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View Full Version : RO units-are they essential?



shawn barker
Thu Apr 05, 2007, 12:01 PM
I've been using an RO unit for a couple of years now. I use a ratio of about 2:1 of RO mixed with tap for my water changes and have found that my water remains nice and stable and the fish seem fine with this.

It's time to replace the RO membrane as the TDS is starting to climb and the time it takes to filter the water is reduced from about 4-5 hours for 25l to about 90 minutes to do the same and then flood the kitchen floor!

My water parameters from the tap are (by the way I'm in SE England):

pH - 7.6
Nitrate - 5 mg/L
Ammonia - 0
Nitrite - 0
Phosphate - 0.25 mg/L
kH - 50ppm
gH - 120ppm
Iron - 0
Iron (chelated) 0
Calcium - 40 mg/L

All test are carried out using the Hagen Nutrafin master test kit (liquid drops and colour change charts so any dodgy readings are probably down to my dodgy eyes comparing the colours :shock: )

Which brings me onto my question,

I've read a bit about HMA and CBR units but not sure how they work in comparison to an RO unit, other than they don't waste water to the extent of an RO unit, therefore was wondering if one of these units would be suitable for the needs of my fish or am I better staying with the tried and tested RO units? Like many people I'm concerned with the amount of water that is wasted with an RO unit hence my curiosity about possible alternatives.