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pH Issues

Discussion in 'Tropical Discussion' started by Ivan Mann, Aug 22, 2019.

  1. Ivan Mann

    Ivan Mann New Member

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    I have three tanks, a 20 gal community tank, 30 gal community tank, and a 55 gal Malawi Cichlid tank. The pH should be 7.5, 7.5, and 8.6, respectively.

    The pH falls constantly, and I put pH Up in fairly often. We just came back from three weeks out of town and the pH was 6.4, 7.2, and 7.5 in the three tanks (and a cichlid was dead). This constant drop in pH has been going on for years and I can't find any reason for it, and can't figure out what to do.

    Water coming out of the tap varies between 7.6 and 7.8. I siphon junk out of the tanks once a month or so, and pour a couple of gallons in every tank every week to make up for evaporation. Possibly related to the issue is that all three tanks have a lot of white scale which I scrape off every now and then. I have not analyzed it but I expect it is calcium, so take that out of the water and it will become more acidic, but the question remains, what do I do? I would prefer some solution other than constant pH Up.
     
  2. Byron

    Byron Member

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    The pH changes are natural and I can explain those. The GH and KH are inter-connected to the pH. We need to know the GH and KH of your tap water; if you don't know these now, you should be able to ascertain them from the municipal water authority, check their website or call them. We need the number and their unit of measure (there are several around, different of course).

    While waiting for the numbers...do NOT use pH adjusting chemicals in any tank with fish. These solutions do not usually work long-term, as you have seen, and the fluctuating pH is much worse on fish. This is most likely the cause of the dead cichlid; a pH of 7.5 would be easier on rift lake cichlids than regular fluctuating from 8.6 to 7.5 and back.

    The pH is tied to the GH and KH. The latter "buffers" the pH, preventing it from fluctuating. The higher the GH and KH, the more buffering capability. When you use the pH adjusting solution, whichever (up or down), it temporarily changes the pH but the buffering kicks in and the pH goes back to where it was. The only way to adjust pH is to first deal with the GH and KH. I can explain this more once I know the numbers.

    Another generality is that the pH will naturally lower as organics accumulate and decompose. This is normal in any aquarium with fish. The buffering capability of the GH/KH works to off-set this, depending what it is. In tanks with hard water having a fairly high KH, the pH is not likely to lower at all, provided one does regular partial water changes to maintain the buffering capability, and provided the tank is not overstocked, etc.

    What is happening here is likely due to a fairly low GH/KH, or low enough not to be too permanent. As the organics accumulate, the water becomes more acidic due to the production of CO2 which forms carbonic acid.

    To the tap water pH, 7.6 to 7.8, first thing is how accurate this is. Tap water can contain a lot of dissolved CO2 which can lower the pH short-term, but once out-gassed the pH will revert to its normal for the water (GH and KH part of this). Letting tap water sit for 24 hours and then testing pH should give you an accurate reading. But let's assume 7.6 to 7.8 is accurate...this means the pH is going to teend to remain at this level, if the GH/KH buffering is sufficient. If not, then the pH will tend to lower over time due to the organics issue.

    There is an easy solution to the rift lake tank, and that is to use a calcareous substrate (aragonite sand, or one of the substrates specifically intended for rift lake fish). This will keep the GH, KH and pH up where it should be. There are also additives to do this, but these have to be used regularly and the substrate is generally a permanent fix.

    The community tanks are a different issue, depending upon the fish species. If soft water fish, letting the pH lower is better, and keep it there.
     
    • Informative Informative x 1
  3. Ivan Mann

    Ivan Mann New Member

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    Oh, boy, some research topics. I will get on this and get back, but it will take a couple of days. I just poured some water in a bucket. I'll compare today's reading with tomorrow's.

    I asked the question of the lead biologist on the fish tank project at the local university and he looked at me blankly and said they just adjusted pH every day with baking soda. This sounds like it will be the answer.
     
  4. Byron

    Byron Member

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    That is an extraordinary response from a "biologist." Do NOT use baking soda, it too is not permanent plus it harms fish long-term. Stanley Weitzman co-authored an article on water softening/buffering in TFH back in the 1980's, and recommended not using baking soda, and no one has ever countered his arguments.

