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Ok, I've recently started shaping up my tank after a year of neglect.

Tested my gh/kh tonight and concerned with the gh level as I have SA cichlids (domestic bred but still concerned & if I ever get eggs..)

I then tested the gh & kh of the aged water I use for water changes for comparison.

40g water analysis - Dec 7,2007.
Ph 7.5
Gh 16 degrees = 286.4 ppm
Kh 6 degrees = 107.4 ppm

Aged Tapwater
Gh 8 degrees = 143.2 ppm
Kh 5 degrees = 89.5 ppm

That is QUITE the difference.

I'm guessing this is due to only topping up the tank for an extended period of time allowing calcium and magnesium to build up ?

Until Nov 24 I only topped up the water.
Between Nov 24 and Dec 3 I changed 22.5g of water.

There were some mts shells that may have leached calcium but the majority of visible ones have been removed. Flourite is the gravel. Only a teaspoon of Mono Potassium Phosphate has been added recently for the plants, half cap of liquid fert and Flourish Excel.

Should I do 10g water changes every other day or with 2 days in between until 30g has been changed then re-test ?

Also from the stats what is the co2 level ?

Thanks in advance for any help

The Amazon Nut...

I would change the water every other day, because that might be the only reasonable and easy way to remove the high hardness marks. You only changed like 50%, so you still have another 50% to replace before you get back on track! Just do it over time i guess.....

I dont know how to get Co2 levels......sorry!

><> ~=!Vote Today!=~ <><
-----> View My Dragons <-----

Hi MossMan

Using the calculator on this site gives a result of approx 5.7ppm CO2 in your 40g.

If it's definitely not your substrate or ornaments increasing the hardness of the tank water then I would have to assume that the MTS shells that have been breaking down in there combined with your previous routine of just topping up that is contributing to it.

As with any major changes in a tank with live inhabitants, try and do it slow and gradual (even if you are improving things) to reduce the shock on them.

G_T



Never be afraid to try something new. Remember that a lone amateur built the Ark. A large group of professionals built the Titanic.

I wouldn't trust that CO2 calculation. It specifically says on the site that if the water has a high phosphate level, the calculations won't work. Since KH2PO4 is being added, I think it's a safe bet that the phosphates are a bit above normal. Can you give us a level on that?

In fact, every kind of CO2 test kit I've looked at will give inaccurate readings in the presence of other buffering compounds. Hopefully FRANK or a plant geek knows a good way to do it.

It won't be the Flourite, according to the makers of the stuff. I have extraordinarily soft water and a Flourite substrate and neither my Gh hasn't budged at all.

I vote! Do you?

Hi,
I'd liked to have seen another value, the nitrate, back
before you started all the water changes.

The only thing that Flourite really adds is iron for the
plants. Its a clay, and does contain Magnesium (Mg) and
Aluminum (Al) but no calcium or carbonates that would
alter your GH or KH readings.

If you only topped off the tank for evaporation and did
no real house cleaning (gravel vacuuming) then the nitrate
reading would have been really high, and despite the
water changes, it will continue to be high. In a well
planted tank, you should strive to maintain the nitrate
readings around 10 +/- one or two. So if no gravel vacuuming,
I'd suggest you mentally divide the tank into four sections
and with each weekly water change, you clean a different
section. That way, in a month the entire tank has been
cleaned.

Check with your water supplier before drawing any radical
conclusions. Unless you are on a well, Cities will change
their sources at regular intervals. These changes involve
switching wells in different aquifers, drawing from
different bodies of water, or drawing from different levels
within a given body of water. All of these can give the
readings that you have mentioned (GH-8, KH-5).

Actually, water that has a KH of 5 and a GH of 8 is
perfectly fine for tetras and even for breeding them.
Its only the "wild caught" ones that will balk at breeding.
Nearly all of our tetras these days are farm reared in
water that is much like yours, and generations removed from
the soft acidic waters that most of the books talk about.
These fish do not require that the water have a pH in the
6s and a GH/KH readings in the 0-3 range.

If you want to lower your pH with your water GH/KH values
you might think about substituting RO or distilled water
for SOME of the tap water used in the water changes.
If you draw a gallon of water from the tap and let it
degas for a 24 hour period and then test it for the pH,
GH, KH values and then drain off a third or quarter or
half of it, and replace it with Distilled or RO water,
shake it up and let it degas then test again, you will
over a series of these, get a ratio so that you would
know that if you change out 5 or 10 gallons of tank
water then to maintain a given pH you need to add x nr
of tap water gallons, and y number of RO/DI gallons to
replace it.
(Written by THE Current FP Champion run-on sentence writer!)

Frank


-->>> The Confidence of Amateurs, is the Envy of Professionals <<<--

Thanks for the help all, and the extra detail Frank
(yes, you're the champion)

The nitrates would have been really bad before the wc's.
First water change coming this afternoon.

The Amazon Nut...

2 water changes down, 2 to go.

The Amazon Nut...