High Nitrate/Bacteria Bloom = Low PH?

[JPK_Esquire]

I’ve got a new 180g tank (7 weeks) that is consistently running low ph (7.7 - 7.8). I added a CO2 scrubber which helped a bit, but still running pretty low. Opening a window helps some, but not a ton.

I’m feeding the tank a ton (definitely overfeeding) in order to get a Regal Angel to eat that’s been in there a little over two weeks. It looks like I may have a little bacteria bloom, but not terrible. I run a UV intermittently, to address the bloom.

Tank currently has 2x clowns, Regal Angel, Coral Beauty, Flame Angel, Lawnmower Blenny.

Salinity: 1.025
PH: 7.7
ORP: 370
Alk: 6.9 (3 nights ago)
NO3: 32-50 ppm (last night)

I plan to do a full chem test tomorrow (KH, Ca, Mg, PO4, NO3). Will report back.

Would overfeeding, high nitrates, or potential bloom send PH low? Also, PH has been low (below 7.85) since setting up the tank.

 

[homer1475]

Bacterial bloom will rob O2 causing Co2 to rise, which in turn causes PH to be lower.

 

[SPR1968]

I wouldn’t worry to much your fine at that level of pH and remember there could also be an element of test error/probe inaccuracy as well

On my S650 the apex pH probe says it sometimes drops to around 7.7 overnight, but I don’t worry anymore. When I randomly test with an ELOS kits it’s always fine.

Your alkalinity is on the low side of ok as well so I would maybe raise that a little, as not much ‘wiggle room’ for it to drop.

If you have a UV I would just run it 24/7 that’s what I do anyway on both my tanks.

 

[JPK_Esquire]

Measurements tonight were the following:

Alk: 6.7 (Hanna)
Ca: 400 (Red Sea)
Mg: 1280 (Red Sea)
PO4: .16 (Hanna)

Dosed: 114 ml Red Sea Found C, 50 ml Red Sea Found B

Also, I am wondering if the PH probe may be need to be calibrated (odd considering how the tank is only 7 weeks old). I tested with Red Sea Kit and it reads 8.2. I've got a calibration kit coming Friday.

 

[JPK_Esquire]

I wouldn’t worry to much your fine at that level of pH and remember there could also be an element of test error/probe inaccuracy as well

On my S650 the apex pH probe says it sometimes drops to around 7.7 overnight, but I don’t worry anymore. When I randomly test with an ELOS kits it’s always fine.

Your alkalinity is on the low side of ok as well so I would maybe raise that a little, as not much ‘wiggle room’ for it to drop.

If you have a UV I would just run it 24/7 that’s what I do anyway on both my tanks.

I would totally run theUV 24/7 if I could. However, I’ve got an overheat problem caused by the Sicce Pump I am using in the sump to feed the UV (see link below to a different thread where I discussed and troubleshot the problem). Right now, I am running it every other hour, which seems to keep the temp fairly stable. Not a long term solution, as I am not wild about the Energy Bar coming on and off 12x a day.

Pentair UV Killing Flow

For those of you following along at home, I finally got around to bucket testing various scenarios, and think I have arrived at a conclusion for the pressure loss. If you didn't read the original post, I am using a Sicce Syncra Silent 5.0, which allegedly provides 1321 gph. I am running 24" of...

www.reef2reef.com

 

[Randy Holmes-Farley]

Also, I am wondering if the PH probe may be need to be calibrated (odd considering how the tank is only 7 weeks old). I tested with Red Sea Kit and it reads 8.2. I've got a calibration kit coming Friday.

Did you calibrate it when you got it? They do not come appropriately calibrated.

7 weeks is not unusual to need recalibration. Analytical labs may recalibrate multiple times a day.

 

[ScottB]

Hobby grade pH probes are notoriously error prone. They seem to cause more (over reaction) problems than they solve. I once tested someone's water that was chasing pH using buffer and she had dkH >18.

