RO water for Discus Tank

Discussion in 'Technical' started by keith1964, Feb 28, 2011.

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  1. keith1964

    keith1964 Keith

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    Dear Professor

    I initially set-up my Discus Tank with normal tap water but our ph here Mitchell's Plain Cape Town is 8. I used the following products Kent minus and Seachem Discus Buffer to keep at 6.5. Are these the same products that I am using. I bought now 50L of RO water to do my next water change do I still continue using these products like Seachem Prime; Stability & Buffer when prepare my water for my weekly maintenance.

    Kind regards
    Keith
     
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  3. Singularity

    Singularity

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    keith you need to check the hardness of your tap water before you use RO water.
     
  4. OP
    keith1964

    keith1964 Keith

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    How does one go about tested the hardness, I have a kh test kit. I tested after 2 drops of agent it turn from blue to light yellow. Do I need to increase my hardness and how do I go about it?
     
  5. Singularity

    Singularity

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    that is soft, so no need to use RO water. Have you tried to let the water stand for a couple of days and then testing the ph again ? (getting accurate ph readings from soft water is difficult, could be that you are just getting false readings, if the fish look stressed it could be because of an unstable ph which was caused by the buffers that you used. Best is to get a 200L container, fill it up with water a week before you are planning to do a water change, get a 2000L/ph powerhead with venturi to create movement and aerate the water at the same time. Get a cheap 300w heater to heat the water in the container to tank temprature a day or two before you do the water change. Get some silicone tubing that will reach from your container to your tank. Once you have syphoned out the tank water that needs to be changed, attach the silicone tubing to the powerhead nozzle and use the powerhead to pump water back to the tank from your container. The flow will be slow, but this is good, gives the fish some time to adjust to any changes in water parameters of the new water)
    Everyone from the cape seem to have no issues with their water from the tap for discus tanks.
     
  6. Dirk

    Dirk Dwarf Catfish

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    Keith, Singu is perfectly correct, he means you need to measure your general hardness and carbonate hardness. You have only measured KH, and I would expect the carbonate hardness to be very low, but you need to measure your GH and I would expect that this could be a little higher, but not much more than 1 GH.

    There is a general misunderstanding that if your pH is high, say 8, your water MUST have a high hardness, but this is not correct, you can increase the pH without increasing hardness by addition of a tiny amount of caustic soda or a smaller amount of lime and this is often done by municipalities in the Western Cape so stop erosion of cement pipes (say from Voelvlei to Cape Town). However, this does not mean that you need RO water as a matter of fact I would view the use of RO water as completely unnecessary in the bigger Cape Town area. I am only too happy with my tapwater which has a pH of 7.5, when I do water changes in my aquaria, in which the pH tends to drop all the time. I fight a constant battle to keep the pH from dropping below 4.5 using bicarbonate of soda in spite of the water from the tap having a pH of 4.5. The acidification is the result of the production of nitrate in discus tanks which results from strong feeding.

    So, forget about RO, save your money for other equipment.

    Kind regards,

    Dirk
     
  7. Dirk

    Dirk Dwarf Catfish

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    My reply has now arrived after Singu sent his reply and you can see that we are saying basically the same thing.
     
  8. Marco

    Marco Retired Moderator

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    Hi keith,

    Two drops means you have a kh value of between 1-2dh. Dont alter it, its perfect. Dont use RO water, this will just lower the kh value to zero dh which due to biological acidification will at some stage result in a ph crash, and the death of your fish.

    Just leave that ph as is! Softness of water is more important than the perfect ph. Just watch it, it will start coming down and eventually you'll struggle to keep it stable. Most discus keepers dream of the water you have!

    If you dont trust me, wait until Prof. Dirk answer's you before you put ANY chemical in the water!
     
  9. Marco

    Marco Retired Moderator

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    and so did my reply...haha
     
  10. Dirk

    Dirk Dwarf Catfish

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    So now you have heard the same story from the third person keeping discus on this forum.....
     
  11. OP
    keith1964

    keith1964 Keith

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    Hi Marco

    I just did a RO water change this evening, my ph 6.5 and my kh value was 1-2dh. My tap water ph8.8 which I had just measure now with my electronic ph reader, i calibrated this evening. So i reckon that our tap water ph is high.

