I've always used RO water. However, I've always had a problem getting CA and Alk to decent levels and have suspected that it's because of the water being a bit too pure. I've been considering switching to tap water but I'm concerned because Edmonton uses chloramine.
Anyhow, today I did a test. I filled two buckets, one with a gallon of tap water and one with a gallon of RO. I did a chlorine test on both using an Azoo test kit. The tap water as expected was at the max end of the chart for chlorine (around 0.1 mg/l) and the RO had absolutely no detectable chlorine. Then I dechlorinated the tap water using a product by Hagen called ChlorXchange. It says clearly on the package that it is a "Chlorine and chloramine remover for fresh and saltwater use". I then tested the tap water again. As expected the chlorine was pretty much undetectable.
Now things get interesting. Supposedly when you dechlorinate tap water that had chloramine in it, you eliminate the chlorine but you liberate the ammonia molecules from the chloramine. So I tested for ammonia using a Fastest kit. The results for the dechlorinated tap water were not good. The ammonia was at the highest end of the scale at 0.8 mg/l. In order to verify that the kit was working right I also tested the RO water. No detectable ammonia.
The question is, is this level of ammonia dangerous when only doing a partial water change? Does the filtration system suck it up fast enough that it's not a problem? Is it possibly a false reading? (supposedly when using Ammo-lok to remove ammonia, people still read ammonia in the tank but it's "inert" and harmless. Perhaps this ChlorXchange product also locks up the ammonia in some way so that it's safe). Needless to say I'm nervous about switching to tap water. Has anyone else in Edmonton or Calgary done this type of test?
For those who are interested in the CA and Alk situation, I also went on to test that...
I let both buckets sit till they reached room temperature and then I added IO salt mix. I matched salinity in both buckets to exactly 1.025. I tested for calcium first using a Salifert kit with the high accuracy method. The tap water mix tested at 420 ppm. That's where I'd like to see it. The RO mix on the other hand, tested at 340 ppm, which explains why I have to keep at the additives to get the levels where I want them (400 to 450).
Then I tested both samples for alkalinity using a Fastest kit and the high accuracy titration method. The tap water tested at about 4.5 meq/l. That's a bit high but allowing for possible inaccuracy of the test kit, and considering that the water change will be replacing some of the "used up" alkalinity in the aquarium, its not a bad level. The RO mix came out at a dismal 2.75 meq/l. Again, this explains why I have to put a lot of additives and keep a steady Kalkwasser drip to get the levels where I like them (3.5 to 4.0).
I'd really like to switch to using tap water so that I would use less additives. Even the Seachem Kalkwasser that I use says to add 1 teaspoon for every gallon of water, but if using filtered water then you need to add 2 teaspoons per gallon. I'm using it up twice as fast as I would if I were on tap water. It galls me to think that each time a do a partial water change, I'm actually REMOVING some of the calcium and alkalinity, and then I have to bring the levels back up using expensive additives.
The chloramine/ammonia situation makes me nervous. I'd be interested to hear from anyone using tap water in Edmonton. Have you ever done this type of test? If you've tested your dechlorinated water for ammonia but couldn't detect any, what type of dechlorinator are you using? Do you have any problems with algea as a result of using unfiltered tapwater?
thx.
Jack
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