Water ph mystery

Discussion in 'Newbies to Garden Ponds' started by richyd, Sep 8, 2012.

  1. richyd

    richyd

    Joined:
    Jul 10, 2012
    Messages:
    107
    Likes Received:
    14
    Location:
    UK
    As some of you are aware I've been having a few troubles with my pond.
    My ph has been rising slowly since the install. I've now got round to sealing my waterfall using G4 clear sealant. One of the unexpected things with this is that the algae can now longer grow on it, which Is a bonus.

    My ph has stabilized at around 8.5 midday and slightly lower at the evening.

    But something strange is going on. I've tested my tap water and its 7.6. I keep a water butt by my pond, I fill this up with tap water then use dechlorinater. This water is then used to top up the pond when necessary. But after two days of sitting in the water butt, i tested the water in there and it had rise to 8.5????? All i used was dechoninator, nothing else was in there. I was talking to a chap the other day and he mentioned this is something to do the the GH of my water.
    Our water company is renowned for having some of the softest water in the UK. I do not have a test kit for this, but I was wondering if this could be connected with the rising Ph? and if GH and PH are related in some way.

    This is my last problem left with the pond. Once i've got this sorted / understood I can start to relax and enjoy the pond :goldfish: .

    Please help me

    Thanks in advance :)
     
    richyd, Sep 8, 2012
    #1
    1. Advertisements

  2. richyd

    Waterbug

    Joined:
    Apr 10, 2010
    Messages:
    3,195
    Likes Received:
    1,260
    Location:
    Phoenix AZ
    I kind of just take each post as they come so I'm not aware of your troubles. But maybe I can offer some general pH stuff.

    Stable pH is more important than any specific pH value.

    Measuring pH is more tricky than most people think, and it tells less than most people think. Measuring KH tells you a lot more. It tells you the general pH range and more importantly it tells you what your pH will be tomorrow.

    Your tap water rise in pH...lots of possible causes. First up is the dechlorinator. Anytime you add something to water pH is likely to be effected. Second up to bat is CO2. Tap water can be high in CO2, that acts as an acid and lowers pH. Once exposed to the air some CO2 out gases and pH rises.

    GH
    GH is generally not tested by people because adjusting GH and the effects are complex and generally not needed to keep fish alive.

    To understand GH you need to understand KH first...
    To make things a bit easier lets say KH measures the amount of baking soda in your pond. Without any KH the pH can swing, hour by hour, from say 4.5 to 12. Those fast changes in pH stress fish and can lead to dead fish.

    As you add baking soda the KH level may not actually increase because the baking soda is being consumed by acid. If you keep adding baking soda the acid becomes all used up and KH will start to increase. At this point pH becomes kind of stable at lets say 7.5 pH, a great pH for Koi and Goldfish. Problem is acid is always being produced in a pond, plus rain is an acid (2.0 to 5.5). As that acid enters the pond it reacts with the baking soda using it up and KH starts to go down, but pH will stay pretty stable. This is why it's called "ph buffering". KH stops acid from lowering pH. However, as KH declines there comes a point when the "buffer" is no longer working and pH suddenly drops. We call that a pH crash, and pH will start swinging again too, and not car keys in a hat kind of way.

    So, what some people do is add enough baking soda so KH is in the 100-300 ppm range. KH has to be extremely high, like 5,000-10,000 ppm, to be a problem for fish. Getting KH to say 200 ppm gives the pond keeper some breathing room. They don't have to worry about a crash in the short term. They can measure KH in a week and see where it is. If its 190 they know they maybe only have to check it once a month. If it's 100 they know they have to check it every week or more.

    Hopefully you can see why knowing KH tells you so much more than pH.

    However, as you add more baking soda and KH increases so does pH. What baking soda does is stop pH from falling, it doesn't stop pH from rising. The result of just getting KH up is pH will rise into the 8.5 - 10 range. That's pretty stable pH. Pond fish can deal with that pretty well. Most people who get this far call it a day here. Good enough, crack open a beer, Goodnight Irene.

    Different parts of the world have different levels of KH in their source water. People in areas with high KH source water and low fish loads never have to learn about all this. Often they'll say "oh you don't need to worry about KH and all that non-sense" thinking if they don't then certainly no one else does either. People with low KH source water like you do have to be concerned...normally starting the day after all their fish die.

