Help.. PH is very high ( 8.6)

[Deep]

Hello,
I wanted to get some advice about my PH and what I need to do if I have to lower it. The tank, a RedSea Reefer 250 (60 gallons) is about 10 months old. Earlier I was running 2 Kessil A360 led. I recently changed to a 250 W MH with T5. Parameters are ALK 7.5, Cal 480, Mg 1300 No3 2 ppm Po4 0.2 ppm.
I dose Aquaforest component 1,2,3 using a doser.
The tank being fairly news has mostly Acropora Frags and 3 small Clams. Lightly stocked in terms of Fishes. But Alk usage is fairly high ( about .8 to 1 dkh used in 24 hours)

When I used to run LED till a month ago my PH was in the 8.0 to 8.2 range. I used to carbon dose using Nopox daily 6ml and run DR Tims NP Bio-pellets. Ever since I switched the lights over to the MH my PH has climbed to 8.63 during the day and 8.24 in the night. I did not stop using Nopox initially and still saw the high levels of PH. But last few days my Nitrates , Phosphates dropped to close to Zero so I have had to stop the carbon dosing and dose nitrates and phosphates ( Seachem flourish nitrogen and Phosporous).

I have not modified my flow or added new pumps or wavemakers.

At this point I am running my Skimmer 24 hours ( as I always have). I am not running any reactors at this point. I run a 11 W UV and carbon in a bag.

A couple of days back I setup a small ( 7 gallon) Chaeto refugium.

Do I need to reduce my PH by adding CO2 ? If so whats the best way to do that ? I do not want to invest in a calcium reactor as I am happy with the 3 part dosing.

The spike you see below to 8.8 one of the days is when I calibrated my Apex Neptune PH probe because I thought my probe had lost calibration. But the high PH was noted even after calibration.

 

[Reef - Tripp]

Chaeto light is 24/7

 

[Deep]

Chaeto light is only on in the night.

 

[Pistondog]

I'd verify your ph measurement with a 2nd source.
Seems like Randy said above 8.5 is difficult unless something is overdosed.

 

[taricha]

The only way that pH is possible at alk of 7.5 is if there were a stupid-low out of balance CO2. Like way less than indoor or even outdoor.
Is that possible? Only if there is very poor gas exchange and a lot of photosynthesis.
That seems much less likely than incorrect reading.

As Randy has recommended, take a cup of tank water. Bubble it with an airstone (pulling outdoor air - known CO2 - would be more informative).
If it drops back significantly, then the issue is aeration - increase gas exchange.
If the pH still shows higher than that alk merits, then fix the pH meter.

 

[EMeyer]

You mentioned calibration, any chance your calibration solutions are old? I've occasionally seen weird results with very old calibration standards. At your (perfectly normal) alkalinity it seems unlikely the value could be accurate, and pH meters can do funny things if damaged or miscalibrated.

 

[Deep]

As user taricha suggested, at around 4 pm ,before my halides go off and PH is usually the highest, I took a cup of water from the tank and aerated it. I placed the probe in the cup as it was being aerated from an airpump (outside the cabinet). Over 20 mins the PH dropped from around 8.6 to 8.4. So it does look like lack of CO2.

 

[Deep]

You mentioned calibration, any chance your calibration solutions are old? I've occasionally seen weird results with very old calibration standards. At your (perfectly normal) alkalinity it seems unlikely the value could be accurate, and pH meters can do funny things if damaged or miscalibrated.

I bought the fluids recently but cannot rule out possibility that it may have been lying in the store for long. So will get new ones and calibrate again.

 

[EMeyer]

I bought the fluids recently but cannot rule out possibility that it may have been lying in the store for long. So will get new ones and calibrate again.

To be clear, I've only seen them go bad once opened. Somebody with more chemistry than me can chime in on whether they can go bad while sealed. If you calibrated recently with newly opened standards, that should be good enough. Puzzling.. I've never seen a pH that high in a reef tank.

