Water Testing Equipment


New Member
Aug 31, 2020
Auckland, New Zealand
Hi Y'all,

I have been keeping fish since the mid 1970s. Low tech (non-CO2) planted tanks have always been my thing. This worked really well for me when living in Ohio. Now I live in New Zealand and have a 300x60x60 (10'x2'x2') mbuna tank that has been set up for 2 years and the plants are not growing, plus I am getting tired of cichids.

I have decided to make a radical change, start with CO2, and try my hand at breeding tetras.

I have done a bit of reading, and have lots of questions. The first one is, what testing equipment do I need?

For my cichlid tanks that has never been as issue once the tank had been cycled, ie ammonia and nitrite zero, nitrate barely detectable. I have automatic drip water change systems on my tanks, which keeps nitrate low. I am thinking in my current setup it might be too low, because the fish are small.

Anyway, I bought a cheap pH meter and have an API starter test kit. What else do I need? KH, GH, anything else? Are the API tests the way to go or is there an easier/better method?

Many thanks!

Picture of one of my old low tech planted tanks just to show off! :)



Aug 23, 2018
Some of these can be considered over-the-top and some are not critical, but they are a complete list of my personal favorites:

NO3: Salifert (freshwater or saltwater versions - good precision in the 5-20 ppm range and easy to use) and Sera (good for clear separation between 10 and 25 ppm)
PO4: Hanna low-range colorimeter (highest precision) or Salifert. Note: for both, above 3ppm, dilute 5:1 with RO or distilled water, then multiply result by 5. API kit is good above 3ppm
K: Salifert (good precision up to, at least, 50ppm), JBL is acceptable
GH/KH: API or Sera (modified: use 5x the water, then divide results by 5)
KH: Hanna colorimeter (used mainly at very low KH levels, such as <1 dKH and where higher precision for CO2 determination is desired) or API (modified: use 5x the water, then divide results by 5)
Ca: API (modified: 50 ml sample water, add 20 drops of reagent #1, each drop of reagent #2 = 2ppm)
Mg: easily derived from the formula: (GH ppm – 2.5 x Ca ppm) / 4.1
Iron: Nutrafin (may be labeled under the Fluval name)
Total ammonia: Salifert
pH: use a pen, such as; Dr.Meter (0.01 resolution), Apera PH20 or Hanna
TDS: use a pen

You can easily use the least expensive options and/or not perform the indicated modifications and still have reliable results. Depending upon how deep you want to get, it is always a good idea to calibrate all of your test kits.

At a minimum, I would recommend testing for NO3, PO4, GH, KH and pH. Never use test strips.
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