This topic has come up several times in the past, however I cannot recall what I am experiencing in my ponds now.

My PH has always been in the mid to high sevens and in the lower eights after bicarbonate of soda was added and my carbonates around the 80 to 100 mark.

Lately I have noticed that my carbonates are 20 but the PH is in the lower eights and I am not comfortable adding bicarbonate of soda as this will raise the PH to dangerous levels. I could not understand the sudden change so I measured my source water (municipal) and it has a PH of 9.2.

So this explains the sudden change and with the 10 - 15% water changes twice a week explains the high PH, the question is, do I ignore the carbonates or do I ignore the PH? What would you do?

Get a Borehole

costa j wrote:

Get a Borehole

What! on a hill a couple of hundred meters above sea level? I wish.

Is your ph always this high ? I think you should move to JHB

Is your ph always this high ? I think you should move to JHB

Hi Colin

Are you and Ara next door neighbours?

Same municipal water supply maybe.

costa j wrote:

Is your ph always this high ? I think you should move to JHB

Costa my PH is always around 7.8 to 8.2 when I use Bicarbonate of soda on a regular basis to achieve a KH of 80 to 100.

coolwon wrote:

Hi Colin

Are you and Ara next door neighbours?

Same municipal water supply maybe.

I have no idea where he stays.

Colin,
Ek sal nie baie worry as ek jy is nie. Lees hieronder.....................

pH stands for potenz Hydrogen (a German expression meaning the activity of Hydrogen).
It must always be written pH even if it is a title or it is at the beginning of a sentence as above.
To write it as PH or Ph is incorrect as these two abbreviations mean something entirely different.

So, with the pedantic stuff out of the way, what is pH?
pH is a measure of the alkalinity or acidity of a substance.
It is the balance between free Hydrogen ions (H+) and free Hydroxyl ions (OH-).
Pond water that is exactly 7.0 is neither acid nor alkaline, it is neutral.
Water that is below 7.0 is acid, and above 7.0 it is alkaline.
pH is measured on a logarithmic scale which, in simple terms, means that each time you change by one on the pH scale, the acidity or alkalinity has changed by a factor of ten.
For example, if the pH of your pond falls by one on the pH scale from 8.5 to 7.5 it has become ten times more acidic.
Similarly if the pH falls by two from 8.5 to 6.5 it has become one hundred times more acidic.
In Koi keeping terms an abrupt fall in the pH such as this is known as a pH crash. Koi are happy if the pH of their pond water is anywhere in the range of 7.0 to 8.5 and are not too stressed if the water is between 6.5 and 9.0.
But the actual value must be stable because their blood pH is an essential part of the way that Carbon Dioxide is removed from their blood stream and Oxygen is taken up from the water to replace it. The pH of their blood rises when it is rich in Oxygen and falls as their body tissue uses this Oxygen and replaces it with Carbon Dioxide. Their blood chemistry will adjust to slowly changing values of pH but it cannot adjust quickly enough if the changes are too rapid. Even though Koi are healthy in the range of 7.0 to 8.5, they will become stressed if the value varies too quickly within this range.
The action of plants, and especially algae, will cause daily variations in pH.
During daylight hours, they remove Carbon Dioxide from the water and replace it with Oxygen. The removal of Carbon Dioxide causes the pH to rise.
During darkness, the photosynthesis of plants and algae reverses. They take up Oxygen and give out Carbon Dioxide into the water. Carbon Dioxide (CO2) in water (H2O) produces Carbonic Acid (H2CO3) which reduces the pH.

