Hi all,
Yeah but all this chatter about possible interference re aquarium water testing - what about urine testing 😉 ... those multitest strips work surprisingly well
They do, but it is back to the sea water analogy, you have a salty solution with a known pH and high nitrogen (urea) levels.
I looked at the chemistry behind each test kit method, noted the interfering compounds etc - I'm far from convinced that they are so significant & frequent as to invalidate "most" test kits ...
It really depends on what you are testing for, nitrate (NO3-), is always going to be problematic because it is a monovalent anion. There is a review of test strips (in agriculture) <"
here">.
I rarely test these days, but do recommend novice aquarists "test" - if they get results A +/- a, then suddenly result Z, there's something that needs investigating ... people can't bring their aquaria into the shops, but they can bring water samples ... assign something a name & number & it's a more level playing field for discussion than qualitative observations - especially with someone that has limited knowledge of fish behaviour, appearance etc
I'd agree with this, anything that identifies sudden changes is really useful, but I'm very dubious that people are going to get meaningful results from their LFS in the UK. They may do in the Netherlands, Sweden or Germany etc. where the hobby is more advanced.
I'm not anti-testing, quite the opposite, I'd really like to know all the parameters for the aquariums, and it was the difficulties in getting repeatable results that first led me to looking at other methods for estimating water quality. The only dip meter, or test kit, that I could find that gave repeatable results over the whole range of water conditions, without constant re-calibration or sample preparation etc, was a conductivity meter. Conductivity isn't the measurement you would like, but you can use it to get a datum for your water.
If you keep non-planted aquariums water testing is much more relevant, mainly because you don't have plants as a bio-indicator of water quality.
In commercial horticulture, even though they can now pretty accurately quantify the physio-chemical attributes of any novel media, growth trials in controlled conditions are still used to assess media suitability. Final decisions are made based on plant growth, colour, time to flowering, flower production etc .
The same applies to waste water treatment, a range of bioassay organisms are used to quantify "clean" water quality before that water is discharged back into water courses etc. Among the bioassay organisms used are "Duck-weeds" of the genus
Lemna. In the
<"Lemna bioassay">, plant mortality, leaf colour and rate of increase are used as indicators of nutrient and pollution status.
In water quality testing in streams and lakes etc. you use a combination of <"
5 day BOD"> test and a
<"biotic index"> to quantify water quality. If you have chemical and physical parameters (substrate type, pH, geographical region etc) for your water courses you can use probability to estimate whether your invertebrate sample differs significantly from the predicted value. If you have a much lower score on the biotic index than <"
the prediction"> you have an indication that a pollution event has occurred.
Unfortunately we can't use either BOD test or biotic index for the aquarium, but we can use the health of a floating plant (floating to remove CO2 from the equation) as an indication of nutrient status. Sadly a lot of people use fish with high demands on water quality as a proxy biotic index, and rapidly kill off Hill-stream Loaches, large rheophilic plecs, Chocolate Gourami,
Tropheus etc.
I started suggesting using the <"
Duckweed Index"> because plants are the single largest factor in maintaining water quality, and it gave people an easy visual guide to tank health. It is a "
win, win" situation.
cheers Darrel