Ph Swings

[wallo69]

Hi Dunc,

Its been a relatively trouble free year so far (hope not to jinx myself there ) but fellow hobbyists and myself have still issues with pH swings, despite having reasonable kH levels in the pond.

Andy Finch has had a few issues with treating for blanket weed with Kusuri Eco Gold when he went on holiday to find levels of carbonic anhydrase killing an upsetting number of koi before getting the water changed enough to get on top of it, thankfully now in control, but with little feeding going on, so still not out of the woods.... however, currently despite a kh level of 3degrees suffering massive ph swing of 7.1 to 8.1 which may explain (or be because of) the lack of feeding?

Personally I have see high pH levels (and swings) despite only having a low kh of 1 for most of the year, but I have put this down to the reduced number of koi in my pond going from 31 to 10 at the beginning of the year. My ph has been as high as 7.8 but no lower than 7.1

We both use RO and add bicarb to dose up the kh, but Andy has been adding purified tap water back (since the health issues at the beginning of the month) due to concerns over the quality of the bicarb being used, but all of the forgoing has left us feeling uncertain over how best to manage pH with large ph swings despite the 'reasonable' kh in his pond in particular.

This leads onto the question, which is worst for koi development and general health, a low TDS (relative to GH) pond with large pH swings or a stable, clean pond of a higher ph say of 8.4 with a high GH level but a stable ph?

We would be interested in opinions on this point in particular.

Thanks for reading,

Mark

[Duncan]

two questions

1 whats you GH reading?
2 whjats your level of algae like in the pond?
well 3 i dont suppose you measure phosphates?

dunc
p/s im busy at the moment so please bare with me

[wallo69]

Hi Dunc,

Not rush with this topic, as its an ongoing issue, but to answer your points;-

1 GH at most 1 degree as the colour is very light at this end when testing.

2 I have a layer of 'matting' around my pond, which never gets too bad, but I know Andy had a healthier level in the pond, hence the treatment with Eco Gold, but I think he still has it on the walls, like I do, as that is all the fish seem interested in at present.

3 No, not tested for phosphates, but I have a API test kit, so will do that next, see what we find.

If your though process is going where I think it is, with the weed having its affects on pH as you might expect, then this brings us onto another question, how safe are the current blanketweed treatments, ie Kusuri ECO gold used in a low ph/TDS/RO pond?

I respect of the phosphate levels, I know in discussions I have had on a Marine Forum they advise the reduction of nitrates and phosphates as the key to managing all green stuff growth, so I would hazzard a guess this is the matter here in our ponds? Dilute out or as Andy is able to do in his pond, 'recycle his water' through an RO filter, stripping these compounds out as well.

In regards to the BW treatment of Andy's pond, with him being away on holiday for a fortnight after he treated he cant be certain this is what caused the mortalities in his pond, but with his covers still on at the time (quite airtight as well) and they were feeding well before he went on holiday, this is still 'my opinion', that the treatment, which I understand has zinc in it, has poisoned the koi, and its only water changes that have got the levels of carbonic anahydrase reduced to a safe level.

So is this a dosing issue, in respect of the product? Should the manufacturer be stating such in their literature, that the kh buffering capacity of the pond will affect the strength of the dose?

Interested to hear more thoughts on this Dunc, as and when.

Regards,

Mark

[Duncan]

just quickly

over a 24 hour period i would expect you water to be more acidic in the morning and more base in the evening, is this what your seeing

the key to managing weed is to manage your nitrates and phosphates both are the fuel for algae and thus your weed

gotta run

dunc

[greg]

Mark,

Important here to remember we are not just talking "wall" algae - the free swimming stuff will also affect the PH. Eg:- Full sun and photosynthesis will take place and this will cause swings. IMO even with the UV on as it will not keep up with the natural process in most ponds on really sunny days.

Interestingly - i wonder if there was a "greenhouse effect" by leaving the covers on and it warming the pond enough to produce extra growth.

Also you need to factor in the PH probe accuracy / reliability / calibration etc.

Also note:- Carbonic Acid is a by product of the nitrogen cycle in filters that are left for periods between cleans. In Andy's case i wonder if the rapid "shed" of algae and the subsequent drop in levels has led to a build up of waste in the large settlement and this has in turn meant a production of carbonic acid as it wasn't cleaned while he was on holiday. I know you guys as digging deep for answers but is suspect even with the investigations your doing you will never truly know the answer.

Lots to take into account here and many variables IMO.

In terms of the PH stability - what point do you need to get to on the KH scale to stop / reduce the swings to acceptable amounts?

My honest answer / opinion is that if it was my pond i would be coming up above the desired running readings using standard tap water to a point where it was all much more stable and then begin the "RO run down again" trying to get where you want to be with stability. The other question is - when did the instability start? can it be linked to regime changes (eg you mention stocking) - does the balance of the pond need re-addressing?

