Bizarre Water Parameters

[aandrin00]

Hi everybody! I've gotten so much help reading posts here on R2R in the past, so I'd like to thank the community for that, but this is my first time actually posting. I'm super confused, so I'm hoping you guys might be able to shed some light.

First some background: I set up this 20 gallon all in one tank about 3 months ago with dry rock. Since it's bare bottom and has a relatively small volume of rock I also added about a dozen of those 2" marine pure cubes and a bunch of the marine pure gems. I used Brightwell microbacter start and dosed the recommended amount of ammonia. Up until about 10 days ago the tank had no livestock, at which point I added a midas blenny. I turned the lights on about 5 days ago when I added a few frags.

A couple of days after adding the fish I tested ammonia and nitrite just to be safe and both were at 0 ppm. Yesterday I tested all of the following parameters and almost none of the results make sense to me.

pH = 7.64 (I just calibrated my pH probe, turns out it was way off - it was reading close to 8 until I calibrated). The red sea test kit shows about 8.0 though.
S.G. = 1.025
Ammonia = 0.2 ppm (red sea)
Nitrite = 0 ppm (red sea)
Nitrate = 0.00 ppm (hanna)
Phosphate = 0.03 ppm (hanna)
Alkalinity = 6.7 dKH (hanna)
Calcium = 393 ppm (hanna)
Magnesium = 1540 ppm (red sea)

I've been using HW reefer salt, and since the tank was set up I've done several large water changes. Yesterday after I measured all these parameters I did another 5 gal water change. I've been mixing up salt water and it stays circulating and heated in a 20 gal container until I need it. After yesterday's water change I mixed up a new batch to have on hand - stuck the pH probe in there out of curiosity and it was at 8.15, this morning it was down to 8.00, and now it's 7.92.

- The pH of 7.64 in the tank seems crazy low. It's 7.77 now but still low.
- The 0.2 ppm ammonia I guess I understand because of the new fish addition, but there's so much bio media in the tank and I dosed bacteria weekly (microbacter start then microbacter clean) for the first several weeks.
- Nitrate at 0.00 ppm makes no sense to me. Got the same reading about a week ago too.
- Alkalinity is incredibly low, I don't understand since there should be nothing using it. The few frags I added 5 days ago are thumbnail sized.
- Calcium and Magnesium are also both out of whack.

Another thing to note is that from approx week 2 until around the time I added the fish I kept getting pretty cloudy water. I attribute that to bacterial blooms, that's the reason I quit adding the brightwell bacteria additives.

Is there any easy way to explain these bizarre water parameters? Almost none of them make sense to me! Thank you for taking the time to read this, and any input would be greatly appreciated!!

 

[arking_mark]

hw-Marinemix Reefer purportedly mixes to Calcium at 445-450 ppm, Alk of 9.0 dKH, Magnesium at 1380 ppm.

If your #s are low, it's possible your salinity measurement is off. There are many threads on salinity measurement issues. At this point in my reefing hobby, I only trust my Tropic Marin High-precision Hydrometer. It's also possible your other measurements are off with our hobby grade test kits.

Looking at your tank, I'm betting your low pH is due to poor aeration. These AIO tanks typically do not provide enough flow/aeration with the return pump. Without proper flow/aeration your tank's CO2 builds up which lowers pH. There are other reasons for low pH and you can do a cup aeration test to help identify your pH issue.

The ammonia reading is probably a testing error. Red Sea test kits are notorious for this.

I can believe you have no nitrates with a new tank and the bacteria you've been adding.

So my bet is:
1. Your salinity measurement is off
2. Your tank has poor aeration
3. Everything else is normal

 

[Randy Holmes-Farley]

FWIW, alk of 6.7 dKH is not "incredibly low' It is still higher than the ocean and not a big concern unless it drops significantly lower. But boosting it to 8 dKH is a fine plan.

Agree to look into salinity measurement issues.

I wouldn't worry too much about pH right now, and it may not be accurate.

What ammonia test? Some read 0.2 ppm at the drop of a hat. API, for example.

 

[aandrin00]

Thank you both for your comments and suggestions!

I measured specific gravity with one of the BRS refractometers, and checked with the calibration solution right before. I can't imagine that the solution being at room temp vs the tank water being at 78 F makes a significant difference, would it? If salinity is off, would it be safe to assume Alk, Cal, and Mag would be proportionally higher/lower? Mine don't seem to be in the right proportions.

The ammonia test was done with a Red Sea test kit. I don't necessarily trust this kit so much since I was still picking up ammonia weeks after my cycle should have theoretically been complete.

Encouraged to hear that nitrates being at 0 ppm isn't strange, guess all those bacteria are doing their job too well and it'll eventually catch up to them. For now hopefully this keeps and nuisance algae at bay.

I will definitely try a cup aeration test with both tank water and the new salt water I have stored. I will also double check the calibration of the pH probe. I was really excited to start using this probe on this new tank, but now I have more questions and doubts than anything.

I'll try to repeat all the tests tonight on the tank water as well as the stored new salt water.

