My pond test strips I bought on Ebay finally arrived after waiting 19 days for Royal Snail Mail to deliver them, so I did a test. Most things are OK, (NO3=10, NO2=1, a bit high, KH=6d, ph=between 7.6 and8) but the GH is very high at 16d. The instructions with the test strips say to do a part water change using rainwater. As it is not very rainy at the moment, is there another, safe, way to lower the GH a bit?

Hard water is really not a problem. Use of rain water could be a problem,
since it has no KH and your KH is at what I would call a lower limit. If it
drops by 1/2, you could be in for a pH crash. If you have not been doing
partial water changes, removing water from the pond, rather than just
topping off, then evaporation of your mains water will increase the GH.
Check the mains water and see if there is a significant difference. If so,
it would indicate a significant water change is in order, if not, then don't
worry about it.
--
RichToyBox
http://www.geocities.com/richtoybox/pondintro.html

"billfish" wrote in message
...

My pond test strips I bought on Ebay finally arrived after waiting 19
days for Royal Snail Mail to deliver them, so I did a test. Most things
are OK, (NO3=10, NO2=1, a bit high, KH=6d, ph=between 7.6 and8) but the
GH is very high at 16d. The instructions with the test strips say to
do a part water change using rainwater. As it is not very rainy at the
moment, is there another, safe, way to lower the GH a bit?


--
billfish

[quote=RichToyBox]Hard water is really not a problem. [quote]

Sorry. When I typed in my post I didn't realise this forum doesn't support "more than" arrows. It should have read that the GH is more than 16, i.e. off the scale on the test strip and classed as very hard water. I was a bit concerned because, from what I've read, for most fish, including GF and Koi, moderate to fairly hard water is preferable. When you say the KH is at the low end, what should it ideally be? I live on an island, so seashells to put in the filter are not a problem for me if you think it is required to raise the KH.

Bill.

The filter bacteria consume KH, and if the KH drops to around 40 pH crashes
are imminent. For the bead filters, they really need KH values over 120 and
values to 300 are not detrimental. If the KH is constant, above 100, the pH
is pretty stable. As for the use of the sea shells, they are calcium
carbonate, and will only dissolve when the pH is pretty low. They do an
excellent job of preventing pH crashes, if there is sufficient quantity
available, but they also release calcium which makes the water harder.
Baking soda will raise the KH without raising the GH hardness. If you are
getting the high GH values due to the dissolution of sea shells, then more
frequent water changes would be in order.
--
RichToyBox
http://www.geocities.com/richtoybox/pondintro.html

"billfish" wrote in message
...

RichToyBox Wrote:
Hard water is really not a problem.

Sorry. When I typed in my post I didn't realise this forum doesn't
support "more than" arrows. It should have read that the GH is more
than 16, i.e. off the scale on the test strip and classed as very hard
water. I was a bit concerned because, from what I've read, for most
fish, including GF and Koi, moderate to fairly hard water is
preferable. When you say the KH is at the low end, what should it
ideally be? I live on an island, so seashells to put in the filter are
not a problem for me if you think it is required to raise the KH.

Bill.


--
billfish

The high GH is not due to sea shells as there are none in the pond at present. I'm not a geologist soI cant say what the exact makeup of the water catchment is here. I do know however that the majority of the rock which forms the island is granite and other very hard rocks of that type. There are no significant chalk deposits. We get incredibly hard limescale buildup in kettles etc, so the pond GH being high is not too surprising. Also the lack of limestone or chalk might explain the low KH value. I will try a test on the tap water as well as a re-test on the pond. If necessary I will do a part water change and add baking soda. By the way, is baking soda the same as sodium bicarbonate?

Baking soda is sodium bicarbonate, bicarbonate of soda, hydrogen sodium
carbonate, or acid sodium carbonate. All terms are for the same chemical.
--
RichToyBox
http://www.geocities.com/richtoybox/pondintro.html

"billfish" wrote in message
...

The high GH is not due to sea shells as there are none in the pond at
present. I'm not a geologist soI cant say what the exact makeup of the
water catchment is here. I do know however that the majority of the
rock which forms the island is granite and other very hard rocks of
that type. There are no significant chalk deposits. We get incredibly
hard limescale buildup in kettles etc, so the pond GH being high is not
too surprising. Also the lack of limestone or chalk might explain the
low KH value. I will try a test on the tap water as well as a re-test
on the pond. If necessary I will do a part water change and add baking
soda. By the way, is baking soda the same as sodium bicarbonate?

RichToyBox Wrote:

Baking soda will raise the KH without raising the GH hardness. If you
are
getting the high GH values due to the dissolution of sea shells, then
more
frequent water changes would be in order.
--
RichToyBox
http://tinyurl.com/6k2bp

"billfish" wrote in message
...-

RichToyBox Wrote:-
Hard water is really not a problem. -

Sorry. When I typed in my post I didn't realise this forum doesn't
support "more than" arrows. It should have read that the GH is more
than 16, i.e. off the scale on the test strip and classed as very
hard
water. I was a bit concerned because, from what I've read, for most
fish, including GF and Koi, moderate to fairly hard water is
preferable. When you say the KH is at the low end, what should it
ideally be? I live on an island, so seashells to put in the filter
are
not a problem for me if you think it is required to raise the KH.

Bill.--


--
billfish-


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billfish