It is extremely rare for a stable tank to have pH levels that are a problem.

Cloudy water is a problem. Make sure you are agitating the water to better oxygenate it. Skimmer running well, powerheads rippling the water surface, run a bubbler if you have one.

 

[JPK_Esquire]

Did you calibrate it when you got it? They do not come appropriately calibrated.

7 weeks is not unusual to need recalibration. Analytical labs may recalibrate multiple times a day.

Thanks Randy. I DID calibrate it when I got it, but I am thinking it may slipped. No corals in the tank yet, so I am not terribly concerned about it.

 

[JPK_Esquire]

Hobby grade pH probes are notoriously error prone. They seem to cause more (over reaction) problems than they solve. I once tested someone's water that was chasing pH using buffer and she had dkH >18.

It is extremely rare for a stable tank to have pH levels that are a problem.

Cloudy water is a problem. Make sure you are agitating the water to better oxygenate it. Skimmer running well, powerheads rippling the water surface, run a bubbler if you have one.

Thanks. The problem may be I am not agitating the water enough. In order to give the Regal Angel EVERY opportunity to eat and pickup the food thats fallen to the bottom, I am leaving the powerheads and return off for 30 minutes, and then kick the return pumps back on for probably another 30+ minutes, before I restart the powerheads, which promptly picks up all the massive amounts of uneaten food.

At this juncture, I am somewhat to the point where I don't want to sacrifice the long-term viability of the tank for one fish (although I REALLY REALLY like this fish, and if he doesn't go in now, I'm likely not having one in this tank). Started cutting the food back to a more realistic level yesterday and keeping the return pumps off for only about 15-20 minutes. Also added a small (relative) cleanup crew today to start taking care of the uneaten food.

 

[Randy Holmes-Farley]

Hobby grade pH probes are notoriously error prone. They seem to cause more (over reaction) problems than they solve. I once tested someone's water that was chasing pH using buffer and she had dkH >18.

It is extremely rare for a stable tank to have pH levels that are a problem.

Cloudy water is a problem. Make sure you are agitating the water to better oxygenate it. Skimmer running well, powerheads rippling the water surface, run a bubbler if you have one.

I'm not aware that a properly calibrated hobby pH probe is error prone. Calibration can certainly be done incorrectly, and a meter that allows only 1 point calibration is not desirable.

 

[ScottB]

I'm not aware that a properly calibrated hobby pH probe is error prone. Calibration can certainly be done incorrectly, and a meter that allows only 1 point calibration is not desirable.

Perhaps just my experience. The idea of buying calibration fluid in bulk bores me. For my APEX probe, do I need to by APEX solutions or are there generics? Same complaint with the conductivity probe. They both tend to trend low over time.

 

[Randy Holmes-Farley]

Perhaps just my experience. The idea of buying calibration fluid in bulk bores me. For my APEX probe, do I need to by APEX solutions or are there generics? Same complaint with the conductivity probe. They both tend to trend low over time.

Any quality pH calibration fluid works with any meter, as long as the meter allows you to enter the pH value of the fluids you are using.

 

[JPK_Esquire]

Mystery solved! Calibration fluids received today (link below to the ones I purchased off Amazon). Before calibrating, PH probe attached to Apex showed 7.74, but when checked against the 7.0 fluid Apex probe showed 6.62, so a whole .38 off (thats quite a bit IMO). The differential is consistent with the test Monday night where probe was showing 7.83 and Red Sea test was showing 8.2.

I calibrated the probes using the 7.0 and 10.0 solutions and PH via the probe now shows 7.92, which isn't quite a .38 increase, and I suspect is still a little on the low side. However, I am much more comfortable with 7.92, especially since I am not running any lights right now. I'll check against the Red Sea kit again tonight. Just goes to show, before questioning that something may be wrong with your PH, check the reliability of the data (I.e., check the probes).