Do many of you still use Oyster shells within your filtration setup? Oyster Shells have been used for many many years by Koi Professionals here and in Japan in order to maintain a balanced PH level in the ponds water.

This of course helping to keep the water quality at it's very best.

With more and more looking at RO is the day of the Oyster doomed

Graham

Hi Graham,

I think Koi keeping has moved on a fair bit the last few years and with new types of filtration and ways to keep our fish that some of the "old style" systems and ways have changed somewhat. Of course that does not mean that they still cant be used or will not perform but its just we have become much more aware of what the fish need and how to look after them now.

Hi Graham
Call us oldfashioned but weve always used Crushed Oyster Shell and always will (don't change what Aint Broke My Friend).
rgrds
broxandval

Wary of going off topic here but... having woken up from a 'koi sleep' of 10+ years the changes in water management aren't actually that different. Before sleep... 1/3 surface area filtration to pond... turnover every 2 hours... as much aereation as you could get in there... aspire to add heat... water changes 10-20% per week... monitor parameters... AFTER SLEEP... technology has been the biggest change I see... the black box/multi chamber fibreglass filters etc still around - black box filters not very well looked upon by serious koi keepers unless they achieved the 1/3 surface area rule . New media - k1/bhm bakki showers and nexus, faster turn over [I wonder that the faster turn over accomodates the hardware of bakki and nexus rhater than the every 2-3 hr turn over on a much bigger filter surface area being inherently wrong].

So space saved and more efficient media and EASE of filter maintainance seems to be greatly improved. Does that rule out older methods... after all a multi chamber block built filter can utilise the new with the old can it not? static and fluidised k1 settlement japanese matting polishing.... Oyster shells do a job - question is whether you prefer to do that job in another way... they work... does that make them bselete or just a choice of an alternative way? Should mention bottom drains... same as before and after sleep except with the introduction of the aereated type, which seem to have attracted their own controversy...

My pond will have a combo of old and new... and will welcome the improvements in efficiency I see in the newer methods that for most part make life easier... oh how I will miss those wet and miserable feelings and being frowned on as I came in smelling of what my lovely koi didn;t want

What job do you think they do Dave and why / when would someone need them?

Regards

Davej

Hi Dave
The air is sweet my fish never smell of anything !!!... you really must stop giving your koi mushy pea's mate
rgrds
broxandval

Ok first will say I haven't used oyster shells but dragging from memory again... and thus standing in line to be shot heh... I believe they are used as a PH buffer - by that I mean sort of stabalising the PH in a kind of slow release. I suppose it could be thought of as working in the same way as if you were trickling bicarb? Helps prevent a PH crash in a sort of slow release kind of way... if I am right it would maybe benefit those that experienced reducing PH as a norm, as well as giving a degree of protection between ph checks? Question marks as I am not confident of my memory... hmmm may be something to consider if leaving pond for a period while on holiday and some valve turning in the hands of a 'non koi' helper ?

Brox... whats the matter with mushy peas mate? Mushy peas, chips and tray of gravey mmmmmm - koi delicacies

Ok daylight off to wrestle with the fittings on this damned QT sigh... AGAIN!

Oyster shells only start to react (dissolve) when the pH drops below pH 7 (pH 6.8 is their reaction point from memory). Above pH 7 they are inert. So not a bad way of protecting against a pH drop PROVIDING you have a ton of space. The odd bag here of there is just for decoriation.

Tom

Thanks Tom thats good proper info - always better than my rambling speculations heh

Oyster Shells or Shells in General comprise CACO3 ie Calcium Carbonate ...

This is a very poorly soluble species therefore Quantities as Tom stipulated are required to afford any manner of buffering capacity contribution with regard the general acidification respiration Processes occurring continuously in ponds with subsequent PH declines over time ..

It will however still "Buffer" at PH Values above the neutral 7 albeit to a much lesser degree not forgetting also that unlike Bicarb (baking soda) CC will add considerably to both the GH and TDS

With varying pH

We now consider the problem of the maximum solubility of calcium carbonate in normal atmospheric conditions (\scriptstyle P_{\mathrm{CO}_2} = 3.5 × 10−4 atm) when the pH of the solution is adjusted. This is for example the case in a swimming pool where the pH is maintained between 7 and 8 (by addition of sodium bisulfate NaHSO4 to decrease the pH or of sodium bicarbonate NaHCO3 to increase it). From the above equations for the solubility product, the hydration reaction and the two acid reactions, the following expression for the maximum [Ca2+] can be easily deduced:

[\text{Ca}^{2+}]_\text{max} = \frac{K_\text{sp}} {K_\text{h}K_\text{a1}K_\text{a2}k_\text{H}} \frac{[\text{H}^+]^2}{P_{\text{CO}_2}}

showing a quadratic dependence in [H+]. The numerical application with the above values of the constants gives[citation needed]
pH 7.0 7.2 7.4 7.6 7.8 8.0 8.2 8.27 8.4
[Ca2+]max (10−6mol/L) 180 71.7 28.5 11.4 4.52 1.80 0.717 0.519 0.285
[Ca2+]max (mg/L) 7.21 2.87 1.14 0.455 0.181 0.0721 0.0287 0.0208 0.0114



* decreasing the pH from 8 to 7 increases the maximum Ca2+ concentration by a factor 100. Water with a pH maintained to 7 can dissolve up to 15.9 g/L of CaCO3. This explains the high Ca2+ concentration in some mineral waters with pH close to 7.
* note that the Ca2+ concentration of the previous table is recovered for pH = 8.27
* keeping the pH to 7.4 in a swimming pool (which gives optimum HClO/ClO− ratio in the case of "chlorine" maintenance) results in a maximum Ca2+ concentration of 1010 mg/L. This means that successive cycles of water evaporation and partial renewing may result in a very hard water before CaCO3 precipitates

Being a huge Fan of Experimentation I ran a small 8 day exercise in this regard and the results are as follows ..

Starting PH was 7.2 KH was 40ppm and GH 62 ppm .. No respiration activity ie life forms were initially in situ this being "Tap Water" without chlorine ..

I didn`t have time to measure values daily but by day 2 the PH was 7.36 and steadily increased throughout as did the other values measured ...

Allowing for Evaporation concentration of both GH KH values increases .. Buffering did still occur ...

Bear with me re Pics these will take a second Post which I`ll try to upload later