PH Issues

[JustinGr]

I have a new tank, it's a custom 80 with a sump that holds 40 gallons. It has an Apex on it (brand new) and the PH reads 7.7 to 7.9 over the course of the day. I've calibrated the probe numerous times, and used a Hannah PH test kit to compare it, and if the tank shows 7.84, Hannah will show 7.9, and if I quickly test again with the Hannah, it will show either .02 +/- from the first reading, so I believe the Apex probe is fairly accurate .

Now, if I test Mag, it is 450-500, and Alk was 9. If I dose Baked Baking Soda, it will cause a quick PH bump to 8.15 and within an hour it is back to 7.8x. Some days the solution will just cause snow.

I have a Cor-15 pump at 50% speed, meaning I am turning over the take about 7-8 times per hour. I have a Nero 7 Powerhead on 70% on Random modes. The Sump has a dual tray dump style Algal Turf Scrubber. Each side of the dump tray holds about 20 ounces of water that splashes down into the sump, so, I think, I have plenty of aeration. I even put the return nozzle to blow the return water onto the surface of the water of the tank, thinking I need more surface to air contact for CO2 exchange, but even doing this for 24 hours made no appreciable difference.

The ATS light is on for 12 hours, opposite the take light schedule with just 30 minutes of overlap between the two lights.

My main concern is that the PH is dropping into the low 7.7's, and this morning it was 7.71 at or around 4am when the Apex texted my phone with the alarm for PH out of my control zone.

Tank has been up for 4 weeks, two fish, and 100# of base rock and 30# of cultured live rock. All other tests show the tank is stable, so, the PH has me confused. There is no large bio-load of waste that would cause this, not that I can tell. I change my filter socks every three days, don't over feed the two clowns. I'm lost.

Do I just leave it be? I don't want to chase something that can't be caught.

I use RO/DI and the TDS meter shows zero on the output. I used Red Sea salt mix, if that matters.

 

[wvned]

The unseen factor in tank pH is how much CO2 is in the air inside your dwelling. CO2 dissolves in water and becomes carbonic acid. This happens continuously but our closed homes often concentrate CO2 inside so it is much higher than free air. As your tank ages the buffering capacity will increase some. You can ventilate the area of the tank with an open window and many of us run an outside air source to our skimmers. Some people recirculate the air in their skimmer through CO2 scrubbing media.

I use kalkwasser (pickling lime dissolved in water) like you are using soda ash (baked baking soda). kalkwasser adds both calcium and carbonate at the same time in balance while it also raises pH. You can only add so much because you can't raise calcium and alk to infinity.

5 Tips to Raise pH in a Reef Tank - ReefBum

 

[reefing102]

If that’s your true Mag reading, that seems very low. Typically Magnesium should be at least 1200 or so up to 1400. Mg, Ca and Alk and Ph too my knowledge are all inter related. As is CO2 as @wvned mention. Low Mg could be the result of low salinity (just a thought).

 

[kharmaguru]

Now, if I test Mag, it is 450-500, and Alk was 9. If I dose Baked Baking Soda, it will cause a quick PH bump to 8.15 and within an hour it is back to 7.8x. Some days the solution will just cause snow.

Mag has to be test error or you actually meant calcium? Precipitation events (the snow) will just work against your alk and PH. Sounds like you are dosing manually? Dose slowly and in an area of good water motion to prevent precipitation (proper level of magnesium is also necessary). As @wvned said, CO2 is your biggest PH factor and if you can manage that, you are better off.

 

[wvned]

Low magnesium allows precipitation of calcium and carbonate. You are adding carbonate. You need to test your calcium. It is being precipitated out and you aren't adding it back.
Also your magnesium needs to be higher.

 

[reefing102]

Ooo I’m saving that for later

 

[griss]

Ooo I’m saving that for later

It’s on BRS’ website. I printed it from there and laminated it to keep by my tank.

