Melbourne KH (Carbonate Hardness)

[Dee]

Hi All,

I'm in Melbourne and have been having problems keeping my ph stable, it keeps falling rapidly. I did some tests tonight on my tap water using Aquarium Pharmaceuticals KH and PH test kits. The results where ---

KH = dKH 1 degree or approx 20ppm
PH = 7

The very low KH reading explains the fall in PH in my tank. My tank was at about 6.4ish last night after a 30% WC, then fell to 6 by the time i got home from work tonight. :shock: My questions are ....

1. What is a good KH value to buffer my PH and for general discus keeping, not for spawning.

2. Is the KH value relative to PH value ... ie - if I raise my KH does my PH rise too ? If so, will I have to raise KH slowly so I dont stress the fish with a PH swing upwards? Although the current PH swing downwards wouldn't be doing them any good.


3. Should I add KH powder to my water storage before adding to tank to get desired results? Doing 30% WC slowly with KH adjusted water.


OR

4. Should I add shell grit to the tank and do it that way ? How long does it take for shell grit to start working and raise the KH? I assume adding it to my storage tank wont do much in 24 or so hours?

5. Are there any other factors that may be lowering my Ph quickly? I keep my BB tank pretty clean with 30% daily WC's, feed 4 times a day and only have a small peice of drift wood in the tank. Its a 4x2x2 tank with 13 juvi's with a 2217 Eheim and a 2215 Eheim canister filters.

Sorry for all the questions :roll: I just want to get my PH stable. Any advice would be most appreciated. :)

Cheers,

Dee :)

[pitchblack]

I find the water from melb has a very low kh value as well. Since my tank is planted I do add ph/kh buffer so get my kh to 100ppm for the plants. Ive found by doing this Ive kept the ph constant at 7.0 with no problems at all. But constant ph change is not good for discus.

[Merrilyn]

There is an excellent article here on water and the buffering agents that can be used. You will note that they recommend crushed oyster shell, or shell grit to prevent pH swings in soft water.

http://www.fishdoc.co.uk/water/waterhome.htm

Some of it is pretty heavy reading, but it gives very thorough explanations.

[flukes]

Great link, thanks for the read...

[Trebs]

Kh of between 4-6 should keep your ph at around 7.2. This will vary a little depending on your fish load.

[Dee]

Hi Merrilyn,

Thank you very much for the link, very informative and a very interesting read. The articles I read pretty much well answered most of my questions, so thank you for taking the time to post that link. :)

Trebs,

Thank you for the info. It looks like I will be aiming for around 4degrees KH. I will be raising my KH VERY slowly over the next 2 weeks or so. Are there any pointers I should keep in mind when raising KH which will inturn raise my PH. My PH currently sits at around 6.4ish which I will raise slowly via raising the KH to around 7ish.

Once again thanks to all for the info, most appreciated.

Cheers,

Dee :)