    How would you go about if your tap water has this ph reading? My tank ph has been at 6.5 for almost 3 weeks before I bought my discus. I am feeding them a variety of foods including frozens and pallets. They are now 1 week in my tank, very active chasing one another and greedy.
     
  12. OP
    keith1964

    keith1964 Keith

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    Before i do my water change I will fill my 50L container with a large airstone for 2 days and then a heater on the second day when i do my water change. I was getting confused with all the different opinions I browsed over the internet and various forums. Some says that RO water is good but on the other hand it is not so good. I live in Mitchell's Plain and our ph differs from other areas. Our ph had been over 8 for sometime since I was keeping Tanganyikan Cichlids.
     
  13. Marco

    Marco Retired Moderator

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    keith,

    First you need to understand the relation between ph and kh. Kh is an indication of the dissolved carbonate (carbonate hardness) in the water. This acts as a buffer preventing ph from going up or down. The higher the kh, the stronger the buffer. Up to, I'd say 4kh would be considered low kh value, with over 10 being very high. Now as Prof explained, over time, due to the nitrates in your tank water, the ph of the water will be affected (go down) unless properly buffered. If you have water with a kh value below 2dh, this can happen suddenly, and very unexpectedly. Now lets say you ph goes from 7 to 5.5, in a matter of hrs, this will result in fish deaths as it is effectively 150 times more acidic (ph scale 1' = 100). Adding RO water with a kh of 0 will thus effectively lower your kh which puts you at more risk.

    Dont stress about ph too much, rather aim to keep it at stable as possible.

    I live in PTA. Our water is way different to yours. (ph7.6-7.8, +-kh 7dh +-gh10dh) I use a 80/20 RO/TAP mix in breeding tanks, and in other 'grow out' tanks I use only tap, filtered through peat until kh is at 3dh. Ph? I couldnt tell you, and thats an honest answer. Last when I checked about 6.8 In time I have gotten to know my water, fish and setup. I take a look at the fish, colour, behaviour and the way they react to me, and I know what is up with the water. Though I follow a 2 x weekly Water change regime of 30% per change, I easily do a third or bigger if it 'looks' nescessary. I might sound like a 'care free' approach, its not. I just spend a great deal of time with my fish, and did the tests in the past, I dont need to now. Sort of like changing gears when driving. When you start you 'look' at the gear lever, couple of weeks later you dont, you just 'know' where to go.

    Hope it helps?
     
  14. Singularity

    Singularity

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    RO water can be very useful, for instance if you have very hard tap water, RO water can be mixed with the tap water to soften it (i used 2 thirds RO water and 1 third tap water, because we have extremely hard water out of tap). It can also be used to get certain species, which require extremely soft water to breed, to breed.

    Dont try to fix something that isn`t broken, if your fish look happy and they are eating well, just keep on doing what you are doing, things tend to go wrong when you start to fiddle with it. Also, dont overcomplicate things, keep it as simple as possible.
     
  15. OP
    keith1964

    keith1964 Keith

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    Hi Marco
    This morning I mixed 1 teaspoon of bicarbonate sodium to 1 liter of tap water and added to my can add again tonite or is there a product that I can purchase. So when I do my next water change must I add bicarb to it as our tap water has a low kh.
     
  16. OP
    keith1964

    keith1964 Keith

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    Hi Marco when I had my tanganyikan tank I used a alkalinity & carbon buffer from Seachem and tank remained stable at about 4 - 5 kh
     
  17. Dirk

    Dirk Dwarf Catfish

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    HI Keith,

    What sort of a "pH reader" do you have? When I hear this term used, I get nervous, because it generally means that someone has a cheap handheld pH meter which cannot measure pH accurately in soft water, for this you need a laboratory type pH meter with a high quality electrode. These pH readers are unable to measure lower pH accurately and falsely give a too high reading. The calibration also does not guarantee that the measurement is correct, because the calibration fluid is in a harder solution.

    Your pH will tend to drop once you start feeding your discus. You need to do your homework on the processes that cause this, read a good book on the topic. For feeding discus, I would advise that you look at the sticky thread on my "Ask the Professor" subforum.

    Kind regards,

    Dirk
     

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