    This is not difficult, it is easy, but one has to understand the chemistry or it won't make sense.
     
  5. Ivan Mann

    Ivan Mann New Member

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    ".. understand the chemistry...."

    To quote my youngest son, "You know, Dad, physics is a few simple concepts and equations that are easy to understand. Chemistry is a jumble of unrelated facts." To which I replied, "Son, I knew that before you were born."

    I'm off to research what GH, KH are and what my local levels are.
     
  6. Colin_T

    Colin_T Member

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    Besides what has been written by Byron, you could add some limestone rocks to the Rift Lake tank and it will help keep the pH up. It does the same as using the calcium based substrate. You can add shells or dead coral skeletons too because they are made from the same stuff (calcium carbonate).

    If you have very soft water, you can add some Rift Lake water conditioner, which consists primarily of calcium and magnesium chloride, and calcium and magnesium carbonates and bicarbonates. This stuff will raise the pH, GH and KH and the cichlids will do better, and the pH won't drop.

    --------------------------
    You should do water changes more often. I recommend doing a 75% water change and gravel cleaning the substrate every week. If you have water restrictions, then do it every 2 weeks. Doing bigger and more regular water changes, and gravel cleaning the substrate, will help keep the pH stable because there will be more KH in the water and less rotting organic matter using the KH.
    Make sure any new water is free of chlorine/ chloramine before it's added to the tank.

    There are a couple of other reasons to do big water changes.
    1) to reduce nutrients like ammonia, nitrite & nitrate.
    2) to dilute disease organisms in the water.

    Fish live in a soup of microscopic organisms including bacteria, fungus, viruses, protozoans, worms, flukes and various other things that make your skin crawl. Doing a big water change and gravel cleaning the substrate on a regular basis will dilute these organisms and reduce their numbers in the water, thus making it a safer and healthier environment for the fish.

    If you do a 25% water change each week you leave behind 75% of the bad stuff in the water.
    If you do a 50% water change each week you leave behind 50% of the bad stuff in the water.
    If you do a 75% water change each week you leave behind 25% of the bad stuff in the water.

    Imagine living in your house with no windows, doors, toilet, bathroom or anything. You eat and poop in the environment and have no clean air. Eventually you end up living in your own filth, which would probably be made worse by you throwing up due to the smell. You would get sick very quickly and probably die unless someone came to clean up regularly and open the place up to let in fresh air.

    Fish live in their own waste. Their tank and filter is full of fish poop. The water they breath is filtered through fish poop. Cleaning filters, gravel and doing big regular water changes, removes a lot of this poop and makes the environment cleaner and healthier for the fish.

    --------------------------
    Filters should be cleaned at least once a month and every 2 weeks is better. However, if the filter is less than 6 weeks old, don't clean it because you can get rid of the good bacteria and start the cycling process again.

    Wash filter media/ materials in a bucket of tank water and re-use them. The filter case and impellor assembly (magnet with plastic blades) can be rinsed under tap water and then set back up.
     
    #6 Colin_T, Aug 22, 2019
    Last edited: Aug 22, 2019
  7. Ivan Mann

    Ivan Mann New Member

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    I don't mean to be argumentative, which means I am going to be argumentative.

    Every single trotropi fish how-to says ever change more than 25%, unless there is a sickness issue and you are getting drugs out of the water, except one place that says 25-30%. Taking 75% out takes 75% of the bacteria and that doesn't sound right. I can go to 25% every week, pulling the gunk out of the gravel.

    I found a detailed chemical analysis of the water, which mentioned everything except KH and GH. It says total hardness is 76-140 and total alkalinity is 44-78. Does that tell anything? Tomorrow I can go by the pet store and get a test kit for each.

    Suppose a 25% change for the 20 gallon tank, that would be 5 gallons. Over the course of the week two gallons evaporated, so would I take out three and replace five? Take out five and replace seven? Take out 4.5 and replace 5? Okay, I am overthinking this 25% thing.
     
  8. Byron

    Byron Member

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    Bacteria are not removed by large water changes. Bacteria live on surfaces in the biofilm, and they are not that easy to dislodge. The vacuuming of the substrate during a water change will not dislodge many if any, and even rinsing filter media under the tap is not going to either dislodge them or kill them though the level of chloramine and the length of time might have a minor impact.