    Now for GH...
    A good GH level, say 100-250 ppm stops the baking soda from pushing pH above about 8.5. The net result is KH stopping pH from going below 8.3 and GH stopping pH from going above 8.5. Result is a very stable pH of 8.3 to 8.4.

    I don't know if the chap you spoke to knew what hie was talking about, but he may have. GH could be stopping your water from going above 8.5. However, for GH to do this there must be KH, and of course a good GH level. Good GH and zero KH results in pH swings. GH on it's own has little effect.

    You may often read people write, my posts included, that adjusting KH gives a pond stable pH of 8.3 or 8.4. But that assumes a good GH level so not he whole story. But most people don't really want the whole story either.

    KH is a "temporary buffer" and GH is a "permanent buffer". GH isn't consumed. So generally it needs little or no adjustment once set. KH has to be adjusted, sometimes often. Whether the adjustment is adding baking soda or new source water.

    Adjusting KH and GH...
    Baking soda is one way to raise KH. There are many other ways, oyster shells, egg shells, plaster, limestone, concrete, on and on. These are are commonly touted by more inexperienced keepers because they sound like more friendly things. Who doesn't like an oyster shell? However these are very poor pH buffers (some aren't even buffers at all, just sound like they should be) because it takes the acid a while to get to the shells and then to break it down. Baking soda is dissolved in the water ready to bump into any bit of acid and almost instantly cancel out the acid. So with just oyster shells you can see a crash after a thunderstorm, but pH will recover, so the fish aren't completely stressed out. For people who care about really stable pH baking soda is a reasonable choice.

    Things like oyster shells can be made better pH buffers. Crushed oyster shells, called grit and sold as a supplement for chickens, is a much better buffer. More surface area = faster acid reduction. Crushed into a power is even better but that's basically the same as baking soda which is cheaper and easier to find. Placing the oyster shells in moving water can help a little too.

    People really get skittish when it comes to adjusting GH which is another reason people don't bother with GH. GH measures magnesium and calcium. Epsom salt is a reasonable source of magnesium. Gardeners you know about adding Epsom salt to plants may not have a problem adding this to ponds but many people do because it doesn't sound right.

    A good source of calcium is calcium chloride flake...the de-icing stuff at the hardware store used to sprinkle on the sidewalk to melt ide. Few people can bring themselves to add that to their pond, but it is safe if you read the ingredient list to confirm.

    Why KH is good beyond pH buffering...
    The bacteria that converts ammonia also needs O2 and carbon to complete the conversion. Low KH can lead to high ammonia and nitrite levels, deadly. Combined that with pH swings and the fish haven't got a chance.

    Keepers with large fish loads have bio filters that convert a lot of ammonia, using up KH really fast. They can be adding a pound of baking soda a week to keep up.
     
    Waterbug, Sep 9, 2012
    #2
    fishin4cars, HARO and richyd like this.
    1. Advertisements

  3. richyd

    richyd

    Joined:
    Jul 10, 2012
    Messages:
    107
    Likes Received:
    14
    Location:
    UK
    Thank you so much Waterbug for your time. I will take your notes on-board, much appreciated :).
     
    richyd, Sep 9, 2012
    #3
  4. richyd

    Waterbug

    Joined:
    Apr 10, 2010
    Messages:
    3,195
    Likes Received:
    1,260
    Location:
    Phoenix AZ
    You're welcome. I've wanting to write that for awhile. Normally I just say Google "pond pH buffering", which is still a good idea.

    Oh, I forgot on the GH...the calcium is the part that limits pH to 8.5, not the magnesium.

    And GH being called "permanent buffer" is related only to how it interacts with KH. Magnesium is used by plants and calcium is used by bugs and fish to grow shells and bones. So it can go down.
     