 

[aandrin00]

It took me a couple of hours, but last night I ran a whole bunch of tests on the tank water as well as the new salt water being stored. I did an aeration test on both the tank and new salt water (air stone in a cup of the water for 30 minutes) and I think the results of that point to high CO2 levels in here. Also, I checked the calibration of the pH meter and refractometer again, both were fine. See below for the results, (RS stands for Red Sea test kit and H for Hanna checker):

Tank Water:
pH (in tank): 7.76
pH (after aeration): 7.76
Specific Gravity: 1.025
Ammonia (RS): 0.2 ppm
Nitrite (RS): 0 ppm
Nitrate (H): 0.00 ppm
Phosphate (H): 0.06 ppm
Alkalinity (H): 6.8 dKH
Calcium (H): 417 ppm
Magnesium (RS): ~1420-1460 ppm (hard to tell exactly when the titration is complete)

New Saltwater:
pH (in storage container): 7.86
pH (after aeration): 7.78
Specific Gravity: 1.025
Ammonia (RS): 0 ppm
Nitrite (RS): 0 ppm
Nitrate (H): 0.08 ppm
Phosphate (H): 0.01 ppm
Alkalinity (H): 7.3 dKH
Calcium (H): 413 ppm
Magnesium (RS): ~1380-1440 ppm

My conclusions/questions:
- CO2 likely very high in here since aerating the new salt water brought down the pH to the level measured in the tank. My apartment is fairly new construction so likely insulated well and I am dosing CO2 in a planted tank in the next room over - would be interesting to get a CO2 meter and see what the actual concentration is.
- I don't like seeing the ammonia reading in the tank, even though I know the red sea test kits will do that. For now I'll keep up with water changes.
- I see how some of these test kits could give erroneous results, especially the red sea magnesium test, where measuring out precise amounts of sample/reagent is critical.
- I know alkalinity is a relatively complex parameter with multiple factors influencing it. Would elevated CO2 suppress the alkalinity level as well as pH, or does alkalinity stay constant regardless of the CO2 level and only pH changes? In other words, could elevated CO2 be the reason I'm measuring low pH AND alkalinity?

Thank you all, I know these posts are pretty long, so I really appreciate all of you who read it and responded. This has been a good exercise in getting in tune with my tank.

 

[arking_mark]

The addition or subtraction of CO2 does not impact Alkalinity.

Based on your #s;

This puts you CO2 levels at around 1300ppm.

Assuming your measurements are good, you may want to look at getting your in home CO2 levels down a little.

 

[Jcar]

Dose prime to counter the ammonia. Probably should not add anything else until the cycle is fully complete and you have no nitrite and nitrate reading. Add some live rock that has been in a tank for 3 or more months it will probably help speed things up. I'm thinking of getting a midas blenny myself they look like they have cool personalities.

 

[Randy Holmes-Farley]

FWIW, I would not be sure the 0.2 ppm is not just a false ammonia reading.

 

[Dan_P]

It took me a couple of hours, but last night I ran a whole bunch of tests on the tank water as well as the new salt water being stored. I did an aeration test on both the tank and new salt water (air stone in a cup of the water for 30 minutes) and I think the results of that point to high CO2 levels in here. Also, I checked the calibration of the pH meter and refractometer again, both were fine. See below for the results, (RS stands for Red Sea test kit and H for Hanna checker):

Tank Water:
pH (in tank): 7.76
pH (after aeration): 7.76
Specific Gravity: 1.025
Ammonia (RS): 0.2 ppm
Nitrite (RS): 0 ppm
Nitrate (H): 0.00 ppm
Phosphate (H): 0.06 ppm
Alkalinity (H): 6.8 dKH
Calcium (H): 417 ppm
Magnesium (RS): ~1420-1460 ppm (hard to tell exactly when the titration is complete)

New Saltwater:
pH (in storage container): 7.86
pH (after aeration): 7.78
Specific Gravity: 1.025
Ammonia (RS): 0 ppm
Nitrite (RS): 0 ppm
Nitrate (H): 0.08 ppm
Phosphate (H): 0.01 ppm
Alkalinity (H): 7.3 dKH
Calcium (H): 413 ppm
Magnesium (RS): ~1380-1440 ppm

My conclusions/questions:
- CO2 likely very high in here since aerating the new salt water brought down the pH to the level measured in the tank. My apartment is fairly new construction so likely insulated well and I am dosing CO2 in a planted tank in the next room over - would be interesting to get a CO2 meter and see what the actual concentration is.
- I don't like seeing the ammonia reading in the tank, even though I know the red sea test kits will do that. For now I'll keep up with water changes.
- I see how some of these test kits could give erroneous results, especially the red sea magnesium test, where measuring out precise amounts of sample/reagent is critical.
- I know alkalinity is a relatively complex parameter with multiple factors influencing it. Would elevated CO2 suppress the alkalinity level as well as pH, or does alkalinity stay constant regardless of the CO2 level and only pH changes? In other words, could elevated CO2 be the reason I'm measuring low pH AND alkalinity?

Thank you all, I know these posts are pretty long, so I really appreciate all of you who read it and responded. This has been a good exercise in getting in tune with my tank.

The fact that you can get a zero ammonia reading with your ammonia test kit means there is something in the aquarium water causing the test result to be >0 ppm, though it does not have to be ammonia. Amino acids can give false positives.

With the system’s relatively low pH, 0.2 ppm total ammonia does not represent a toxic level free ammonia.

I guess my advice is don’t panic about the ammonia reading and remain vigilant.