What happened in 2010 Col, can't remember.

Neli,
I refer to pH.

Colin,
Please read this article, which I have posted on another forum in April 2009 to follow the above posted article.

"The TDS meter will read everything that is dissolved into the water in parts per million. That will include carbonates, bicarbonates, calcium and magnesium ( tested with KH a GH test kits) along with other metals and mineral content including manganese, copper, salts, organic carbons etc.
In short every thing that was once solid and is now dissolved.
Nobody can hide from the TDS meter.
TDS readings of over 800 ppm would indicate a level of pollution that’s indicative of any and all of the following:
little or no water changes,
dirty filters,
heavy feeding,
abnormal use of clays,
salt,
bicarbonate of soda,
or even chemicals,
Everything that can be dissolved in water, is what you looking at with this parameter.

Where a reading of 200 ppm or less would indicate a good partial water changes and near-perfect feeding, you could not achieve a recording of 200 ppm or less without having good water management. It’s so easy to run high TDS levels.
Koi will swim in what is, in effect, a thick viscous soup! They can certainly live in such water, but will not thrive.
Some Koi keepers think that some water top-ups are the same as doing a partial water change. (This is where you lose an amount of water by evaporation, and then top-up)

For example:
Fill a jug and fill it with 500ml of tap water and measure the TDS; reading around 240 ppm.

Now let half of the water evaporate, your TDS level now is at 480 ppm because only the water has evaporated, and not any solids you are now about to top-up with water containing 240 ppm.
So if you added 250 ml at 240 ppm your water will now be 360 ppm TDS. As you only adding 250 ppm and not 500 ml, the TDS will dilute out to 120 ppm when filling up to 500 ml.
Every time you ad water to top-up the TDS will increase.

If we take my tap water again ( TDS 240 ppm), it runs a GH of approx. 10 dh or 178 ppm and a KH of approx. 4dh or 70 ppm ( 70 + 178 = 248 ppm TDS) You will see that it more or less works out.
My ponds run at TDS of between 140-160 ppm with pH of 7.2, but I mix tap water with borehole water. The tap water is still the same at a pH of 8.4 and TDS of 240 ppm, but the borehole water records between 40-80 ppm with pH 5.

You can achieve this by running reverse osmosis water mixed with tap water

I do not recommend this to the hobbyist that have no time to monitor their parameters."

As dam een se TDS 400 ppm is sonder enige sout en dam twee se TDS 400 ppm is as gevolg van die sout inhoud; wat ongeveer 2kg/1000lt sout is; sal dam een meer oplosbare stowe bevat as dam twee, en sal dam een dus meer skadelik vir Koi wees.

KH of Karbonaat hardheid word gemeet asgevolg van die kalsium en magnesium soute wat in die water teenwoordig is; gewoonlik as die water "alkline" is. KH waardes oor die algemeen sal wissel tussen 8 en 12 *dH. Die Japanese glo dat die KH waardes tussen 1 en 4 dH die beste vir Koi is. Hier by ons waar die Koi damme meer na die "alkaline" kant toe neig is die KH waarde tussen 4 en 8 dH en is die water harder as in Japan.

GH (Algemene hardheid) of "degrees of German hardness" *d GH (dH) word water soos volg verdeel:
0-4*dH = Baie sag
4-8*dH = Sag
8-12 dH = Medium Hard
12-25* dH= Hard
> 25*dH = Baie hard

Koi gebruik meer energie om hulle sout/water balans te handhaaf in sagte water.
Japense verkies GH waardes van 1-3* dH, maar hulle grond damme bevat amper geen minirale nie.

Hoop dit help.

Hi Pieter,
U said:
Items like crushed oyster, scallop and abalone shells tend to be a much better long term solution for raising low pH and preventing acid-creep
As far as I know oyster shells are put to raise the KH and prevent PH crush....that is why I asked if U mean KH..
Do They raise the PH too and do U put them to raise the PH or to stabilize it.?

Neli.

As you know the pH of Sodium Bicarbonate (NaHCO3) is 8.4 which is the ideal reading for keeping Koi.
If the pH reading reaches 8.4, it will stay there even if more Sodium Bicarbonate was added to the pond water. Oyster, Scallop and Abalone shells manage to do the same but over a longer time and therefor it will raise the pH but will stabilize the pH over a longer period as well, preventing a sudden pH crush.
As the shells dissolve into the pond water the KH reading will be higher as more calcium enters the pond water.

Thanks Pieter...

What is wrong with using mussel shells? We have loads of mussel shells and are a lot easier to obtain than any other shell.

Colin,

Ek het nog altyd net Oester Skulp gebruik, weet nie of Mossel skulpe sal werk nie.
Dit hang maar seker van die Kalsium inhou af en hoe en indien enige deur die Mossel skulp vrygestel word.