Hardness

[Paulochromis]

I'd like to slowly move the water parameters in my Malawi tank towards those found in the lake.

At present, I do a 90-100L water change once a week. The volume of the tank is ~210L. I normally add a couple of teaspoons each of Seachem Lake Salt and Malawi/Victoria buffer during the change (as well as plenty of Prime).

Typical before/after readings:

pH: ...7.4 ..7.8

NH3: ... 0 ... 0

NO2: ... 0 ... 0

NO3: ...60 ...30

GH: ....10 ... 7dH

KH: .... 2 ... 2dH

I recognize that being lazy with cleaning the external canister probably contributes both to the high-ish nitrates and hence the low-ish pH.

What worries me is the low KH. I hear talk (well read posts actually) regarding the buffering capacity of the tank and how this is related to the KH.

I find the discrepancy between the GH and KH surprising. I guess I have plenty of Ca++/Mg++, but not enough of either CO3-- or HC03-.

What should I do? Add sodium bicarbonate? ANy clues on how to make the changes slowly (or at least provide some prtection against big pH shifts)?

Cheers,

[GTR73]

Lots of useful info here:

DIY salts

[Tam]

must be some expensive fish you got in that tank.

i always think we should try to adjust them to our local tap waters, much simpler and less complicated.

here is another link for you

http://www.thekrib.com/ (might help)

and yes you could use baking soda (carefully) or put some coral to counter adjust the hardness.

Tam

[Harry Morant]

What substrate are you using - coral sand will certainly help with raising the hardness but given that you're doing almost a 50% water change per week I think you might be pushing it uphill. You may wish to focus on improving the filtration so you can lower the percentage of the water change each week to allow the hardness to increase whilst lowering the nitrates.

[anchar]

Try this article for some information. Also note that high nitrates lower hardness.

Andrea