    Waterbug, Sep 9, 2012
    #4
  5. richyd

    jhenkel

    Joined:
    Nov 12, 2006
    Messages:
    63
    Likes Received:
    6
    Location:
    Woodstock, Georgia
    Waterbug - shalom, on previous posts I've made you've commented about the use of plaster of paris in regard to ph buffering, and, from what I've seen of your posts, if I understsand correctly, you don't really consider it a good ph buffer, which you referenced documentation, and which I understand. My comment is that I keep a block in the skimmer with the pump, have been doing it for several years and the fish are healthy, so that being said, and, I've used some barley extract(not much) this year. Most of what I used was in the small preformed pond which I guess is around a 85 gallons so that water has been warmer, but now that the lillies have covered the pond, algae is not a problem.

    Having gone around the mountain one more time, would it not be reasonable to say the plaster of paris has been a postive influence or postibve factor in assisting with the stabilization of the ph in my two ponds- one pond around 600+ gallons, and the other around 85 gallons?

    Thanks,
    McKool
     
    jhenkel, Sep 9, 2012
    #5
  6. richyd

    Waterbug

    Joined:
    Apr 10, 2010
    Messages:
    3,195
    Likes Received:
    1,260
    Location:
    Phoenix AZ
    It wouldn't be reasonable for me to say that as I don't believe it to be true. I know this bugs the living heck out of a lot of people, a ton of people, but I'm just not into the logic I often read or hear at dinner parties where the basic premise is along the the lines of "I put X in my pond, my pond is good, so X must be the reason". I'm into science. I like to understand the whys. I don't really care if 99% of the world believes the earth is flat or whatever. I don't believe opinion is the same as facts. Sorry.

    Plaster of Paris can be anything, it's not a Trademark, or regulated as far as I know. I can call my left toe Plaster of Paris. However, as far as I can tell, from several sources, the common definition of pop is basically CaSO4, depending on form.

    If a person chooses they can mix in something else, even baking soda, and make a block of white stuff, call it Plaster of Paris. This Doc Johnson article would probably be more to your liking. He references something called Home Depot calls Plaster of Paris that is 50% limestone and 50% CaSo4 (actual pop) or the PH Pill which is 75% limestone and 25% CaSo4. He also goes on a rant about people saying C.A.S is calcium sulfate which I didn't really understand, the Gypsum part he references is indeed calcium sulfate dihydrate. My local Home Depot today is selling pop that is 15-25% limestone.

    Which ever one believes is pop, or limestone, or whatever there is a bottom line. All of these chemicals just have a very low solubility KH wise. It would take huge amounts to make a KH difference. This is why pop is not a good pH buffer...maybe not even a pH buffer at all pond wise.

    I think the confusion is that if you pour acid onto pop or limestone it will bubble and neutralize the acid. That's not the same thing as a pond pH buffer.

    Here is the definitive text on Plaster of Paris not being a pH buffer imo. For me this is the kind of detailed info I can cross check and is what I look for to learn about stuff.

    Putting aside Plaster of Paris being bad at rising KH, let's talk chunks...
    For people who don't like all the chemical bah, bah, bah there is an easier way to understand this imo...a big chunk of of the world's most perfect pH buffer, whatever that is, will not dissolve in water very fast. A big chunk of ice in water won't even dissolve very fast.

    Even a chunk of natural baking soda is going to be a poor pH buffer imo simply based on it not being able to dissolve fast enough in some cases. If acid slowly increases and the chunk can dissolve fast enough then sure, it's a pH buffer. That's a big if in my book. A needless risk.

    Given two choices, big chunk or completely dissolved in water I gotta pick the dissolved form. Then I don't have to worry about Doc Johnson's disclaimer at all.

    If a person didn't believe in science and still considered Plaster of Paris to be a good pH buffer I have to ask...why cast it into a chunk? Why not dissolve the powder form directly into the pond? That would solve the chunk problem. And pop is cheaper than baking soda.
     
