I’m Stumped

[Bastray]

I have been having some weird chemistry issues in my tank the last couple of months after I dosed Chemiclean to rid a long lasting Cyano problem that I couldn't beat.

After I dosed Chemiclean the Cyano was was gone and has remained gone. I followed the directions to the T. My phosphates and nitrates have been great since as well. Here are my parameters.

Alk- 8
Calcium- 420
Mag - 1450
Po4- .03-.06
Nitrates - 5-10
Ph - 7.6-7.8 or 8.1-8.2 (this is the weird one)

So since during Chemiclean my Monti's have not been good since. All other SPS looks good. My pH will fluctuate as low as 7.6 and I've seen it go up as high as 8.3. It will be higher a few days post weekly water change and then will drop over the week. My Alk consumption will follow that trend. My trident will dose up to 90ml a day but then today it is dosing 60ml because the pH has dropped. It's Tuesday and I do water changes on Thursday. I do 20% weekly water changes.

Prior to this my tanks natural pH was between 8.1-8.2. What could be causing all this instability? I keep hoping I can ride this out and the tank with stabilize itself, but it's been 2 months of this and not getting better. I have a co2 reactor I have hooked up and that doesn't seem to help much. I feel that I am doing everything I should be doing and this weirdness won't go away. My system is fairly simple just using skimmer, carbon, tons of flow, good lights, and water changes for nutrient export.

Anyone run into something like this?

 

[Dragon52]

Since I attached the extra hose that came with my skimmer from the top of the air inlet to the outside of the sump my PH has stayed in the 8-8.3 range. I don't have a scrubber on my system.

 

[Bastray]

I don't think it is related to the air in my house or the normal stuff that lowers pH. My pH used to rarely drop below 8. Now it goes down to 7.6 often. The tank is just not right and something is off. Just can't figure out what is off.

 

[dwest]

I don't think it is related to the air in my house or the normal stuff that lowers pH. My pH used to rarely drop below 8. Now it goes down to 7.6 often. The tank is just not right and something is off. Just can't figure out what is off.

Are there more people in the house on the low pH days?

 

[Dkeller_nc]

A few comments -

Your trident, if operating correctly, will not change its dosing based on the tank's pH. The trident, and other similar auto-titrators, uses an automated version of the typical laboratory alkalinity titration. And while that method uses a pH probe to correctly determine the end point of the titration, there's going to be very little difference between the total amount of acid added (which is an estimate of the alkalinity) when the pH starts at 8.3 and when it starts at 7.6.

You mention that you have a "CO2 reactor" - I'm going to assume that means a CO2 removal reactor. If that's correct, is the adsorption media one of the indicating types (i.e., turns blue when exhausted)? If it isn't, then it may well be that you've simply exhausted the media. Testing to see whether your tank's pH is a result of absorbed CO2 is relatively simple if you have a calibrated pH meter/pen. Pull a cupful sample out of your tank, and measure the pH. Then place the sample outside, and bubble air through it for 10 minutes with an air pump. Then re-check the pH. If the difference between these two measurements is over 0.2 pH units, then either the inside of your home has a good deal more CO2 in the air than the outdoor air, or your tank is not in equilibrium with the indoor air from insufficient gas exchange, or both.

Another explanation for the week-long pH drop that you've observed is that your system has generating a good deal of organic acids into the tank water (from decay), and your water change is diluting some of this, which results in a pH rise.

 

[Bastray]

A few comments -

Your trident, if operating correctly, will not change its dosing based on the tank's pH. The trident, and other similar auto-titrators, uses an automated version of the typical laboratory alkalinity titration. And while that method uses a pH probe to correctly determine the end point of the titration, there's going to be very little difference between the total amount of acid added (which is an estimate of the alkalinity) when the pH starts at 8.3 and when it starts at 7.6.

You mention that you have a "CO2 reactor" - I'm going to assume that means a CO2 removal reactor. If that's correct, is the adsorption media one of the indicating types (i.e., turns blue when exhausted)? If it isn't, then it may well be that you've simply exhausted the media. Testing to see whether your tank's pH is a result of absorbed CO2 is relatively simple if you have a calibrated pH meter/pen. Pull a cupful sample out of your tank, and measure the pH. Then place the sample outside, and bubble air through it for 10 minutes with an air pump. Then re-check the pH. If the difference between these two measurements is over 0.2 pH units, then either the inside of your home has a good deal more CO2 in the air than the outdoor air, or your tank is not in equilibrium with the indoor air from insufficient gas exchange, or both.

Another explanation for the week-long pH drop that you've observed is that your system has generating a good deal of organic acids into the tank water (from decay), and your water change is diluting some of this, which results in a pH rise.

That is good info. The observation that I noted with the Trident was more that I've noticed that as my pH declines so does my alk consumption. I know that is not the Trident doing that, I see it as more of a sign something is not right in the tank.