This is a natural process with which fish have evolved over millions of years.
In the morning the pH is lower than it is in the evening. Variations of 0.2 per day are acceptable, but larger variations should be regarded as too stressful for the Koi’s physiology to cope with.
If the pH was allowed to fall below 5.5 Koi will suffer from acidosis. They will exhibit the usual signs of discomfort, flicking, flashing and jumping.
The chemistry that allows the gills, firstly, to take up Oxygen from the water, and then to get rid of Carbon Dioxide and Ammonia, will be disrupted.
The fish will soon be gasping at the surface or near air stones, waterfalls etc. If the acid conditions are allowed to persist, the fish will attempt to reduce the irritation by producing excess mucous and it’s skin may become tinged with red. These acid conditions must be corrected or the fish may die, but the correction must not be done too quickly because rapid changes in pH are also harmful.
One way of increasing the pH is by adding Sodium Bicarbonate (NaHCO3) which is more commonly known as baking soda.
This has the advantage that it is non–toxic and will not increase the pH above 8.4 no matter how much is added. The suggested dose rate is 5g per 1000 lt water. This should be dissolved in pond water in a bucket and sprinkled around the whole of the pond. The pH should be checked before the treatment and again after a couple of hours to see if further adjustment is necessary. Only in severe cases should a second treatment be added on the same day. Otherwise it is best to increase the pH by about 0.2 per day.
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. They also tend to buffer the pH between 7.3-7.6
In a typical Koi pond the tendency will always be for the pH to fall, over time, due to the loss of the Hydroxyl ions that are removed by biological action, especially in the filters.
So slowly rising pH values are not common, but if the pH was allowed to rise above 9.0 the Koi will suffer from alkalosis and will exhibit the same symptoms.
Action to reduce the pH must be taken without delay, but again the rate of change must not be too rapid as this also can do more harm than good. A bag of peat placed in the filters is a gentle but effective way to lower the pH. Hydrochoric Acid (HCI, spirit of salts or pool acid) can be used, but it is a dangerous chemical and should be used with caution.
Since incorrect pH can cause the Koi to swim erratically and gasp at the surface, the obvious worst case situation is that the inexperienced Koi keeper may mistake these symptoms for a parasite problem and treat the pond with a medication.
Since many of these medications will reduce the amount of oxygen in the water, this treatment may actually be “the last straw” and, as such, the fish may not be able to survive. It is important, therefore, to ensure that all water parameters are checked and corrected before attempting any diagnosis or treatment.
The fish may not actually be sick, it may only be showing a reaction to poor water conditions.

Ek stel voor dat jy oester skulpe in jou sisteem plaas, wat sal help om die pH konstant te hou.

Thanks Pieter, it says everything, Brilliant article.

Hi Collin,
my PH was also very high and I have a borehole...source water is 8.5...plus the unsealed pond...I had ph 9 or more...(my test kit measures up to 9)...had it for a year...and had no problems that I could see...now it has normalized to 8.5 or around that.
I was advised not to tamper with my PH...reducing it...I was told that is when U can have a real PH crush...it is a difficult procedure...and dangerous one...People use special pump that measures PH and discharges liquid to adjust the PH slowly and constantly...
Pieter,
Thank U for the super dooper article...very informative!
Collin, dont add soda B...but U need to increase your KH...add oister shells as pieter said...crush them very small...they will act much faster than when large...and will be a long therm solution...

Thanks Pieter, that is a excellent article and I feel a bit more comfortable adding my bicarb now and will check to see if it does not exceed a pH of 8.5.

I must say the fish look very happy and show no signs of stress but one can not be careful enough.

Pieter,
quote:
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. They also tend to buffer the pH between 7.3-7.6
Do U mean PH or KH?

Colin let me throw a curved ball your way -

Why do you think you have a problem?

Do you have a problem because of the things you have been told and your test kit readings?

How are your koi? Healthy? Happy? Growing well? Good colour? Living a long time? If the answer to these questions is yes then I suggest your throw your test kits away. Then you won't have a problem any longer!

Just an observation - if your source water is very alkaline why are you adding bi-carb? Perhaps the high alkalinity in the source water is more than enough for your system already and your water quality may be more stable and better without any additives.

If you measure carbonates in the pond then you must measure carbonates in the water source. If you measure pH in the pond then this must be compared to pH in the water source. You can then compare apples with apples.

The less we fiddle with water quality parameters the better. Koi can and do adapt to a wide range of water quality parameters.

Chris

Chris, curve ball indeed! Your first and second question can be answered by the fact that there are SO many opinions in the Koi game that at times become confusing. Some people say watch your pH others will insist that your carbonates are more critical and not to worry about pH, hence my question "pH or Carbonates".

With my source water with a 9.02 pH and my pond water with a carbonate reading of 20 does not make me comfortable adding bicarbonate of soda to raise my carbonates to 80 - 100 as this will increase the pH, until I read Pieter's post, which I will obviously test, made me feel a bit more comfortable.

Your next question was if my source water is alkaline why add bi-carb? Is this the same thing? I have always understood that Alkalinity and Carbonates are two different things, as my readings in my pond at present is pH of 8.2 which has a very high alkalinity, however my carbonate reading is only 20. Is my understanding correct? and if not why?

My source water has a pH of 9.2 and carbonate reading of 30 compared to my pond of pH of 8.2 and carbonate reading of 20.

The fish all look very happy and grow extremely well and have good colour, however the 2010 saga still sticks in my mind with the sudden spikes I had that came from nowhere, I am extremely pedantic about any changes and things that do not add up, so please excuse the concern.

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.