Low pH headaches

[FrostyChicken]

I just got my Apex controller about 2 weeks ago and I love it. One of the things I love is the ability to see how the tank is doing both right now and over a period of time. Now that I can keep a better eye on things I'm noticing that my pH is alarmingly low. Right now it's sitting at 7.6 and slowly creeps down throughout the day. I tested for Alk last night and if my test was to be believed it was over 12 dKH (that's as high as the test would report). I tried opening the window right next to the tank for several hours but this didn't seem to have much effect either. Any help anyone could offer would be greatly appreciated. My monti is starting to show white patches after growing so well for a long period of time. Other than the Apex the only significant change I've made is to add a 2 Little Fishies GFO reactor about 3 weeks ago running Premium Aquatics GFO. I'm not sure if this is significant or not. I also use a 1 gallon milk jug with an IV drip rate valve to drip lime water in over a several hour period. I'm open to any suggestions anyone has.

 

[downbeach]

Are you sure your probe is properly calibrated? Have you been adding any pH buffers? If so, that might be why your Alk is so high. Are you dosing anything?

 

[FrostyChicken]

As a follow up I've noticed that if I use lime water exclusively for a small top off (my system is 160 gallons total water volume) then the pH will climb for a bit then start dropping right back off. I burn off about 1.5 gallons of water a day. Is using lime water for all of my topoff needs OK?

 

[FrostyChicken]

I used the calibration liquid that came with the Apex before I put it in the tank about 2 weeks ago so I think that it's reading properly.

 

[disc1]

As a follow up I've noticed that if I use lime water exclusively for a small top off (my system is 160 gallons total water volume) then the pH will climb for a bit then start dropping right back off. I burn off about 1.5 gallons of water a day. Is using lime water for all of my topoff needs OK?

If you get the alk back down then using limewater for all your topoff should work fine.

I'd have to doubt those pH readings. At 7.6 the calcium carbonate in the rocks and sand would start to dissolve and that would have the natural effect of raising the pH back up. Anytime you see pH readings that low you have to question the measurement.

 

[FrostyChicken]

Well that's frustrating. I know that after going through the pH probe calibration instructions it recommended using the solutions to see if they read what the package had them labeled at and in both cases (7.0 and 10.0) they did. I've seen some postings online mention Magnesium. I have never tested for that before but could that play into what I'm seeing?

 

[tmz]

What is the water volume of the aqaurium?

Monitors and probes,sometimes give inaccurate results due to electrical interference articularly from light ballasts ,ime.

 

[baldbean]

When you calibrated the probe did you get the solutions to your tanks temp? Just thought I would toss that out there.

Also you may want to get a pH test kit for sanity. I use a probe on my Apex too, but when things don't look I go to the test kit.

 

[FrostyChicken]

TMZ - It's 160 gallons total volume. I just switched over to LEDs last night so I don't think ballasts are an issue since the problem didn't fix itself.

bald - Yes, I saw in the Apex Comprehensive manual that equalizing the temps was a good idea so I floated the packets in the sump for about 15 minutes.

 

[FrostyChicken]

When I got home today I tested the water with 2 different pH tests and both of them matched up with my Apex. I did add some Magnesium and I noticed that my pH did shoot up for a minute (I purposefully added it right over the pH probe) but I don't know if this is an indicator of a magnesium deficiency or just another buffer of some sort that's in the solution.

 

[tmz]

Magnesium enables more calcium and carbonate to remain in solution.. It replaces calcium on some forming calcium carbonate cystals stopping their growth. Thus , it slows a biotic precipitation alalowing higher levels of carbonat alkainity and calcium to remain in solution. The recoommended level for magnesium is 1280ppm to 1350 ppm or a little higher.

I'd guess dosing it by the probe might have caused a momentary upswing, from magnesium hydroxide perhaps , but it is not a buffer.

 

[bertoni]

I agree that the magnesium won't affect the tank's pH directly in any measurable way. I also doubt that the pH actually is below 7.6. I might try aerating a cup of water outside for three hours and checking its pH. Also, sometimes surface films can reduce aeration and cause low pH problems, although that's rare. It's easy to check, though.