 

[mitch91175]

As user taricha suggested, at around 4 pm ,before my halides go off and PH is usually the highest, I took a cup of water from the tank and aerated it. I placed the probe in the cup as it was being aerated from an airpump (outside the cabinet). Over 20 mins the PH dropped from around 8.6 to 8.4. So it does look like lack of CO2.

Nothing scientific, but your metal halides I believe is what is contributing to having a much higher pH. I see the exact same thing you are with my pH on the Apex and I am also running MH. When the MH turn on, pH skyrockets to its peak and once the MH turn off, pH begins to drop soon after.

I am not as high, but seems the coral like it with the increased consumption I am noticing.

 

[Deep]

Nothing scientific, but your metal halides I believe is what is contributing to having a much higher pH. I see the exact same thing you are with my pH on the Apex and I am also running MH. When the MH turn on, pH skyrockets to its peak and once the MH turn off, pH begins to drop soon after.

I am not as high, but seems the coral like it with the increased consumption I am noticing.

Good to know that it is not just me. I also think it is due to the increased photosynthesis by the corals when the halides are on, but wondering if I can help the situation by adding some C02 using soda water or something. Randy in his article suggests soda water or Vinegar.

http://reefkeeping.com/issues/2005-03/rhf/

 

[AcanthurusRex]

IMO you’re already adding to many things to the water. Do a series of water changes if you think the water is out of balance.
I don’t think you’re PH reading is accurate.
Glad we acknowledge that there is no scientific evidence to support the notion that MH are the cause elevated PH. The MH might have something to contribute to photosynthesis.

 

[Randy Holmes-Farley]

This is not an emergency, IMO. It may not be a problem at all.

Assuming the pH is accurate, switching carbonate dosing to bicarbonate will help, as will more aeration, if you want the pH peak to come down.

 

[Deep]

This is not an emergency, IMO. It may not be a problem at all.

Assuming the pH is accurate, switching carbonate dosing to bicarbonate will help, as will more aeration, if you want the pH peak to come down.

Thank you Randy. Yes the PH is accurate. I recalibrated and tested the probe by placing it in a PH calibration solution and it reads the correct value.
I have prepared a solution with Baking soda and will start dosing with that. But as you point out in your article it is probably a poor way of lowering PH. In that article you suggest Vinegar as well , so maybe I will give that a try when I managed to raise my nutrients sufficiently.

Thank you for your help.

 

[Deep]

IMO you’re already adding to many things to the water. Do a series of water changes if you think the water is out of balance.
I don’t think you’re PH reading is accurate.
Glad we acknowledge that there is no scientific evidence to support the notion that MH are the cause elevated PH. The MH might have something to contribute to photosynthesis.

The reading is accurate, the probe placed in a calibration fluid reads the value of the fluid correctly. I dont think water changes is going to help.

 

[Randy Holmes-Farley]

If pH 8.6 is accurate, then more aeration alone will lower it.

 

[jphilip813]

If pH 8.6 is accurate, then more aeration alone will lower it.

More areation, how do you to that? I am also having a spike...in the last week or so...8.50 daily...wjhen I am normally 8.25-8.31

 

[Randy Holmes-Farley]

More areation, how do you to that? I am also having a spike...in the last week or so...8.50 daily...wjhen I am normally 8.25-8.31

Airstone? Skimmer? Bigger skimmer? Open tank hood? open sump top?

pH 8.5 daily is fine though. Mine routinely hit that level each day.

I'd also recalibrate the pH meter. Sudden changes may be test error.

 

[jphilip813]

Airstone? Skimmer? Bigger skimmer? Open tank hood? open sump top?

pH 8.5 daily is fine though. Mine routinely hit that level each day.

I'd also recalibrate the pH meter. Sudden changes may be test error.

Ok thank you, I actually adjusted the water level for my skimmer as recommended 8-9" and the ph dropped to around the 8.20 -8.35...weird, but who knew. I had the skimmer at the same level since May and then recently the ph started to skyrocket. But also I do need to recalibrate the probes...ots being a long time...(more than 6 months)