Can't correct: High magnesium, low Ph

[percula99]

I have been suffering through high magnesium and low Ph for over a year now and have tried several things but can't seem to beat this.

First of all I have a heavily stocked 180. I love lots of fish and have 20 in my reef so lately my nitrates are slightly elevated. My parameters are:

- Nitrate: 20 (Red Sea)
- Phosphate: 0.08 (Red Sea)
- Calcium: 430 (Salifert)
- Magnesium: 1567 (Salifert)
- Ph: 7.61 (Pinpoint probe)
- dKh: 8.06 (Salifert)
- Sp. Gr.: 1.026 (Refractometer)
- Temp.: 78.7F (ReefKeeper Lite probe)

I have not added magnesium to my reef in over ten months but the level remains high, even after 50 gallon monthly water changes (and sometimes more) with Instant Ocean salt. New IO salt tests at 1244. (NOTE: I bought Fauna Marin calibration fluid and Salifert Magnesium test kit was reading 5% high.) I believe you should leave high magnesium alone and let time and water changes drop it but that has not been the case as I said in ten months.

Pinpoint Ph probe is new and recalibrated twice to make sure. The readings did not make sense to me so I contacted Pinpoint manufacturer. They said if I calibrated to 7 and to 10 and believe that, why don't I believe 7.61. That makes sense to me, so 7.61 it is. Salifert read 8.15. New IO reads at 7.88 (probe). I have tried leaving all the cabinet doors open to ventilate the sump area. My hood is wide open. I have added a fan over the sump and added two wooden air stones to the sump for a week and the Ph did not budge. I tried aerating water in a bucket for several hours outside and still no change. I resist using kalkwasser because I two part dose.

I do dose Red Sea NO3PO4X (35ml/day). This could be part of the problem with my Ph but I would hate to see the readings without it. I have been using it for 2 years now and for the most part nitrate readings were below 5 until the last few months.

I might have forgotten something here. If I can get a conversation going I can fill in what I might have missed.

 

[RobZilla04]

So you are getting different pH readings from different tests? I cannot speak from experience with probes, but I can suggest trying a couple of manual pH tests to get accurate readings. If those are consistent you can deduce if the probe is correct or not.

 

[nereefpat]

Your Mg is higher than natural seawater, but it shouldn't cause any problems. Some reefers keep Mg elevated.

I wouldn't worry about the pH.

Are you having some problems with livestock? If not, then I wouldn't worry about either value.

 

[Cheapreef]

When you calibrate the probe are you using the small packes or do you buy the bottles? IMO I would try some new 7 and 10 packets, float to temp match your tank. Make sure you let the probe level out really well at each point and be sure the probe is clean and no micro/air bubbles. My tank runs super low PH as well (7.68-7.9) , I just built a Co2 scrubber a week or so ago, works great but it's going to be pretty expensive to run. The weather we have up here doesn't help our cause, never a window open and air tight homes make for high Co2 especially in the basement.

 

[percula99]

As I mentioned, I have calibrated the Ph probe. You buy a solution that is at 7.0 Ph and calibrate the probe to that. Then another with a Ph of 10.0 and calibrate to that. Go back and forth a few times to make sure the readings are stable and the probe is accurate. When I contacted the probe manufacturer I spoke directly with the guy responsible for making the calibration fluids and he guaranteed me the solutions were accurate. Hobby grade test kits like Salifert are ball park at best. My Fauna Marin calibration fluid showed the Salifert magnesium test kit I have is off by 5%, the calcium is off by 14% and the dKh is off by 16%. I trust the calibrated probe more than I do the test kits.

 

[percula99]

Your Mg is higher than natural seawater, but it shouldn't cause any problems. Some reefers keep Mg elevated.

I wouldn't worry about the pH.

Are you having some problems with livestock? If not, then I wouldn't worry about either value.

The fish couldn't really care less about these readings, they are all fat, healthy and eating well. Some of my corals aren't as open as they used to be. My frogspawns recently closed up and died, blue mushrooms are dying off, same with bird's nest and one acro. My alveopora and torch still look awesome as well as green hairy mushrooms and 15 inch brain.

 

[percula99]

When you calibrate the probe are you using the small packes or do you buy the bottles? IMO I would try some new 7 and 10 packets, float to temp match your tank. Make sure you let the probe level out really well at each point and be sure the probe is clean and no micro/air bubbles. My tank runs super low PH as well (7.68-7.9) , I just built a Co2 scrubber a week or so ago, works great but it's going to be pretty expensive to run. The weather we have up here doesn't help our cause, never a window open and air tight homes make for high Co2 especially in the basement.

I have done all you recommend already. Good luck with the scrubber and I can relate to your weather issues. My tank is in the basement but like I mentioned I opened all the cabinet doors and ran a fan and air stones with no improvement.

 

[nereefpat]

That's a bummer.

Since your make-up water has lower Mg, it might be worth doing a couple big water changes. This would drop the nitrates too.

You could look into using kalk to supplement Ca and alk. It can raise pH a bit.

 

[Cheapreef]

I have done all you recommend already. Good luck with the scrubber and I can relate to your weather issues. My tank is in the basement but like I mentioned I opened all the cabinet doors and ran a fan and air stones with no improvement.

