Reddit mentions of Oakton EcoTestr pH 2 Waterproof pH Tester

If you read enough reviews about any pH meter you'll find there are flaws in all the reasonably priced ones, eventually. I've had this Oaktron for 2 years. It worked fantastically for about 1.5yrs then I needed to calibrate almost every time I used it. Now it won't even calibrate anymore. It was about $42 when I bought it and the price has gone up. I won't buy another for how much it gets used.

I considered buying a Milwaukee or Hannah but the $100-$170 models have some serious poor reviews for valid reasons. These ones tend to have replaceable electrode but from what I understand they are costly and don't always mean long term life. If I were a pro brewer I wouldn't hesitate to buy a scientific pH meter cost several hundred but as a homebrewer (who knows the water he's working with and approximate adjustments for different color/style beers) I couldn't justify it.

So I went with this $30 2 pack which so far has some pretty great reviews and if the two only last me 3 years I'm ahead of the last one.

I've used this one for about 3 years now and rarely needs calibration and very well built/sturdy https://www.amazon.com/Oakton-EcoTestr-Waterproof-Tester-Range/dp/B01MRR61TI/ref=sr_1_10?s=industrial&ie=UTF8&qid=1481303425&sr=1-10&keywords=ph+meter

I use this bad boy, which is a little above your price range, but I love him.

Before that, I used this pH meter pen, which was pretty good. It was kind of a pain to calibrate, but it was very accurate once calibrated.

Well, the pH meter I have is this one but I really doubt you need one that nice. Plenty of people use the $20 ones. Basically the same with TDS meters, nothing too expensive is necessary for our basic purposes. When I say my pH was bouncing around I actually mean a couple things, #1 I wasn’t properly treating the water so after a few minutes the pH in a bucket of new water would come back up, but more importantly #2 my kH was a little high, and my pH was too, so not enough CO2 was staying in the water. Look up “tom barr kh ph co2 chart”, he has a good explanation.

Seems like your light is plenty bright! My lord… ya I guess that 18” makes sense.

Interesting info about your nitrates! I guess a good idea to do WCs then. It would seem to me that means your plants aren’t eating it up, which means something is off- since your light and nutrients are presumably high enough via IE dosing, it seems all that’s left is CO2, barring some strange factor like a poison or something. That or something is contributing excess nitrogen (soil? I have this and used some floating plants to pull excess out). Oh also I guess some people say the API test kit isn’t accurate…not sure if that’s true.

One other thing I noticed, since there are multiple factors we are changing, it can be hard to tell what works and doesn’t. Plants also take time to react. So you shouldn’t look at issues as a series of failures, rather that you are making a series of corrections but the whole system doesn’t work until you figure out every part. So it sounds like you’ve been making progress, by all rights you are close to having things run perfectly. Also, if you only have one algae that’s like 10x less than I did 6 months ago.