In terms of the organic acid from decay in the tank, would that be measurable in terms of po4 or no3? Or is that before it breaks down into those?

I have been replacing my co2 removal media as it changes colors, which is approximately every other week. I have the incoming air through the reactor coming from my skimmer cup which seems to make the media last a bit longer. However, it seems that replacing the media sites not usually result in much if any rise in pH.

I will test the water as you said as well and see what happens later tonight.

 

[Bastray]

A few comments -

Your trident, if operating correctly, will not change its dosing based on the tank's pH. The trident, and other similar auto-titrators, uses an automated version of the typical laboratory alkalinity titration. And while that method uses a pH probe to correctly determine the end point of the titration, there's going to be very little difference between the total amount of acid added (which is an estimate of the alkalinity) when the pH starts at 8.3 and when it starts at 7.6.

You mention that you have a "CO2 reactor" - I'm going to assume that means a CO2 removal reactor. If that's correct, is the adsorption media one of the indicating types (i.e., turns blue when exhausted)? If it isn't, then it may well be that you've simply exhausted the media. Testing to see whether your tank's pH is a result of absorbed CO2 is relatively simple if you have a calibrated pH meter/pen. Pull a cupful sample out of your tank, and measure the pH. Then place the sample outside, and bubble air through it for 10 minutes with an air pump. Then re-check the pH. If the difference between these two measurements is over 0.2 pH units, then either the inside of your home has a good deal more CO2 in the air than the outdoor air, or your tank is not in equilibrium with the indoor air from insufficient gas exchange, or both.

Another explanation for the week-long pH drop that you've observed is that your system has generating a good deal of organic acids into the tank water (from decay), and your water change is diluting some of this, which results in a pH rise.

Here is my Apex snap shot. Right after water change last week my alk consumption was around 90ml with a pH around 8.2. This is my current state a day before water change a week later.

 

[Dkeller_nc]

Thinking about this, there's at least one other explanation for a spike in alk & Ca consumption for a few days after a water change. And that would be if the change water is significantly lower in alkalinity & Ca than your trident's set point. I don't have a trident, so I can't answer this definitively, but I'd assume that the trident has some safeties built into the software to limit the amount of alk and Ca added to the tank even if the unit senses that the alk and Ca is significantly less than the setpoint.

That really doesn't explain the pH issue, though.

 

[Bastray]

Thinking about this, there's at least one other explanation for a spike in alk & Ca consumption for a few days after a water change. And that would be if the change water is significantly lower in alkalinity & Ca than your trident's set point. I don't have a trident, so I can't answer this definitively, but I'd assume that the trident has some safeties built into the software to limit the amount of alk and Ca added to the tank even if the unit senses that the alk and Ca is significantly less than the setpoint.

That really doesn't explain the pH issue, though.

I measure the water change water every time I do a water change and it matches the tank spot on. I keep my tank at the same parameters as my salt mix to prevent this from happening.

 

[Dkeller_nc]

Curious - did you perform the excess CO2 test (testing tank water, bubbling air through it outside, and retesting)? The issue you've described is quite puzzling, and there's at least a few of us that are intrigued by mysterious problems. And gratified by hopefully solving it and learning something!

 

[Randy Holmes-Farley]

I don't think it is related to the air in my house or the normal stuff that lowers pH. My pH used to rarely drop below 8. Now it goes down to 7.6 often. The tank is just not right and something is off. Just can't figure out what is off.

If the alk is stable, either the CO2 is changing, or the measurement is in error.

 

[Bastray]

It is a CO2 issue. It's been nice out the last 2 days and my windows have been open and pH has gone up to 8.32 at the highest yesterday. My Alk is less than stable though. I have increased my 2 part by 50ml a day. It has dropped a full point since the pH has increased. It was around 8.3 and it is currently sitting at 7.3. I am letting the Trident slowly bring it back up. I just need to figure out how to keep pH up when windows are closed. My CO2 scrubber does not seem to be doing a great job.

 

[Bastray]

Also, I don't care so much what my exact pH ends up being, just looking to keep it somewhat stable as it seems to be affecting my alk consumption pretty dramatically. I am not chasing a particular pH number.

 

[Spitty]

Is your skimmer pulling air from inside your house or fresh air from outside? I hooked up my skimmer to pull in outside air and it raised my ph and made it more stable.

 

[Bastray]

Is your skimmer pulling air from inside your house or fresh air from outside? I hooked up my skimmer to pull in outside air and it raised my ph and made it more stable.

Comes from in my house. It is not that close to a window and no way my wife is letting me run a tube across the room or drill into a wall to bring fresh air into my skimmer. Lol. I'm trying to get her to approve drilling a hole in my floor for auto water changes and I'm not being met with kindness and understanding on that. Lol

 

[Spitty]

Haha, I got you, but if you can sneak an airline outside it can be helpful. Lol