How To Have Perfect Discus Water

Want perfect Discus water in your tank? Tired of fussing with chemicals and RO systems? Unless your backyard is the Amazon river you need to read this. Having perfect Discus water in your tank is easier than you think.

In this article we will cover some tips on how to have the best Discus water in your tank!

Do Not Use Chemicals

There is no reason to be messing with your current water via chemicals purchased online or the local fish store. Here is why, unless you are a trained chemist or run your tanks like laboratories, you will mess up or run out of chemicals. Then what? Let me tell you what will happen, the water in your tank will become unstable leading to, you guessed it, Discus death.

The only one solution you should be adding to your water is your favorite brand of chlorine/choloramine remover. That’s it! Chlorine and Chloramine are found in municipal water sources to kill bacterial growth. One other very bad thing it does is burn the gills of your Discus. That is why treating your water used for water changes with chlorine/chloramine remover is a must.

Separate Water Container

The ideal setup would have a separate container with enough water for 100% water change on stand by. This can be done easily by using a heavy duty plastic trash can which can be purchased at the local hardware store in different gallon sizes. Personally I keep several 45 gallon plastic trash cans filled with water for Discus.

When purchasing your trash can, don’t forget to buy the lid! This will come in handy when trying to keep the water temperature stable.

The trash can is either filled with an Tap/RO mix or straight Tap water. Inside the trash can I place the following in the water:

  • Titanium Heater – I set this to match the tank temperature so when the water is used there is not a huge fluctuation in temperature.
  • Powerhead – This is to circulate the water in the trash can. Without this the water would not be evenly heated.
  • Air Stone – A large air stone with a powerful air pump will not only make the water oxygen rich but will also quickly stabilize the water chemistry.
  • Chlorine/Chloramine Remover – Reading the lable on the bottle I introduce the required amount of remover per gallon of water.

So how do you get the water out of the trash can? If strong enough the same powerhead can be used or a stronger inline water pump can be used to take water from the trash can to your tank.

Stop Obsessing About Chemistry

Discus are resilient if and when raised with a good diet and kept in clean tanks. I have seen many hobbyist obsess over water chemistry to the point where they are more interested in water than Discus.

Enjoy your Discus and pay attention to their health. Discus can do great in many regions and in a variety of water mixtures. What Discus and most all living things cannot tolerate is a constant change in environment and the stress it produces.

By using harsh chemicals to replicate the impossible perfect water what you end up doing is sending your Discus to an early grave. If you want to remove particles, lower total dissolved solids (TDS) or other harmful substance use an RO System or water from a “Water Store”. Other than that keep your water treatment routine simple, clean and stable.

Questions For You

Do you keep water for water changes on stand-by?

Do you treat your water with chemicals?

Do you use and RO System?

16 thoughts on “How To Have Perfect Discus Water”

  1. I have a rain barrell, I live in a farely rural area. Can I use rain water for my discus? I haven’t started my aquarium yet. Tank is set up but no fish. Trying to learn all I can before I stock the tank. Anyones input will be appreciated.

  2. Hi Tom,

    I have never used rain water before but have heard of it being done. It would be a matter of collecting the water and testing it to make sure it could be used for Discus. If not I am sure you could collect it and run it through an RO filter to clean it up a bit.

    Hope this helps!

  3. I use a tap/ro mix for all my water changes and only have two tanks that are not bare bottom. One is a 55 gal. show tank in my dining room and the a 100 gal. show tank, in my living room. Personally gravel adds a lot more problems if you have a lot of tanks as I do. I move my Discus from show to breeding tanks as they pair off. This allow the couples privacy in a fish only room and I am able syphon off any debris after feeding ( a mini water change a couple of times per day) The importance of water changes (removing fish urine and poo) is essential to keeping healthy Discus. By the way my two show tanks are in high traffic areas, and thus are heavily planted, alllowing the Discus to some person security when they feel thay need it. There are other great benifits to planted tanks as well.

    Thanks again


  4. Rain water is fine, just run it through a canister filter with carbon and then add minerals like you would RO water.

  5. Is bottled can water good for Discus? I have a problem of NO3 in my tank, I did half of water change with good tap water, still My NO3 is 25 is it ok or should I need more water changes, Can some one guide me. Thanks.

  6. Sir, is there any precaution to avoid sunlight to the huge plastic drum which will be used to store stand- by ?. Is ro filter ideal? With regards NIKHIL.

  7. Im wanting to start a discus tank I have a 35gal hex and I set up with gravle and drift wood my water is from a deep well and ph is high and im reading thay like a low ph and need advice on giting it down and keeping it down with all the water changes all advice on water quality and what I should do will be grate thank you

    1. Joshua,

      Discus Generally prefer a lower PH, somewhere in the 6.0-7.0 range, however I have known people who have properly acclimated them during thier purchase/quarentine stage that have kept them with a higher PH with no problem. Where you may find a problem, is if you are planning to breed them. then you will definately want to lower your PH and Keep an eye on the conductivity of your water, looking for a hardness (GK of about 3) and conductivity of somewhere between 70-110. Hard water will prohibit proper fertalization of the eggs.
      Hope this helps.