    Thinking related to partial water changes has changed substantively in recent years. A series of articles in TFH a few years ago demonstrated mathematically how a 10% partial water change every day was next to useless, while a 70% once a week was a major benefit. Yet the same volume was being changed under either method every seven days. Provided the parameters (GH, pH and temperature) are reasonably the same between the tank water and the source (tap) water, you cannot ever really change too much water. I have been doing changes of 60-70% every week for over a decade now, and I know the fish are better for it.

    Total hardness is GH. Alkalinity is the KH. But what is their unit of measure? I doubt this could be degrees GH, so it might be ppm or mg/l (these two are the same in effect), or if you are in the UK some other unit like Clarke.

    I wouldn't spend money for a test kit unless you want to, as you may only use it once. GH and KH does not change much in the aquarium (unless it is being specifically targeted), it is pH that can depending upon the former and other factors.

    Is the evaporation rate really that high? The tank should be covered to prevent this, for reasons I won't get into now. You need to be changing far more water though, as I and Colin have indicated.

    Jack Wattley used to write in his monthly column of discus breeders who perform two and three partial water changes of 90% of the tank water each time, every day. The fry grew much faster and developed much healthier. Nothing even compares to significant water changes when it comes to fish health. In their habitat, fish do not respirate in the same water from respiration to respiration. We cannot come close to this in an aquarium (unless we use flow-through water) but large regular water changes do make life much better for the fish. And this is what we should be really concerned about. :fish:
     
  9. seangee

    seangee Member

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    Assuming your readings are PPM your water is too soft for Malawi Cichlids. @Colin_T and @Byron have both proposed effective solutions to this. Your KH is fairly low. KH (alkalinity) buffers against drops in pH so it is notsurprising your pH drops over time. Ironically bigger water changes will actually improve this.

    The current view is that pH is irrelevant as long as it is stable. In my tanks I target GH and don't worry about pH - I don't even test it. My problem is the opposite to yours in that I have very hard water (suitable for those African Cichlids) and the fish I keep all need soft, or very soft water. Each of my tanks is different, depending on the needs of the fish in it, but GH is the only thing I adjust and let the pH settle where it will. Since these things are related my extremely soft water tank happens to be more acidic than the "middle of the road" tank.

    WRT larger changes I too change 75% every week in all of my tanks (even the shrimp tank). I have never heard anyone say their fish got sick because the water was too clean (borrowed from another member but I don't recall who). Byron is correct when he says the bacteria are not in the water column. According to Aqadvisor my South American tank is seriously overstocked (220% if I count the snails) and dangerously under-filtered (25%). Yet I have never seen an ammonia or nitrite reading other than 0. The only time I have had to treat this tank for anything in the 5 years it has been running was for worms which were introduced by new fish I added.

    FWIW I don't rely on Aqadvisor as a reliable source. I only checked my setups out of curiosity, but it does illustrate that I am not throwing 75% of my bacteria onto my lawn every week.
     
  10. Ivan Mann

    Ivan Mann New Member

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    I changed about 75% of the water in the tanks. Then I put Seachem Malawi lake salts into the cichlid tank, and then I put Malawi buffer in twice, both times following the directions on the jar.
    Today the GH/KH test kit arrived in the mail, and here is the current reading

    Cichlid tank KH took 17 drops for about 300 ppm, which is what it says is ideal. GH took 34 drops, which is way off the scale. PH is now 7.83.

    The community tanks were both 18 drops or a little more than 300 ppm for KH and for GH I stopped at 34, which is way, way off the scale. KH also seems to be high, trusting what the package insert says.

    So, I think the problem in both of them is GH. The package insert says to change water with deionized water, which might be difficult (i.e., expensive). Or, API Water Softener Pillow.

    Recommendations?
     
  11. Colin_T

    Colin_T Member

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    What fish are in the community tanks?
    You probably don't need to buffer the GH and KH as much in general community tanks and if you keep tetras, angelfish, Corydoras, loaches or rasboras, they prefer soft water with a GH below 150ppm.

    African Rift Lake cichlids need the hard water 300ppm, which is what you got with the Rift Lake conditioner.
     
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