Which one would you trust?

[allgoodsystems]

I have an aquacontroller and a pinpoint PH monitor. I am using a pinpoint PH probe.

I have a seachem and an API PH test kit.

My PH is reading 7.83 with the aquacontroller and the pinpoint monitor.
My PH is reading 8.3 with the seachem and api test kit.

I have calibrated the probe and purchased a new probe last week. I have used mutiple 7.0 and 10 pinpoint calibration fluids.

Any opinions?

 

[NicoleC]

pH monitors can go bad, but hobby test kits are notoriously unreliable.

 

[ocd_mariner]

With a new probe and calibration fluid, I'd be inclined to trust them. Especially if the ph tests are the retardedly ambiguous guess-which-color tests.

 

[mixer911]

I vote for the monitors. Agreed with chemical tests being wacky. If calabrated correctly and 2 probes are showing close, then I would go with them.

 

[allgoodsystems]

Ok. I am going to slowly raise it until the ph reads 8.3 on my monitor. If the api test kit is right then my ph will be at 8.8. If everything dies then I guess I will know the test kits were right and my pinpoint is wrong.

 

[mixer911]

Why not use the test kit and test the 7.0 or 10.0 solution and see what it reads

 

[allgoodsystems]

Why not use the test kit and test the 7.0 or 10.0 solution and see what it reads

I thought about that but the test only reads up to 8.8 and down to 7.3.

 

[mixer911]

I thought about that but the test only reads up to 8.8 and down to 7.3.

dang

 

[andywe]

The probe calbration solution would not necessarily read 7 or 10 for ph on a chemcical test kit. A probe uses electircal measurement and as such the calibration soltuion is amde for that.

The caliber of probe is as reliable as a fresh chemical test kit. Here is a test to do to rule out your probe giving a bad reading. I ahve 8 ph prbes from 3 manufacturers and can tell you probes are wrong as often as the test kits imo. I even have a PH pen which seems to keep calbration best (go figure) that I use to double check every few weeks.

Here's a suggestion:

Take a cup of tank water and put the prob in that, out of the tank and out of the sump. See if it reads the same or not. If the reading is different, then you more than likely have electrical leakage in your tank from some device. Even with a grounding rod, you are prone to have leakage effect things like probes. The current is still travelling through the water.

 

[gannmann9876]

i was wondering how to clean the coraline alge off my ph probe? also if you clean it does it need to be recalibrated?

 

[NicoleC]

7.8 ain't horrible so don't so anything drastic. Suddenly raising it to 8.2.... that's drastic. It'll also be a horrible shock to the inhabitants that have gotten used to 7.8.

What time of the day did you get this reading? Do you have algae problems?

 

[mixer911]

The probe calbration solution would not necessarily read 7 or 10 for ph on a chemcical test kit. A probe uses electircal measurement and as such the calibration soltuion is amde for that.

Not saying your wrong Andy, but isn't that what PH is, concentration of hydrogen ions in a solution. If a solution is 7 ph then chemical or electrical should still reed 7. The probe is no different than a chemical test kit. as they are both reacting to the ions. The chemical test kit might have some difference + or - though. I am no chemist by any means so I may be totally wrong. Just wondering for my own info.

 

[mixer911]

7.8 ain't horrible so don't so anything drastic. Suddenly raising it to 8.2.... that's drastic. It'll also be a horrible shock to the inhabitants that have gotten used to 7.8.

What time of the day did you get this reading? Do you have algae problems?

I agree! Another thing is to see why the reading is so low and attack that problem instead of trying to chemically alter the PH. Like Nichole said, is there algae, to much C02 in the room. Tank sealed to tight, time of test?

 

[allgoodsystems]

I agree! Another thing is to see why the reading is so low and attack that problem instead of trying to chemically alter the PH. Like Nichole said, is there algae, to much C02 in the room. Tank sealed to tight, time of test?

Time of test around 3PM. Yes. Major green algae problem but the algae didn't start until I switched to halides. It's reading 7.94 right now on the pinpoint. The seachem test is reading 8.4. I did take some sample water and test out of the tank. Same readings.

 

[DMBillies]

Time of test around 3PM. Yes. Major green algae problem but the algae didn't start until I switched to halides. It's reading 7.94 right now on the pinpoint. The seachem test is reading 8.4. I did take some sample water and test out of the tank. Same readings.

Around 3pm your pH should probably getting at or near about as high as it is getting, which means your overnight pH could be A LOT lower. Low pH, in combination with brighter lighting, can easily drive algae problems which will only serve to make your pH swing bigger.

It sounds awful weird to me that two test kits would be reading normal and your probe would be that far off though. Anyone have a portable meter they can get another reading on this thing with?

 

[allgoodsystems]

Anyone have a portable meter they can get another reading on this thing with?

That would be cool.

 

[sandalscout]

I've got a pen meter I can bring with me tomorrow to the meeting, are you close to the meeting place, or maybe you could even bring some samples to test?

I've not calibrated it for a while, but it seems to be fairly accurate in my experience.

 

[allgoodsystems]

I've got a pen meter I can bring with me tomorrow to the meeting, are you close to the meeting place, or maybe you could even bring some samples to test?

I've not calibrated it for a while, but it seems to be fairly accurate in my experience.

That would be great. I am about 3 miles from the meeting.

 

[andywe]

Not saying your wrong Andy, but isn't that what PH is, concentration of hydrogen ions in a solution. If a solution is 7 ph then chemical or electrical should still reed 7. The probe is no different than a chemical test kit. as they are both reacting to the ions. The chemical test kit might have some difference + or - though. I am no chemist by any means so I may be totally wrong. Just wondering for my own info.

I thought the same thing Rick, but I found out that the carrier can effect the reading. A chemical test measures a different value. The chemical test is designed with additives to measure the ph in saltwater, not bromide or another chemical which has drastically different properties. the ph reading may have the same results as electrical conductivity, but have a different ionic makeup So I do not trust a probe calbration fluid on a chemical reaction test. It's just a potential factor.

If you tested salinity probe calbration fluid on a refractometer, it would be different than the probe's reading at the targeted result.

 

[allgoodsystems]

Well....SandalScout loaned me a portable PH tester. Nice little tester by the way. It got almost the exact same reading as the pinpoint monitor and aquacontroller. So I am going with the lower reading the probes got. Makes you wonder about the color code tests. Two seperate kits, different brand, .5 off.