  8. Hi. I have just purchased a four foot tank and would like to keep discus. I have an ro filter.
    A few years ago i kept discus in pure ro water and they were happy and healthy and i planned to do the same this time around until i heard that this is not a good idea.
    I am not sure what to do now. The water when i live is very hard. Would you recommend i mix ro water with tap water and if so to what ratio?
    Many thanks

  9. I do keep 2 large plastic buckets for ageing water and keep it aerated for about 5 to 7 days before i do a 40 to 50% water change once a week or sometimes 8 to 9 days.I do not keep heater in the ageing bucket as my tank is large about 5x2x2 feet so i switch offf the tank heater about 3 to 4 hours before a water change so the temp is about 29c from 33c.Then when i do the water change which is about 26c the teperature suddenly does not chang rapidly.I use an atman 1000 to pump water into tank which is bare bottom after removing the debris by siphoning water.After adding water i add a little ph buffer 7.0 from api product and aqua fresh coat for removing stress.Never used RO water as i keep normal common strains bred in india which are used to 7.0 to 8.0 ph and tds of about 200 to 230.I love to keep wild discus and importing it into india is almost not possible due to rigid customs and recently i received a mail from some lfs selling wild discus of 3 inch for about 75 US dollar a piece and once i get them i shall be seriously thinking of RO,peat balls,pellets,dim lights etc.Otherwise in my experience i had used chemicals like melafix etc and it only made fish more stressed and killed some.

  10. I am setting up a 300 ltr discus tank. I am currently experimenting with the water balance. I settled on 50/50 RO & filtered water giving a a nice ph of 7. But as soon as I aerate the water it drives out the CO2 and raises the ph to 8+. Therefore do people not aerate their their discus tank?


  11. I live in Thailand. I have 10 Discus in two 90 gallon aquariums including the water for the filters. I purchase pre filterd water and I am not sure of the filtering process. The water is in large 5 gallon white plastic bottels. The PH between 6.8 and 7.0. I never use additiives in the water to raise or lower the PH Value, minerals or salts.

    I have a second aquarium 90 gallons including the filter with 5 Discus. I am using tap water. The water is not treated in any form. I filter the water thru a singel stage filter 0.3 micron filter. PH is 8.3. The Discus have lived in this tank for 7 months. They were very small and currently 2 + inches with out any issues.

    Water tempretures in both tanks is will very between 28c to 29.5c. I do not need to use a heater to maintain the tempretures.

    Lighting is a singel 2 ft T 5 light I leave it on for 6 hours.

    Both tanks are bare bottom tanks. The tanks only have the 5 Discuss. I use trikel filters in each tank. 40 percent water changes every two days. I have 200 gallons of water storage and always keep the water circulating using a power head.

    Bare bottom tanks with out decor or plants.

    Amonia 0, Nitrate 0, Nitirte 0

    I clean the tank bottoms every night using a electric vacum.

    I feed a receipe of salmon, chicken heart or beef heart, peas, bananas, red lettuce, varius vitamins, garlic. Never use spinich this can cause digestive issues. The receipe is chopped togather to have the same consistancy as crunchy peanut butter. Never cooked always frozen, I make enough for one week.

    I feed the Discus small portions 3 times per day for 3 days then feed them twice a day. I never over feed the fish.

    The Discus were purchased directly from a Breeder in Bangkok. No Hormones injected. There PH was 7.8 at the time of purchase there water temps are 32c to 34c. Large breeding farm that has been breeding Discus for 18 years.

    Not to repremand any one. I have seen Discuss breed with success in PH water of 7.8.

    They do a 100 percent water change daily. My question is will the higher water tempretures and 100 percent daily water changes increase the motabilism of the fish so they can produce healthy fry?

    1. Hello Larry,
      I live in India, i am glad that you are successfully keeping your discus with a pH level of 8.3, because i am in the same situation my pH is almost the same. But in the planted tank the pH is little less ( 7.8) may be because of the plants and ada substrate. Almost every alternate days i change water in bare bottom tanks where the pH is 8.3 like you i dont believe in experimenting with chemicals for bringing down the pH level; earlier the water hardness use to be too much beyond 280 ppm in order to bring down the hardness i use to add RO water but since 2 months the tap water has gone soft and i don’t have add anymore RO water.
      Two of the discus fish paired up in my planted tank and laid eggs in the same water condition but unfortunately the female ate them away. The female did this twice; may be they were young since i have not bred discus my knowledge is limited. I took this pair and kept separately in a bare bottom tank almost 2 months over nothing has happened; they move around freely but there is no sign of spawning. I feed my fish with Omega super color flakes,NLS and Hikari discus bio gold. Thank you.

    2. Hi,

      I am staying in Thailand (Bangkok). Can anyone share me a good shop to buy good quality Discus fish?

      Many thanks in advance.


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