    Waterbug, Sep 9, 2012
    #6
    HARO likes this.
  7. richyd

    richyd

    Joined:
    Jul 10, 2012
    Messages:
    107
    Likes Received:
    14
    Location:
    UK
    I think i'm starting to understand this now. Still waiting for my new test kit to arrive which measures KH and a few other parameters. In the mean time I have purchased some Aquahumin from Oase. Basically a mesh bag full of peat balls. Should start to gradually bring the ph down. The instructions state

    Special peat for garden ponds. Free from chemical additives, nematodes, pathogens and substances toxic to plants.
    • 30-45% humic acid
    • Softens the water
    • Lowers the pH value
    • Reduces algae growth
    • Clarifies murky water
    • Restores the biological balance
    Its all I can think of while I wait for my test kit. Does this stuff sound ok? Anyone have experience with this product
     
    richyd, Sep 11, 2012
    #7
  8. richyd

    sissy sissy

    Joined:
    Jan 17, 2011
    Messages:
    30,008
    Likes Received:
    13,288
    Location:
    Axton virginia
    none here and my ph stays at 9 and if you lower it to low and not sure what kind of fish you have but it will stress them out .Mine stays at a stable 9 and never have lost a koi in 8 years .so it must be fine for them and 2 of them are over 2 feet .
     
    sissy, Sep 11, 2012
    #8
  9. richyd

    crsublette coyotes call me Charles

    Joined:
    Oct 23, 2011
    Messages:
    2,678
    Likes Received:
    1,096
    Location:
    Dalhart Texas
    I would get that figured out, urgently. Make sure your pH tester is not faulty. If you do any water changes, then make sure it's done not to cause any harmful pH swings. A constant trickle water change could resolve this potential pH swing.

    To clear up one thing ... Ammonia toxicity signficantly increases with pH increase. There has been articles investigating bacteria's conversion rates effectiveness with various factors such as salinity, pH, water temperature, and other variables. pH of around 7.8~8.3 has shown to be the most optimum environment for bacteria processing ammonia and nitrite, and also indicating a decrease in effectiveness when the pH is far too much beyond these levels. Any decrease in effectiveness would indicate higher bacteria population required to process the ammonia and nitrites. I have read a few of these articles and their conclusions fluctuate between them all so I have averaged it out to figure 7.8~8.3. My water is crazy hard so I diluted most of the KH with de-ionized reverse osmosis water then used 2% muriatic acid to further dilute it to the 8.0 pH; these adjustments may not be realistic for big pond.

    Generally, higher KH is said to be better since lower KH is what can cause a pH crash and bacteria processing waste consumes KH further lowering it. As long as you have hard water species in the water, such as koi and comets, a high pH will be completely fine for them as long as you keep the ammonia toxicity in check.


    It might be that particular brand of dechlorinator. I have played around with quite a few pond products and some of them definitely had an impact on my pH.

    KH is primary element that can raise pH since it does not take much KH to change the pH. pH can also raise due to many other elements, such as phosphorus, at very high volumes. If you have to use a huge amount of phosphoric acid to lower pH, then better to use muriatic acid or other sources.
     
    crsublette, Sep 26, 2012
    #9
  10. richyd

    Waterbug

    Joined:
    Apr 10, 2010
    Messages:
    3,195
    Likes Received:
    1,260
    Location:
    Phoenix AZ
    I have no experience with this product or peat. All acids can lower pH if enough is added. Assuming a reasonable KH number, say 150-300 ppm, as you add acid pH will not change, but KH will start to drop. When KH gets below say 100 pH may drop, as KH gets to say 50-70 pH will drop more, maybe to 7.5 or so, as KH approaches 0 pH will drop very fast, maybe into the 6.0 zip code. At that point the good bacteria start to die and fish are stressed by the sudden pH change. With low KH the small changes in CO2 between day and night may cause pH to swing say between 5.0 and 14.0. That's called a "pH swing". More fish stress and without the bacteria working ammonia starts to climb stressing fish more. Normally the first sign a keeper sees is belly up fish. Then they get a test kit, or just get more fish.

    KH can be lowered with acid, peat or otherwise, if a pond keeper really wants a specific pH. But pH will not be stable unless water parameters are monitored like daily and adjusted with great care. Things as minor as a thunderstorm, with rain being 2.0-5.5 pH can pH crash such a pond so the keeper really has to be on their toes. I've read of a very few pond keepers who do this. Many aquarium keepers do this because their animals require a specific pH and/or they want other things in peat.

    If I was going to play with KH and pH I would not use peat because the rate of acid release wouldn't be under my control. When playing this game control is needed.

    However, having said all that I doubt AquaActiv AquaHumin would really have much effect on anything beyond maybe turning your water brown. Depending on pond size it would probably take a lot of peat to effect things much. But who knows.

