Is reverse osmosis needed for a discus tank?

**gustavo85** · 02-14-2012, 2:35 PM

Hi! I'm looking to start on a new journey with discus but I've read in some places that reverse osmosis is highly recommended. However, I don't seem to understand how this truly works and find it a bit complicated. What do you guys think? What would you guys recommend? Thanks!

**wesleydnunder** · 02-14-2012, 3:27 PM

Reverse osmosis removes dissolved solids from the water. Where discus come from the TDS, or Total Dissolved Solids is very low, usually in the order of 50 to 75 ppm. Dissolved solids are the salts and metals dissolved in the water (along with some other compounds). Our tapwater is typically high in tds, sometimes up to 700 ppm or higher. You can test your water to get an accurate gauge of its TDS.

We separate these dissolved solids into two basic categories for our hobbyist purposes; KH and GH. GH is the water's general hardness, typically a measure of calcium and magnesium ions. KH is the water's alkalinity, it's buffering capacity, it's ability to neutralize acids and maintain steady ph.

The streams, rivers and lakes where discus originate have as mentioned a typically low TDS. The water also usually has a low ph as well. The low ph is maintained by the fact that the water is filtered through often several meters of leaf litter which acidifies it. It can stay acidic because the KH, ability to neutralize an acid, is very low.

The use of RO water for discus allows us to attempt to duplicate the low GH and KH of the native waters. The RO is either reintroduced with small amounts of TDS through the addition of discus preparations or can be mixed with varying amounts of tapwater to bring TDS up to some minimum safe level (you never want to try to keep discus in straight RO). The resultant water can then be filtered through peat to acidify it.

Wild discus do best in water that is closer to their home water in makeup. Domestic discus can be safely housed in most tapwater without use of RO. Juvenile discus grow better with a higher TDS.

Mark

**gustavo85** · 02-14-2012, 7:46 PM

Originally Posted by wesleydnunder

Wild discus do best in water that is closer to their home water in makeup. Domestic discus can be safely housed in most tapwater without use of RO. Juvenile discus grow better with a higher TDS.

Mark

So, what I guess from this is don't bother? I do not plan on having wild discus. I will however ask to the one that sells me the discus if he uses RO to make sure. But I don't want to spend the money unless it's truly necessary.

**wesleydnunder** · 02-15-2012, 7:58 AM

Originally Posted by gustavo85

So, what I guess from this is don't bother? I do not plan on having wild discus. I will however ask to the one that sells me the discus if he uses RO to make sure. But I don't want to spend the money unless it's truly necessary.

Checking with the breeder about his water is a good idea. It'll give you a better idea of what you may need to do to your water to be successful with his fish. Know your own tapwater parameters. You may be perfectly fine with using just your tapwater for discus.

Mark