[wallo69]

Hi Greg (seriously been meaning to ring for a chat, and will do!),

Yes, lots to think of, and its always difficult to detract from the vairables affecting an 'incident' like Andy has suffered, and the long term 'management' of pH, but your points, like many we have discussed are anecdotal now, as unfortunately we are too far past the incident to ever get to the bottom of the full 'sequence of events' and understand what has happened.

To touch on the after affects, we still have unsettled koi in Andys pond, and he has gone to lengths to get every last trace of the treatment out of the system to get them on track again, so that will hopefully sort itself out in time.

Of course, your post seems to have missed the matter of toxins, and the link to Kusuri's product containing zinc, but I hazzard a guess that wasnt unintentional but still leaves a serious question for the 'low TDS' brigade, is it 'dont use' or reduce to x%, or still unsafe, so get a ph of 8.4 before you consider treating?!?

Longer term, I think Duncs post, quick and directly to the point of the matter - how best to get these algae feeding DOC's out, strip with RO filters, protein skimmers, or bugger the cost, water changes resembling a open system.... I guess horses for courses is the answer here.

Regards,

Mark

[greg]

Mark,

Totally ignore Andy's situation that i touched on above. Take the line below out of the post above:-

In Andy's case i wonder if the rapid "shed" of algae and the subsequent drop in levels has led to a build up of waste in the large settlement and this has in turn meant a production of carbonic acid as it wasn't cleaned while he was on holiday. I know you guys as digging deep for answers but is suspect even with the investigations your doing you will never truly know the answer.

......and the comments i make in my original reply still apply for PH swings which was the original question. Feel i may have muddied the reply with that sentence or two and that was not my intention.

As for the BW product and not mentioning Zinc - cannot comment as i don't know for certain that it does. Have used it myself (and the CBA one too) with zero issues so dunno

[wallo69]

Greg,

The levels of carnbonic anhydrase in the blood that paula reynolds found were toxic, and relate to zinc (dont ask me how ) but they dont get elevated on their own!

Granted, its got to be a combination of factors, but we all know too often hobbyists falling foul of these 'chemical' treatments, and with the industries approach of 'if we dont need to put people off with overcomplicated advice (legally that is) we wont' we are fools to think they are safe!

Back to Dunc's last query - tested phosphates tonight - 0.50 mg/l which aint much health wise, but I am sure far too much if we are trying to avoid weed growth!

Will have to test Andy's but after all his water changing I would guess he is much less than he was.

Mark

[ageinghippy]

Mark

With regards to zinc in the blanketweed treatments, I`m sure that it was `mankysanky` that did research into the subject a year or might be two ago, and concluded that they were safe for us to use. Would it be an idea/useful if you had a word with him?


Chris (another one)

[finkoi]

Hi
Mark we are still not sure there is any Zinc in the treatment I used as it is still being tested? What has already been said is that zinc is far more toxic at a lower PH say 7.0 and safer the higher the PH.

We are still guessing on what could have happened and would not want to replicate the conditions to find out what happened as it was devastation!

What I would say to people that run RO it would be safer to raise your PH before treatments.

My particular situation caused a raised level of Carbonic Anhydrase in the blood which in effect caused what deep sea divers call the bends in the fish! My PH is now starting to stabilise after doing loads of water changes to try and dilute out what ever toxins were in the water. I hope I have turned the corner now.

Chris Blanket weed treatments may have been tested to be safe to use in our ponds. Ignoring what happened in my case I know for a fact that Paula Reynolds gets phone calls almost ever week from people loosing fish after using blanket weed treatments. They may be safe to use but every pond is different and some times the water conditions could have been better before people added the treatments.
I have used blanket weed treatments many times in the past with out any problems but this was the first time I had treated since using RO.

I am very interested to know what the ideal water conditions are so that we don't promote the growth of blanket weed. What is the ideal phosphate and nitrate levels in a pond? Also is it easy to manipulate the water so to speak so we can stop it growing.

Also is there anything we can do to keep the PH swings to a minimum?

Andy

[Duncan]

Hi
Mark we are still not sure there is any Zinc in the treatment I used as it is still being tested? What has already been said is that zinc is far more toxic at a lower PH say 7.0 and safer the higher the PH.



Also is there anything we can do to keep the PH swings to a minimum?

Andy

well zinc is far more soluble at lower pH and zinc itself has a pH value of around 5-6

Extract "There is no single value -- the solubility depends upon the properties of the water. For example, the solubility increases as acidity increases (also known as lowering of pH), temperature increases, chlorine concentration increases and hardness decreases.

However, for ordinary water, the solubility of zinc is often limited by how much can dissolve before zinc hydroxide forms. From the solubility product, Ksp, for zinc hydroxide Zn(OH)2, and the pH value of the water, the solubility of zinc can be calculated. At room temperature, a water with pH = 7 (neutral) will have a dissolved zinc concentration, Zn(+2), of 0.29 grams per Liter = 290 ppm (parts per million, by weight) = 0.039 oz. (wt.) per gallon. If the pH increases to 8, the solubility decreases by a factor of 100, to 2.9 ppm. A chart showing Zn solubility at different pH values is at http://www.finishing.com/Library/metalpH.html The solubility values shown on this chart are lower than those calculated above because they were measured for hard water containing several dissolved metals."