    If it does turn your water brown and you want it clear again the easiest way to do repeated water changes until the water is clear enough for your tastes.
     
    Waterbug, Sep 26, 2012
    #10
  11. richyd

    crsublette coyotes call me Charles

    Joined:
    Oct 23, 2011
    Messages:
    2,678
    Likes Received:
    1,096
    Location:
    Dalhart Texas
    I have looked into peat. It is much like trying to raise KH with crushed oyster shell in that it is slow to cause a change. It appears to be effective, but far too slow for me.

    It really is not that difficult. I have read it mainly done in aquaponic systems where constant pH monitors and automatic dosing machines with highly concentrated pH adjustors to easily maintain proper pH. These machines cost just as much, sometimes less, as the fancy mechanical filtration you can buy for ponds, but I built a system that does it somewhat well and it does take more of my attention than I desire.

    There actually are soft water ponds, in around the 7.8 range, out there. This is not uncommon.

    In my area, with extremely hard water, it takes a HUGE amount of rain to actually affect pH dependent upon the volume of the water. The rain aroud my area hovers around 5.7ph, according to the acid rain charts I have read.

    I have a 435 gallon water feature. My well water has a 8.5 pH with KH of 196.9 (11 degrees) and GH of 250.6 (14 degrees). To dilute my water, I had to literally add around 200 gallons of di-RO water, that is nearly 50% of my watergarden's capacity, to bring my water down to 8.1 pH, KH of 106.8 (6 degrees), GH of 124.6 (7 degrees). I need to add just a few more gallons of di-RO water to bring my KH down another 17.8 points, or one degree lower, so I can reach a pH of around 7.6~7.8. De-ionized reverse osmosis (di-RO) water has 0 KH, 0 GH, and a pH of 5.0. So, with the acid rain of 5.7ph in my area, it would take even more water to cause an affect.

    Total volume of KH is mutually exclusive with total volume of pond water. I was chatting with Addy a few months ago about this. With her natural soft water ~10,000 gallon pond of around 7.8, I was guessing it would take 500 gallons, if not more, of rain water to change just 1 degree of KH. 500 gallons of rain water can be easily achieved IF you specifically have drainage of rain water going directly into your pond. However, it appears she has a huge amount of crushed oyster shells to easily compensate for these occurences.

    Also, a concern of CO2 consuming KH released by oxygenating plants, algae, and decay. CO2 is one of the main reasons causing potential pH swings between morning and evening pH tests. So, this has to be taken into consideration. However, takes quite a bit of CO2 to consume 1 degree of KH.

    KH consumption is dependent on the bioactivity in the pond volume. Generally, I have read on koiphen to stay above 80 ppm KH (4.5 dKH); if it goes below this, then it can be easily fixed by baking soda. My comfort zone is no less than 6 dkh (106.8 ppm) since it takes less maintenance to maintain by heavy rains and CO2. I have heard of koi ponds intentially being 53~89 ppm KH, but these were indoor ponds; personally, I would never go this low.

    This is why hard water is better since you have less worries and it is much easier to deal with ammonia toxicity by simply increasing bio-filtration to allow bacteria to reach higher populations or use ammonia chemical binder.

    Hard water species are more concerned about the mineral content, the GH rating, more than any KH rating as long as the KH supports aquatic life and changes in bio-filtration to compensate for the affect of bacteria's effectiveness.

    I never heard of acid rain being below 4 pH in the States here, not saying it doesn't happen though.
     
    crsublette, Sep 26, 2012
    #11
  12. richyd

    Waterbug

    Joined:
    Apr 10, 2010
    Messages:
    3,195
    Likes Received:
    1,260
    Location:
    Phoenix AZ
    "Acidity" section.
     
    Waterbug, Sep 26, 2012
    #12
  13. richyd

    crsublette coyotes call me Charles

    Joined:
    Oct 23, 2011
    Messages:
    2,678
    Likes Received:
    1,096
    Location:
    Dalhart Texas
    Yeah, did a google search "2.0 ph acidic rain". It appears a 2.0 pH rain, or anywhere near, is a rare occurence and even just a 3.6 pH rain only happens in particular areas. Makes ya wonder if these areas with very low pH rains makes particular bodies of water to have a fish kill or a pH crash after a rain.

