PH meter decision

[JTL]

I have been reading about the various PH meters and I am not sure what to do. I can buy a new Pinpoint for about $80 or I can add the SL1 module to my RKL and buy a probe for it at a cost of $120 or I can just by a cheap pocket Hanna or Milwaukee for under $30. Seems to me they all need to have the probe replaced after a year or so and it would be cheaper to just to replace the Hanna since a new Pinpoint probe is $50. Does the accuracy vary much? Oh, I guess another option is to use a test kit for under $10.

[Frogmanx82]

If you know of a test kit where the color of the dye matches the color on the chart let me know. I have given up on the drops for any kind of accurate reading.

I went with the $20 Milwaulkee 600. About the same as a test kit, so I can buy a new one next year if it goes bad. My saltwater mix is pretty consistent at 8.3, or I mix a bit of baking soda in rodi water for a solid 8.2 for calibration. I'm finding the pH of rodi water to be extremely variable, is that normal? I would have thought 7 but then again, with no buffer at all, it doesn't take much to move it.

[HighlandReefer]

The Pinpoint meter at around $80 will provide accuracy down to 0.00. Many of the other meters will only go down to 0.0. The dual calibration feature is much more dependable then single calibrating meters.

[HighlandReefer]

pH meters will not provide accurate results when you use them in rodi water.

Randy goes into the details in the article:

Reverse Osmosis/Deionization Systems to Purify Tap Water for Reef Aquaria
http://reefkeeping.com/issues/2005-05/rhf/index.htm

[HighlandReefer]

Using a pH meter that runs on a battery can help to prevent electrical interference from other equipment like lights and the RK, which has been reported as a problem.

[JTL]

No doubt the more expensive ones are better, but will the cheaper single calibration ones be acceptable. I admittedly am a novice but how tight do the PH measurements need to be? I believe the Hanna Checker is a two point meter.

[HighlandReefer]

I have used the Milwaukee meter which is accurate down to 0.0. I traded it in for the Pinpoint dual calibration which is accurate down to 0.00. There is a difference if your tank runs at a pH level at the low end or high end levels. It may make you feel better if your pH is at 7.89 rather than 7.8. :lol:

I would not buy a single calibration meter, since they can be off significantly from what I have heard other hobbyists state about them when compared to the dual cal. meters. The cheaper models are usually single calibration meters the last time I checked. ;)

[Flipper62]

I like the PinPoint PH meter. For the reason that it does read right down the the 0.000.

Just like the COM-100 TDS meter. It reads right down to the 0.000. Most meters will read 0.0 untill the TDS gets to 1.0.Then it will start reading 1.1....1.4...ect.

Just pease of mind I guess

[JTL]

Assuming I purchase a two point meter, what two points should I calibrate? 7 and 4 or 7 and 10?

[Flipper62]

This is what it says in the PinPoint instructions.

• Two Point Calibration (Use only high-quality, fresh calibration fluids)
• For maximum performance the PINPOINT pH Monitor should be
calibrated immediately. Proper calibration requires the use of 2 different
fluids; one of which must be #7.00. Any combination of either (#7.00
and #4.00) or (#7.00 and #10.00) will give equally excellent results.
• All calibration fluids should be room temperature 68°- 86°F (20°- 30°C)

[HighlandReefer]

I would use the fluids in the range where testing results are expected, 7 & 10.

[JTL]

Thanks for all the info.

[Rybren]

I have the Milwaukee pH600 meter. It doesn't hold its calibration very well and needs to be recalibrated at least weekly. I certainly won't be buying another one.

[Frogmanx82]

i have to say I'm not real happy with the Milwaulkee meter either. The calibration is hyper sensitive making it very difficult to dial in. The smallest possible turn of the dial sends the meter off by a full point. I check my tank against the salt premix which is pretty consistent at 8.3 for calibration.

[JTL]

I think I will try the Hanna Checker. There is a Pinpoint on eBay for $27 + $13 shipping but it has one probe that is bad and another one that is supposedly new but leaking solution around the cap. Temping to buy this but if the probes are shot that is another $50. It is my understanding that the Pinpoint probes need to be replaced every 12-18 months. Cheaper to buy a Hanna Checker and throw it away. Maybe not as accurate but close enough.

[Rybren]

I check my tank against the salt premix which is pretty consistent at 8.3 for calibration

Interesting. I'll have to try that method myself.