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All Photo by Ricardo Cervantes 2004

Water, It’s in the MIX
Discus owners must understand the following about keeping discus.
The five most important things for Discus are;

1. Good Quality Water
2. Good Quality Food
3. Good Quality Water
4. Good Quality Food
and, Finally again………5. GOOD QUALITY WATER.

Notice that good quality water is constantly there again and again.
Discus are really not that difficult to keep as long as you understand and provide their basic needs. Good Quality water basically means water that is free of toxins that will inhibit your discus to thrive and that the water is free of chlorine, ammonia, phosphates, nitrates and overall impurities. The water hardness and pH values you keep your discus in will depend on what you want your discus to do. If your intent is on breeding Adult Discus then soft water will be the way to go for the breeding pairs. The fry however will have to be gradually moved into harder water after they are removed from their parents so that the mineral content in hard water will help your young discus grow and develop strong bones. If you are just keeping discus for their beauty, then they will acclimate to just about anything from soft to hard water and PH from 5 thru 7.5+.

Water Hardness:

How do you get the right hardness if your water if it is either too hard or soft?
Most of us unfortunately live in areas where the water is too hard to breed the discus without “messing” with the water some how. Here in Florida, where I live, the water is considered very hard. Without going into a really big discussion, water hardness generally deals with “how much mineral content” is in your water.
The “pure water” contains no mineral content so it is considered to have a TDS (Total Dissolved Solids) of Zero.

0 - 50ppm Very Soft
50 - 100ppm Soft
100 - 200ppm Moderately Hard
200 - 300ppm Hard
300+ Very Hard

There are two ways to talk about hardness, carbonate hardness (KH) and general hardness (GH). Carbonate hardness is caused by the amount of carbonate/bicarbonate ions. This is important because it gives water the ability to resist water PH changes also known as the “Buffering Capacity” of water. Therefore one could say KH and PH are inter-related.
General hardness on the other hand is the dissolved solids to include metal ions in the water mostly magnesium and calcium.

Ok enough of the Mumbo Jumbo. What you really want to know is just how do I keep my discus in it Right? OK, here we go!

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If you need to soften your already hard water you are going to need a method of obtaining water that is of less TDS than your water so you can mix or “cut” your water.
There are various methods out there but what works best for me is a Reverse Osmosis Unit (R.O.Unit). There are many on the market most are basically the same. Make sure however, you get one with a Thin Film Membrane, you will get better results. I could bore you again with explaining how this baby works but I won’t (Ed: we’ll leave that for another article). In a nut shell, the R.O.Unit takes hard water from your tap and gives you very, very soft water as the output. My water goes in at a hardness TDS of 320ppm (parts per million) and it produces an output TDS of 5ppm, very, very soft water. Also keep in mind that your waters hardness will determine the life of your R.O. filters’s membrane; I currently replace mine about every two years.

The Mix:

Now that I have soft water (usually in a 55 gallon rubber type trash can) I need to mix it back to a useable level for my discus because water that is that soft can injure most tropical fish for LACK of minerals in the water that the fish need. Two items that you are going to need if you are to save yourself time is an electronic TDS meter and a PH meter. Most are readily available at your local fish store or thru the internet. Cost will vary but most will range from 50 to 75 dollars each.

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I age my water for a period of 3 to 6 days in plastic barrels. At this point I mix some RO water with plain de-chlorinated Tap water until I get the TDS level I want. I normally target of 40 to 50ppm TDS for breeding Discus pairs and 150 to 175ppm TDS for growing young. The number doesn’t have to be exact, this isn’t rocket science. This is where “close” is ok!

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I then add another item to my water aging barrels, a few Indian Almond leaves.
Leaves from the Indian Almond Tree (Terminalia catappat). The dried leaves from this tree are used extensively in the far east by tropical fish farmers. The leaves contain tannins (s. a. punicalin, punicalagin and tercatein) which will gradually lower your waters PH. I use one leave per 10 gallons of water. These usually last for about 2 to 3 weeks at which time I will replace with new ones. Additionally the tropical almond leaves have antibacterial properties and seems to really help with any injuries and disease. I also believe the tannins also have a calming effect on the fish. Once the leaves are soaked in the water for a few days they will turn the water a light tea color. Don’t worry about this it is not a problem.

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Indian Almond Tree (Terminalia catappat)

Check your water often for TDS and pH and don’t worry about it being the exact value all the time, slight variations are ok, +/- 10% is just fine. Discus are very tolerant of pH and hardness values as long as they are in line with what you are trying to achieve and any major changes are done gradually.

Now that you have aged and “treated” your water, don’t just let it sit there, Use it! Do water changes, then do water changes, and more water changes. Discus really thrive in clean water. The cleaner the better and it really doesn’t much matter the hardness or the pH depending on your reason for keeping them.

Make no mistake about it, water is the most important item in keeping Discus, next to food of course.

Good quality water and good food make for Healthy Discus.