astreck827
Active Member
I apologize in advance for the long read but I want to include as much detail as possible. TLDR at end.
Hoping for some help here because if the readings that I'm getting are correct, I have some serious issues that require swift correction. I have been measuring pH using a salifert kit up until now and typically get between 8.15-8.3. I had an old pinpoint pH meter with no probe that I got in a bulk buy from a system shut down that I hadn't used until today, and I am somewhat concerned with the readings I'm getting. I decided to order a new probe after doing some research and seeing a post by Randy saying that the pH test kits are not very accurate and a probe is the way to go. So I ordered a probe from Amazon and received it today. This was not an expensive probe, only $20, and it is not the same manufacturer of the meter, but I had assumed that since they are able to be calibrated and the connection is a standard "BNC" type it would be OK. For calibration, I used Hanna calibration fluid with pH of 7.01 and 4.01 - another caveat here, they were expired by about 3 years, but I didn't think that would affect anything since they are individually sealed fluid pouches with no damage, and the 7.01 pouches were still in a box covered in cellophane. Once calibrated to 4.01 and 7.01 (several times at each pH), I submerged the probe in my sump and the numbers I got were NOT what I expected. The meter was quickly fluctuating between about 7.1 and 7.55 and everywhere in between, I would say average ~7.4. I gave it a few minutes and appreciated no change in the range or the speed of fluctuations. I then moved the probe to my frag tank, where it read much more stable at about 7.8 (7.77-7.82). I tried my main display and display fuge and got similar results to the frag tank. My first thought was to double check my alk - I had recently experienced a large uptake in alk from my system and attributed it to a coral growth spurt. I changed my GFO about 2 days ago and my phosphates dropped from about 0.2 to 0.06, and thought I was seeing a good effect from the change. It has happened before in the past where I hit a sweet spot and suddenly my alk consumption jumps. Yesterday I actually increased my 2 part dosing from 75 mL/day to 120 mL/day and my alk this am was 8.7 dKH. Retest from sump showed 8.6 on the Hanna checker and 8.5 from the frag tank. I ran a salifert test and got 8.0. I also checked the pH with salifert from both tanks and could not see a discernible difference in color between the 2 tanks. I rechecked the calibration fluids and they were still spot on. I then mixed some of the 4.01 buffer solution powder that the probe came with and it was right on the dot.
Is this possible that there is so much of a difference between sump and connected tanks? The readings from the sump were literally right next to my skimmer which I thought would increase the pH. Am I overlooking something simple? What could be interfereing with my readings? I was really hoping to see a nice 8.3-8.4 given the increase in alk dosing. I also run kalk on a doser and I dose 50 mL/hr around the clock for my 220 total gallon system. I recently changed from Fritz to Red Sea blue bucket. My sump is full of live rock and I run a chaeto reactor, GFO reactor, and biopellet reactor. I dose BRS 2 part + mag and kalk, and supplement with Seachem Fuel. Everything in my tank looks good. SPS are growing, acros are fuzzy, torches and hammers are fat, and gorgonians (which usually tell me if something is off) were fuzzy as ever.
TLDR; I used a pH probe from the first time and my sump pH was ~7.4 while my DT and frag tanks were ~7.8.
Hoping for some help here because if the readings that I'm getting are correct, I have some serious issues that require swift correction. I have been measuring pH using a salifert kit up until now and typically get between 8.15-8.3. I had an old pinpoint pH meter with no probe that I got in a bulk buy from a system shut down that I hadn't used until today, and I am somewhat concerned with the readings I'm getting. I decided to order a new probe after doing some research and seeing a post by Randy saying that the pH test kits are not very accurate and a probe is the way to go. So I ordered a probe from Amazon and received it today. This was not an expensive probe, only $20, and it is not the same manufacturer of the meter, but I had assumed that since they are able to be calibrated and the connection is a standard "BNC" type it would be OK. For calibration, I used Hanna calibration fluid with pH of 7.01 and 4.01 - another caveat here, they were expired by about 3 years, but I didn't think that would affect anything since they are individually sealed fluid pouches with no damage, and the 7.01 pouches were still in a box covered in cellophane. Once calibrated to 4.01 and 7.01 (several times at each pH), I submerged the probe in my sump and the numbers I got were NOT what I expected. The meter was quickly fluctuating between about 7.1 and 7.55 and everywhere in between, I would say average ~7.4. I gave it a few minutes and appreciated no change in the range or the speed of fluctuations. I then moved the probe to my frag tank, where it read much more stable at about 7.8 (7.77-7.82). I tried my main display and display fuge and got similar results to the frag tank. My first thought was to double check my alk - I had recently experienced a large uptake in alk from my system and attributed it to a coral growth spurt. I changed my GFO about 2 days ago and my phosphates dropped from about 0.2 to 0.06, and thought I was seeing a good effect from the change. It has happened before in the past where I hit a sweet spot and suddenly my alk consumption jumps. Yesterday I actually increased my 2 part dosing from 75 mL/day to 120 mL/day and my alk this am was 8.7 dKH. Retest from sump showed 8.6 on the Hanna checker and 8.5 from the frag tank. I ran a salifert test and got 8.0. I also checked the pH with salifert from both tanks and could not see a discernible difference in color between the 2 tanks. I rechecked the calibration fluids and they were still spot on. I then mixed some of the 4.01 buffer solution powder that the probe came with and it was right on the dot.
Is this possible that there is so much of a difference between sump and connected tanks? The readings from the sump were literally right next to my skimmer which I thought would increase the pH. Am I overlooking something simple? What could be interfereing with my readings? I was really hoping to see a nice 8.3-8.4 given the increase in alk dosing. I also run kalk on a doser and I dose 50 mL/hr around the clock for my 220 total gallon system. I recently changed from Fritz to Red Sea blue bucket. My sump is full of live rock and I run a chaeto reactor, GFO reactor, and biopellet reactor. I dose BRS 2 part + mag and kalk, and supplement with Seachem Fuel. Everything in my tank looks good. SPS are growing, acros are fuzzy, torches and hammers are fat, and gorgonians (which usually tell me if something is off) were fuzzy as ever.
TLDR; I used a pH probe from the first time and my sump pH was ~7.4 while my DT and frag tanks were ~7.8.
