Water Quality - part 2, the mains supply

It's true to say the water that comes out of the tap is highly purified, free of micro-organisms and ideal for consumption……..by human beings. Where fish are concerned though it's a different matter. To get the water fit for humans the water companies have to deliberately add various chemicals (Chlorine and/or Chloramine) to ensure that any pathogenic micro-organisms ie stuff that would make you sick are eradicated or minimised. Nothing wrong with that, personally I'm happy not getting sick every time I brush my teeth. In addition though there's all sorts of stuff in tap water that humans don't seem to be that bothered by (Nitrates, phosphates, carbonates, low level heavy metals etc etc). All of the above (and I'm sure other factors) can be harmful to fish - especially to sensitive species like Discus. So somehow the "contaminants" in the water supply need to be dealt with before we ask our precious fish to swim around in it 24 hours a day. Some of them can be dealt with using additives which eliminate the chlorine or chloramine - there are many on the market. Alternatively we can physically remove the contaminants using Reverse Osmosis type technology which will essentially remove >99% of non-H2O molecules through ultra fine flitration, although there are approaches that are less aggressive. The approach that I need to take should be driven by the parameters of the water which I get from the tap…which are as follows: pH 7.1, GH 18, KH 14, Nitrate 20mg/ml, phosphate 1.75mg/ml. Of course there'll be lots of other stuff in the there that I don't have the ability to measure. Now actually, that isn't too bad - and talking to the shop where I'll probably source my Discus (http://www.devotedly-discus.co.uk) they advise that these overall parameters are fine for the Discus they can supply. I still need to get rid of that chlorine, sediment and heavy metals though. So my plan is to use the HMA filtration approach. I understand this to be something of a half-way house to full RO filtration. The advantages are that it's a little cheaper to run but crucially I don't think it requires further post purification supplementation with additives - this has to be done with full RO water as this is SO pure that the fish can't survive in it - apart from anything the water is highly unbuffered and will be subject to wide pH fluctuations. Bottom line is: HMA should make the water changes a little easier, which will be important as they'll need to be regular and large. So, to cut a long story short….On Saturday we’re going to go and visit Devotedly-discus, where we can have a look at the fish (!!!!) and also pick up an HMA filter set up which will be the way I purify the tap water before it goes in the tank. I'll post about this after Saturday's visit - it should be very interesting!