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:
- The pH test kit I was using was faulty it read 6.5 whatever pH the
- The water being so soft (<2dKH, 10dGH) had caused pH fluctuations
due to the buffering capacity (2dKH) of the water( nil ).
- 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)