Fan and Air stones will do Zero unless your drawing air from outside. Your house air is saturated and it wont help blowing more in/on your water surface. I bet if you ran a tube outside to your air pump and or skimmer inlet it would bump your PH within 24hours.

 

[percula99]

That's a bummer.

Since your make-up water has lower Mg, it might be worth doing a couple big water changes. This would drop the nitrates too.

You could look into using kalk to supplement Ca and alk. It can raise pH a bit.

Hi Pat. I regularly do 50 gallon water changes monthly on DT. Did 125 gallons once and mag was still at 1500. I did another 100 a couple of weeks later and it still stayed at 1500. :debi: Nitrates were down to 4 but have since crept back up because of fish load.

I have a doser dosing two part and I like that. Not knowledgeable about kalk. Would adding a little in the sump raise the Ph or would parameters go all out of whack if I did?

 

[percula99]

Fan and Air stones will do Zero unless your drawing air from outside. Your house air is saturated and it wont help blowing more in/on your water surface. I bet if you ran a tube outside to your air pump and or skimmer inlet it would bump your PH within 24hours.

-23C with the wind here today. I don't think running a tube outside is an option. I have kept windows open all day in the summer and still no increase in Ph.

 

[hkgar]

Do you have a skimmer? If so, run a CO2 scrubber on the skimmer air inlet.

 

[Cheapreef]

-23C with the wind here today. I don't think running a tube outside is an option. I have kept windows open all day in the summer and still no increase in Ph.

Gees dude, your asking for help I'm giving you the best option. Plumb a line into your air intake for you house since your in the basement, that is what I am in the process of doing. I'm in Edmonton I know all to well how cold it gets here, we hit -48 last year.

 

[nereefpat]

I have a doser dosing two part and I like that. Not knowledgeable about kalk. Would adding a little in the sump raise the Ph or would parameters go all out of whack if I did?

You would have to replace some of the two part with kalk. The kalk (CaOH) adds Ca and alkalinity by consuming some of the CO2 in the tank. Some folks drip in kalk, or run it through an auto top-off. You could also dose it with your doser. Although it may not meet all your Ca and alk needs, so you may still have to add two part.

It's a good suggestion to look into the CO2 issue as well.

Good luck.

 

[percula99]

Do you have a skimmer? If so, run a CO2 scrubber on the skimmer air inlet.

I do have a nice skimmer and it works quite well. Cheapreef mentioned earlier that they are expensive to run and I am retired and on a budget so I can't afford that.

 

[percula99]

Gees dude, your asking for help I'm giving you the best option. Plumb a line into your air intake for you house since your in the basement, that is what I am in the process of doing. I'm in Edmonton I know all to well how cold it gets here, we hit -48 last year.

You are right, I did ask for help and I do appreciate the input but as I mentioned earlier: "I have kept windows open all day in the summer and still no increase in Ph." With that already being said running an airline outside won't change anything either. I have already tried getting fresh air into the room with no benefit.

 

[bertoni]

When I contacted the probe manufacturer I spoke directly with the guy responsible for making the calibration fluids and he guaranteed me the solutions were accurate.

He can't make that guarantee. All calibration solutions will degrade over time, even just with the introduction of carbon dioxide from the air, I believe. Your calibration solutions might be fine, but this is why I used one-shot calibration pouches, so that I never reused calibration solution.

Another issue with pH probes is electrical interference. I might try moving the equipment onto a separate circuit somewhere away from the tank, and measuring a sample. You mentioned running the house with the windows open during better weather. I'd definitely try aerating a cup of water outside for 3 hours or so and then checking the pH. Hopefully, it wouldn't freeze solid. If the pH doesn't rise significantly, I suspect a measurement error, either in the pH or the alkalinity.

All that said, the ambient air around the tank probably is the issue. I'd check for any signs of surface films on the water column, and make sure the skimmer is producing very fine bubble, but after that, options are limited. Some people are successful with carbon dioxide scrubbers, and for some people, I thought the media was cheap enough. You could look at some of the bulk prices of the various choices. Fresher air can help where possible, but inexpensive options ten to be limited to running a line to the skimmer. pH at 7.61 might be tolerable, though. Some other issue might be affecting the coral.

I agree that magnesium at 1500-1600 ppm is fine, and I'd just ignore that. The only practical way to lower the level is through water changes with a lower-magnesium salt mix, and I don't think it's worth the cost or effort. Lots of tanks run in that zone and do very well.

I agree that Kalk sometimes helps with low pH problems, but it can be a bit of a problem to dose unless the evaporation rate is very constant. In addition, Kalk often can't consume enough carbon dioxide to solve the problem.

 

[outssider]

I tried aerating water in a bucket for several hours outside and still no change.

This pretty much proves it's a measurement error. Tank water aerated outside should be much higher than 7.6...

 

[reefkeeper78]

Try taking a sample of your tank water to a friend or lfs. Compare their results to yours. It could be your test kits have expired or a bad batch of reagent that are giving a false reading. There are also companies that you can send a water sample to for analisis.

 

[percula99]

I had already bought new test kits. I think I have it now. I reduced my calcium (doser) and my magnesium has fallen to 1425 as of last week. I reduced my NoPoX and my Ph started rising. I always suspected the NoPoX in the Ph issue.