    Interesting. Heh, out of curiosity, makes me want to pH test the water in my rain gauge after each storm from now on to see how low the rain water pH actually can occur here. If it ever would rain here, grr..
     
    crsublette, Sep 27, 2012
    #13
  14. richyd

    Waterbug

    Joined:
    Apr 10, 2010
    Messages:
    3,195
    Likes Received:
    1,260
    Location:
    Phoenix AZ
    Yeah, I can't really predict the pH of rain. It's just something worth considering at least for me.

    I don't think lakes would be affected by local thunderstorms. Pretty large bodies of water. Long term acid rain sure, many have. A shallow pond with low KH like someone trying to keep water at 7.0 pH, 1-2" of low pH water could have a big impact on KH and then pH. If I was keeping low KH intentionally, I'd want to be aware of rain pH. But I don't think I'd ever keep low KH.
     
    Waterbug, Sep 27, 2012
    #14
  15. richyd

    crsublette coyotes call me Charles

    Joined:
    Oct 23, 2011
    Messages:
    2,678
    Likes Received:
    1,096
    Location:
    Dalhart Texas
    That's one thing. Then, also being so conservative that ya miss out learning something.

    I wasn't specifically thinking of lakes. I know the volume of KH in these would be so large that it would take a tremendous amount of rain to specifically be routed to drain into the lake to have any affect on the KH.

    And depends on how often water changes and daily or weekly water adjustments occur.

    I don't know of anyone who keeps an outdoor pond at 7.0pH. That's crazy. Maybe an indoor aquarium or pond, sure.

    Here's the deal. 1" of rain on 90 sq. feet area, size of my watergarden including stream area, a 1" rain gains me ~56 gallons. My berms are at least 4" tall so I have zero extra drainage entering the pond. With di-RO water, that is 5.0pH, litterally took 49%, that is 200 gallons, of my watergarden's total volume to lower 4 dKH. I also have a 20% daily water change from my constant trickle flow which is about 4 gallons of refreshed KH water per hour. A 3" rain, within one hour, is extremely rare in my area and it has not happened since the early 80s, late 1970s. From all the charts, it appears the acid rain in my area is 5.6pH, but there could be that one instance where it is like 3.6pH. So, how much 3.6pH rain would be required to cause a 2 dKH swing in my pH. It appears I would litterally have to have a little more than 2" of ~2.5pH rain within one hour for my very small 435 gallon, 7.8pH, watergarden to pH crash. I really don't see a 2.5 pH rain occurring in my region, but I'll be testing my rain to find out, it will be interesting.

    If you're not doing a constant trickle water change system or zero daily/weekly water changes, then this changes things a bit.

    Interesting to know that 10% concentrated Muriatic Acid has around a -0.1 pH, that's a negative .1 pH.

    I created a thread on koiphen. "rain and pond pH, what are your experiences??". One poster said after an extremely heavy rain in Long Beach, Cailfornia, where they actually can get 1~2" of rain within an hour, wrote that her pond experienced a crash, which I am suspecting her pond was likely around the 7.4~7.6pH range. Yeah, it all depends where you live. I would keep caution when having a 7.6 pH pond in the east or west coast, particularly where there is a high level of air polution, indicating a lower pH rain. However, there's a fella, in Washington where it rains consisently and his source water is 1~2 dkh, he has not had a pH crash, but he has a high level hourly water change system.

    I imagine a fella doing some sort of constant trickle change, where his source water is extremely soft, would be consistently adding a ton of baking soda, excluding the acidic rain potential, to maintain anything near 8.0 pH.

    It'd be an interesting experiment.
     
    crsublette, Sep 28, 2012
    #15
  16. richyd

    addy1 water gardener / gold fish and shubunkins Moderator

    Joined:
    Jun 23, 2010
    Messages:
    32,313
    Likes Received:
    16,591
    Location:
    Frederick, Maryland
    My pond ph sits around 7.5, this am it was 7.3 per my meter. We have had a lot of rain this week. Rain, well water both acidic and soft. I have not measured anything higher than 7.6 all summer, but it is stable.
     
    addy1, Sep 28, 2012
    #16
    1. Advertisements

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.