let tank age naturally before buffering?

[sammigold]

Went to LFS today to buy shellgrit to raise kh. Was advised to let tank age naturally for a while so that the ph drops a little before adding shellgrit as ph is at between 7 and 7.2. Otherwise he said the shellgrit will cause the ph to raise too much and will stress the fish. Is this ok? Our ph is pretty constant. Our other tanks haven't experienced any major drops. We have grit in our "old" tank and the ph and kh have remained constant. At the moment our new tank has a kh of about 1. Everybody is happy and even plants are showing new shoots. The tank has had fish and plants in it for about 6 weeks. No nitrites. LFS said water perfect. Still no discus yet. Maybe this week or next. anyway the question is "is my LFS right should I wait before putting in shellgrit?"

[duck]

You have a PH of around 7.3 and a kh of 1.

[Benny]

why would you want to raise the hardness of your water out of curiousity?

Discus naturally prefer a softer acidic water?

Regards
benny

[sammigold]

Duck Hi. our ph is between 7 and 7.2 It is not 7.3 On checking the water this morning the kh is virtually zero.

Benny Hi. We want to raise the KH a little to prevent sudden drops in PH. We aren't trying to raise the GH. That is fine. Very soft in fact.

The thing is in our other tanks we have got a kh of about 3 and our Ph sits stable at just over neutral (7-7.2) but they have been around for years so we haven't had to worry about low kh for a very long time. Now that we are trying to set up for discus we want to make sure all is right before we put them in. Don't want to suffer huge fluctuations in ph after we have the little buggers. Want to prevent problems before we have to find solutions. Does that make sense?

[Sam]

kh is the buffering capacity for ph. u should had a kh of 3 to 4 dergrees for discus.
benny: if ur kh is low ur ph will not be stable and drop.

[Benny]

u could have told me that over msn sem sem :P

how kh works as the buffering capacity for pH does not make sense to me from a scientific perspective though... Coz kH is calcium hardness right? and how does calcium ions have any relation to hydroxide or hydronium ions in water? unless there is some equilibrium between calcium, calcium hydroxide and CaH present in which case Kh would make sense that it acts as a buffer

bah
this fish keeping has be baffled at times

[sammigold]

So..... do I wait or do I buffer now and risk raising ph?

[Merrilyn]

Do it now Sammi. The pH naturally drops within 48 hours of being drawn from the tap. With no buffering capacity in our water at the moment, once you add fish, there is a very real danger of a pH crash. It can drop two full points in around 24 hours, which is a lot more stressful to your fish than a slightly elevated, but stable pH.


Benny, try this link for a a bit more information on water chemistry.

http://user.aol.com/andrerich/aquari...e6.html#guide2

[Sam]

mate kh is karbonate hardness.

[Dee]

kh is carbonate hardenss.

Sammi, I agree with Merrilyn ... get the kh and ph where you want them for a week or so prior to adding fish. Once the fish are in the tank for a while with feeding and waste etc, depending on stocking levels, the ph will drop with unbuffered Melbourne water (with my Melbourne water it does anyway). I can't remember the site i got this info from but there was a info table that listed kh values and their respective ph values. From memory it went something like this ---

kh 1-2deg = ph 6.4 - 6.6
kh 3-4deg = 6.7 - 7.0
Kh 5 and up = 7.1 and up

although don't hold me to this info, as my memory aint what it us to be. :P

HTH

Cheers,

Dee