 

[JustinGr]

Mag has to be test error or you actually meant calcium? Precipitation events (the snow) will just work against your alk and PH. Sounds like you are dosing manually? Dose slowly and in an area of good water motion to prevent precipitation (proper level of magnesium is also necessary). As @wvned said, CO2 is your biggest PH factor and if you can manage that, you are better off.

Yes, my fault, I was referring to Calcium and my brain typed Mag. My mag is a little over 1200. I left all windows open today and added an extra power head to agitate the surface. The PH did not move at all. My house is 6000+ square feet and two people live here and I can’t imagine my house is over saturated with CO2. But I will air it out again tomorrow and keep at it. I keep dosing Alk in an attempt to keep the PH over 7.7-7.8 but it only helps for a few hours and it crashes back down.

I ordered the Trident and DOS system to get a handle on the testing/dosing. Hopefully that will help. Thanks for the chart and advice. I am deeply appreciative of everyone answering.

 

[kharmaguru]

Yes, my fault, I was referring to Calcium and my brain typed Mag. My mag is a little over 1200. I left all windows open today and added an extra power head to agitate the surface. The PH did not move at all. My house is 6000+ square feet and two people live here and I can’t imagine my house is over saturated with CO2. But I will air it out again tomorrow and keep at it. I keep dosing Alk in an attempt to keep the PH over 7.7-7.8 but it only helps for a few hours and it crashes back down.

I ordered the Trident and DOS system to get a handle on the testing/dosing. Hopefully that will help. Thanks for the chart and advice. I am deeply appreciative of everyone answering.

You shouldn't try to correct PH with ALK adjustments. Target a specific Alkalinity and stay there - that's the best for the health of your system. Adding kalkwasser to your top off water can be helpful but perhaps your PH test is dodgy? I agree, 2 people over 6000 sq/ft does not make alot of CO2, unless you have an army of dogs.

 

[wvned]

On a new tank 7.8 or so seems to be the number for a while.

 

[JustinGr]

You shouldn't try to correct PH with ALK adjustments. Target a specific Alkalinity and stay there - that's the best for the health of your system. Adding kalkwasser to your top off water can be helpful but perhaps your PH test is dodgy? I agree, 2 people over 6000 sq/ft does not make alot of CO2, unless you have an army of dogs.

Just 4 little dogs. 2 have decided the 2nd floor is their domain and 1 loves the 3rd. The last one is my shadow. I’ll target the numbers and hope the PH moves along.

 

[Vinny Kreyling]

PH tends to do whatever it wants to do, even if we intervene.

 

[af4evr13]

I am definitely no expert here but I bought a cheap Carbon Dioxide tester for my house and found that my home was about 500ppm higher than my outside air. I don't have great ventilation and the AC unit is in the basement with no outside air being introduced. So it was recommended to me on this forum to run a line to my skimmer that goes outside. In just two days I went from 7.8 consistent to 8.2 and holding steady. So this worked for me and huge thank you to all on this forum for the help!

 

[JustinGr]

Update. I put a C02 scrubber on the skimmer. It stabilized the PH to a high of 8.0 around 3pm to a low of 7.92 at 6am. But I can’t get it higher. Alk is at 8.78 and Cal is 455, and Mag is 1350 (Apex Trident). I’ve calibrated the Apex PH probe and tested with Hanna. It’s the same. Thoughts?

 

[Jposch]

The unseen factor in tank pH is how much CO2 is in the air inside your dwelling.

And outside! In the upper midwest, there are a few of us getting alot of co2 from the wildfires. I get to see ph rise after it rains or decent winds. Before the fires started, 8.5-8.8ph was the norm, but lately, 8.1-8.4 is more typical. All the kalkwasser, turf scrubber running 18 hours a day, Outside air, 12:12 photoperiod. 2 month old probe, calibrated 3x and even switched to an older but good probe and same. Bubbled a container of tank water excessively outside and pH was still low. Been a real nightmare the last month or so. No end in sight.