Making Waterchanges

Making Waterchanges


The Importance Of Regular Water Testing!
written by: Pete Fowles


I would like to tell you a story about the importance of regular water testing. Let me give you some background information on my tank and water parameters. My tank is 83 gallons and I do a water change 2-3 times per week of 30-40%. The fish I keep are Discus, Plecs and some acidophilic community fish. The tank is planted and is aquascaped with bogwood , rocks and pebbles. The filter is an internal design which is extremely suitable for this kind of tank and the design has been used in many tanks before this one. My water parameters are: ammonia 0, nitrite 0, nitrate < 30 ppm, 2 dKH, 10dGH and pH is usually 6-6.5.

As stated above, I was doing my usual water change of 40%. I took some water out to test, before doing a water change. As usual I refilled the tank and tested the water as normal, the readings were ammonia 0, nitrate 20 ppm, nitrite 0 and pH was 6. I looked at the reading and decided they were ok. I fed the fish and everything was fine, put out the lights and went to bed.

I got up the following morning and went downstairs to make breakfast etc. I decided to feed my fish and looked at the tank, to my horror the water was cloudy like milk but clear at the bottom about 10 cm ( 4 inches ) in height. I immediately checked the water and found that the ammonia was 15 ppm, the nitrite was 15 ppm, the nitrate was normal and the pH was at 6.5, so I did a 70% water change and the water cleared. I took a water sample to a friends house for testing to make sure my tests were ok, and this revealed that the nitrite was 15 ppm, the ammonia was 15 ppm and the pH was 4.5!!!!!!!!. I returned home to find that the water had clouded again so another 70% water change was done.
Whilst doing a water change I noticed that the water had a scum on the top of it, I took a sample to the local fish shop and asked advice. It was then that I found out that the local water authority flush the water system with lime every two weeks to I had not realized this because I was using a narrow range pH test kit( which I found out was faulty) then with the pH as low as it was , this caused a reduction in the filter bacteria therefore the lime killed off the remaining bacteria in the filter .A major filter crash had happened and I had lost quite a few good fish including half of a breeding pair of discus . I had to get my filter going again so I got some seeded sponge out of a friends filter and kept doing 70% water changes for 2 weeks. By this time I had lost quite a few more fish but the filter was going again and everything was ok .
I now know the problems which caused the filter to crash:

  1. The pH test kit I was using was faulty it read 6.5 whatever pH the water was.
  2. The water being so soft (<2dKH, 10dGH) had caused pH fluctuations due to the buffering capacity (2dKH) of the water( nil ).
  3. The lime added to the water under normal circumstances would have not caused any problems but because the filter bacteria were reduced ( due to low pH). it caused the filter to crash.

I hope that this information has been useful to you all and that you do not make the same mistakes as I did !!!!

Pete Fowles ( Ossypete)

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