there really isn't any need to change these parameters. Fish are pretty adaptable really, and only need special conditions is they are going to be bred, or are exceptionally finicky.

Is this your current stocking?

11 Cardinal Tetra
5 Harliquin Tetra
5 Glowlight Tetra
11 Mollies
10 Platties
9 Guppies
6 Cherry Barbs
3 Clown Loaches
2 Yo-Yo Loaches
2 Opaline Gouramis
2 Red Male Dwaf Gouramis
2 Red Femal Dwaf Gouramis
1 Blue Male Dwaf Gouramis
1 Blue Femal Dwaf Gouramis
1 Silver Angel
2 Koi Angel
2 Fork Tail Rainbow
7 Rummie Nose Tetra
6 Corydoras
10 Otas
3 Bristlenose
4 Freshwater Shrimps
28 Amano Shrimps (Aparently!)
1 Male Siamese Fighter
5 Female Siamese Fighters
2 Black Knife Ghost Fish
4 Kuhli Loach

If the cardinals and the corydoras (depends on what species they are) seem healthy and happy, I think that everything else is pretty fine. A lot of cardinals are wild caught, so they aren't quite as adaptable as some of the bred fish. Same thing with the corys, if they are a rare wild-caught species, they may not adapt. But, if they seem healthy, everything else is relatively common and adaptable, you should be fine. I wouldn't change a thing.

 

[michaelwgroves]

My stocking list is fairly up-to-date, although I have also lost my Blackknife Ghost Fish and Male Fighter recently.

Fish are now all fairly healthy, I had not had any major loses since December when I got NTD, although I have recently lost about 20 fish which, I thought was NTD again as there were no signs of illness that I could spot, but all seems okay again. This basically started a week after buying fish from somewhere I had not tried before, needless to say, I wont be going back!

Basically I'm a bit of a perfectionist, if GH 5 is ideal, then that's what I want, for no other reason than that. And because I have an RO unit, it's no hassle.

Something I just thought of, my mix is 3:1. which amounts to 20 litres RO, 60 litres tap. Obviously I put dechlorinator in for the tap, but should I be putting additives in the RO?

Finally, what is the ideal for KH?

 

[Bignose]

Maybe you missed my point, but there isn't really an "ideal" GH unless there is a very specific goal. For example, some fish will not breed unless their water is/becomes much softer than it currently is -- this is like simulating a rainy season when the soft water rain fills up the streams and lakes and riverbeds.

But, if you are NOT planning on breeding, there is no ideal GH. If you were keeping a species only tank, you could shoot for the GH of the fish's natural waters, but you have fish from all different waters across the world. So simply put, if the fish are all healthy, then the GH where the water is at now is ideal.

There really is not such thing as a perfect GH. I know people who have all the same fish as you (not all in one tank as large as yours), keeping them in the hard water of the U.S.'s Midwest, GH's well over 20, and the fish are perfectly healthy.

The exact same things can be said about KH. Pretty much, the ideal KH is anything over about 3 or 4. If the KH gets too small, there is a chance the water will lose its buffering capabilities, and a pH crash will result. But, if you are doing regular water changes, the buffering of the water will be replenished, and it isn't really an issue. Again, there isn't a specific ideal value.

In both cases, the fish themselves will tell you what is ideal. If the fish are happy and healthy and showing good colors and growing and eating well and all the other things that indicate healthiness, then the water is fine.

 

[michaelwgroves]

Good explanation, the penny has finally dropped.

My tap water is about 7 GH and 4 KH, so as per your responce, no need to play around with it.

So there now appears to be no reason to use RO, or is there?

 

[Bignose]

I wouldn't think so. Just do all the regular maintenance, specifically the water changes, and you'll be fine.

 

[nmonks]

That's actually tending towards soft water. Fine for barbs and tetras, but less so for things like livebearers, goldfish and many cichlids. By default, I tend to see hard water as the best all-round situation. Soft water fish will generally adapt safely to hard water, but the reverse is very rarely true. 6-18 degrees dH and 5-10 degrees KH are, in my opinion, the optimal values for the community tank containing "a bit of everything".

Cheers, Neale

My tap water is about 7 GH and 4 KH, so as per your response, no need to play around with it.