There is no doubt about it if your GH value is less than your KH value then your swings are due to algae and photosyntheses during the night the algae takes in Oxygen and releases CO2 this forms carbonic acid lowering your pH, during the day algae takes in CO2 and releases Oxygen raising the pH this is where your swing is coming from the degree of the swing depends on the amount of algae and the size of your buffer

low KH & lots of algae = big swing
high KH & small amounts of algae = small swing ( but you will get a swing)

dunc

[wallo69]

Mark we are still not sure there is any Zinc in the treatment I used as it is still being tested? What has already been said is that zinc is far more toxic at a lower PH say 7.0 and safer the higher the PH.

I am very interested to know what the ideal water conditions are so that we don't promote the growth of blanket weed. What is the ideal phosphate and nitrate levels in a pond? Also is it easy to manipulate the water so to speak so we can stop it growing.

Also is there anything we can do to keep the PH swings to a minimum?

Andy

Andy,

From what our mutual friend in the business suggested Kusuri's new product has not zinc added, but the mined product used still had an element of zinc in its natual form? thats if I remember the discussion correctly.

Dunc's post suggests the various factors that were present in your pond, low pH, high temps (was over 20% when we checked) and the elevated levels of carbonic anhydrase were caused by something.... if not zinc then what else? OK I know you have concerns over the purity of the bicarb we have been using so thats another one to check, but we have been using that for the last 12-24 months.....

I know we aint gonna get an answer really, but as you say, there are enough hobbysists suffering from the use of the chemical treatments that we should look at the alternatives.

How do we minimise blanketweek and hence the ph swings? If I go by my marine 'ideal levels' of nitrate and phoshpate, I would say its nil for the pond as well! So its back to the extreme water changes to dilute or..... RO water recycling!!!

Mark

PS Another reason for me to get the new gear up and running asap! Will being seeing your mate tomorrow for the membranes!

[greg]

There is no doubt about it if your GH value is less than your KH value then your swings are due to algae and photosyntheses during the night the algae takes in Oxygen and releases CO2 this forms carbonic acid lowering your pH, during the day algae takes in CO2 and releases Oxygen raising the pH this is where your swing is coming from the degree of the swing depends on the amount of algae and the size of your buffer

low KH & lots of algae = big swing
high KH & small amounts of algae = small swing ( but you will get a swing)

dunc

Mark,

Taking Duncan's bit of info here... could this be the issue and why your seeing such swings. Running the GH under the KH level and then algae etc and of course i know you guys are running lower than me these days on the KH front. I would suggest that with the RO-Recycling and Bi-Carb dosing you will have a GH that is pretty much no existent and therefore

I see very little swing and i am wondering if that is because i'm currently running:-

PH 7.1-7.2
KH 2
GH 2
TDS 154

Try buffering with a little tap water instead of Bi-Carb to increase your GH levels and see what reaction you get?? Does the PH stabalise?

[wallo69]

Greg,

This possibly is the issue, non existant GH not helping with such levels of nitrate and phosphate in the pond, however I would guess the success of your pond is more likely due to the extreme water replacement reducing levels of these two rather than the presence of GH.

Have you tested for nitrate and phosphate? Would be interesting to see if this is the case or not?

Personally it all goes back to the need for managing water usage, and for me I cant afford the water changes you can, so I will continue to look at the modern alternatives.

Then there is the issue of what is in the GH? Going forward, if anyone can demonstrate what we need from our tap GH then I would selectively add 'mineral X' to an accepted 'beneficial' level, but until then, I dont see the point.

Mark

[greg]

Mark,

Your right, I am in the lucky position of not needing to worry about how much water I use or what it costs. So this enables me to change a high rate which gives me great stability in the pond and do whatever I need to in order to keep the readings I want.

Never tested for phosphate
Nitrate is today BETWEEN 25-50ppm

GH is a odd one in that I see a lower reading is better for MY KOI but think we need a touch of it in the concrete pond. I have come to accept that I cannot control EVERY single thing that goes into my pond water and as such don't worry so much what exactly makes up my GH these days. More about, if the readings are a little high or a little low and just make adjustments as needed. Maybe my GH of 2gdh does contain some thing the koi don't need / want but I don't have the time to control in that much detail. So simply settle for doing the best I can with what I have which seems to be doing OK so far.

Saw on another forum the other day the term - slave to the meter - 100% don't want to become that.

Can fully understand why your looking at the modern alternatives - but do bear in mind mate the old saying - "The solution to pollution is dilution" - you are not in an environmentally friendly or cost effective hobby and you will need to IMO strike a balance between the modern and the old to reach a balance and this i suspect will involve you adding more purified RAW water than you are thinking / wanting too being on a meter and that will have the implications you talk about cost wise.

I've said all along if they force me onto a water meter I would consider just packing in and walking away because I couldn't do what I believe is right for my koi.