eXact Micro7+ Water Tester

I bought an eXact Micro 7+ photometer for testing the pool water. I’ve since used it for testing and balancing rainwater and for my son’s aquarium. It’s my favourite tool.

I purchased the eXact Micro 7+ (eXact® Micro 7+ Standard Kit) after my first experience with balancing the pH in our new pool… The pool handover kit contained a simple colour strip tester that showed chlorine, bromine, pH and total alkalinity, and a separate test kit for copper levels. The pH came up as a soft orange, definitely on the low end of the colour comparison scale, so I went out and bought some pH buffer and threw in the recommended amount to lift the pH. And the copper test could have been interpreted any way – comparing a lightly coloured liquid with three printed colours (to indicate high, ok, low levels) of a slightly different shade is complete guesswork. I guessed it was OK, because I wanted it to be OK. After retesting the pH and finding that adding the pH buffer had caused no apparent change in the test colour, I took a sample to a pool shop and had it tested properly. After waiting 15 minutes for a lady who was explaining her acid problems in detail while I was in a hurry to get to work, the test results were surprising – pH was far too high and copper was low.

My next step was to look on the Internet for a more reliable tester. The next step up is a photometer which can read the colours of a paper test strip electronically; at around $100, these look like a reasonably attractive proposition buy I was already suspicious of paper tests. On the expensive end, in the $1000+ range, are colorimeters which measure the colour of the water after reaction with a liquid reagent.

Then I found, in the more reasonable price range of $200-$350 is the eXact Micro 7+. It uses a reagent on paper strips which are dipped into a cell containing the test water sample, where the Micro 7+ can then read the colour. Coming with 7 basic tests (pH, free chlorine (DPD-1), total chlorine (DPD-3), copper, total alkalinity, calcium hardness and cyanuric acid) with the option to purchase other reagents to test over 30 other parameters (salt, iron, manganese, nitrate, nitrite, etc), this is a very versatile kit. It gives an actual numerical readout – like pH 7.6, for example, so there’s no uncertainty in the reported value. I thought it represented excellent value for money and that has shown to be true.

Of course I used the eXact Micro 7+ kit first to balance the pool water, and it has been excellent for that.

Then I tested the rainwater. The pH was acidic off the scale and copper was above healthy levels! Basically the eXact Micro 7+ alerted us that our rainwater was eating our copper pipes. So I tested each rainwater tank individually (we have 3 concrete tanks). The first was acidic, and the other two were highly alkaline! Rainwater is naturally acidic, at pH 5.5 – 6.5, and coupled with low hardness this can make it highly corrosive. But concrete is naturally alkaline, at least until the alkalinity has leached out, so our two newer tanks were showing a high pH. By mixing the water from the tanks I was able to bring the pH into line and the copper levels have reduced accordingly.


You can buy the eXact Micro 7+ Photometer and reagents online at FiltersFast.com.