What pH do you run?

[ptreef]

As I’m working on dialing in my parameters, I’ve thought more about pH. I don’t currently test it. What does everyone try to keep?

Also thinking about my alkalinity dosing, I currently use sodium bicarbonate and understand that different types are better for higher or lower pH systems. Thoughts?

 

[BlackLitez]

8.1-8.3

 

[jcook54]

I don't really test for pH much. I dose and test for Alk and if that's good, the pH settles where it does. I test for it once in a while, similar to Magnesium. Both are important but with pH I don't really do anything to change it. The test is to make sure it's in an acceptable range.

(This statement is ironic because I've been having high pH problems in my frag system and I'm about at my wits end on how to deal with it.)

 

[Xemreef]

My PH Very low 7.5

 

[BlackLitez]

My pH has also been reading high on my pinpoint(9+), but the battery was also dying. I'm hoping it was a battery issue instead of actually being that high. I read on R2R, where Randy-Holmes said that high pH is usually a testing error and most people shouldn't really worry about trying to fix high pH.

You don't want a low pH, goal should always be 8+.

Raising Alk will help bring your pH up. My pH was reading 7.4-7.8 for a while until I raised my Alk, and now pH is reading off the charts

 

[bg2311]

Average PH for our system is 8.29. We run the skimmer 24/7 on a recirculating CO2 scrubber with the air pulled through the skimmate locker. Display runs during the day, frag tank runs at night. This is to avoid the PH dip if both were off at night. Originally, the refugium ran at night. Now we've found the supplemental PH boost it provides is actually more useful during the day to even out the swing (frag tank lights are more intense). Max is around 8.32 with the fuge on during the day. If we run the fuge at night with the frag tank it can hit 8.34 (valve closes on the scrubber at that point to keep it from rising further).

We try to avoid more than a .1PH swing up or down. Alk is around 8.1 using ESV 2 part solution dosed in equal amounts 24/7. At about 180ml of each alk & calc per day.

If we turn our skimmer or flow off for any length of time there's a good dip in PH that lasts for a while before it comes back up again. You can see the dips in the graph when we turn off the skimmer and flow for feeding each day.

 

[timeconsumer]

If you want to run a little higher you can change from dosing sodium bicarbonate to dosing sodium carbonate which will cause slightly larger bumps in pH every time it is dosed. This benefit is only temporary as gas exchange with your surrounding air will bring it back to your baseline level shortly. You can use a dosing pump and timer to slowly meter it out throughout the day, or target times when your pH tends to be the lowest (night time perhaps) and capture as much of this benefit as possible but it will be subtle and not cause any massive changes.

If you want to take that concept a step further I would recommend switching over to kalkwasser dosing. Because kalk is hydroxide when you dose it to the system it causes a much larger pH bump compared to sodium carbonate or bicarbonate. There are a few considerations with dosing kalkwasser but overall it is not an overly complex thing for low or medium consumption tanks and can be easily done with a single dosing pump head, digital timer, and a reservoir. I dose 150ml of saturated kalk solution per day for my 20g mixed reef. For high consumption tanks it is more challenging to maintain calcium and alkalinity with only kalkwasser.

In the end the best way to permanently keep your pH high is you need to correct co2 levels in your ambient air. Some people accomplish this by using a co2 scrubber on their skimmer air intake line. Some people run an external air supply for their skimmer. Some people open a window. Some people fill their house with houseplants. There are a lot of ways to reduce ambient co2 in your home or in your tank that can result in running a higher pH.

 

[jcook54]

There's an old toungue-in-cheek saying - "Here, take my advice, I'm clearly not using it!" and that about sums up my current pH situation. For years and years I've advocated for a good Calcium/Alk balance and letting the pH be what it's going to be. This assumes it's in an acceptable range of course. My display tank runs around 7.9 and it has for years and years. With my frag system showing high pH, I'm currently ignoring my advice and starting to worry about it.

I realized just now that I didn't really answer your original question. I shoot for a pH of 8.3 but have never really been there exactly. pH fluctuates and it will swing quite a lot as the lights cycle on and off. I've attached a screenshot of my pH for the frag tank so you can see how much it really does change.

 

[BlackLitez]

I'm also usually swinging within 2-3 points, so jealous that @bg2311 has it down to half a point at the desired 8.3. Perfection!

 

[Adam]

I don't advocate "Chasing numbers" either. But in my mind chasing is adding something or doing something that the system doesn't already need to hit a specific number. I like to keep my Alk at 8.5-9. There's several products you can dose to get it there.(Excluding calcium reactors) These are listed from the lowest to highest pH impact. Baking soda (Sodium Bicarbonate) 8.5pH; Soda Ash (Sodium Carbonate) 11.6pH; Kalk (Calcium Hydroxide) 12.8pH; and finally Lye (Sodium Hydroxide) 14pH. I highly recommend dosing smaller amounts frequently over 24hrs and this becomes more important the further you move from left to right on the list. It's also important to know the safe mixing and handling of each. Baking soda is pretty damn safe, Lye not so much.

All of those are the lest expensive way to deal with pH. Depending on the time of year you may need to choose a different one. But if none of them work you might want to look at a co2 scrubber. The media is costly although it can be minimized somewhat using a closed loop setup like @bg2311

Personally I feel that most of the time properly dosed Kalk is the best and lest expensive option most often and it adds your calcium too. That is until you reach the point that you can't add anymore because you've reached the evaporation rate of the tank. If/when you get there, you will know you are a successful reefer!!!

 

[bg2311]

I don't advocate "Chasing numbers" either. But in my mind chasing is adding something or doing something that the system doesn't already need to hit a specific number. I like to keep my Alk at 8.5-9. There's several products you can dose to get it there.(Excluding calcium reactors) These are listed from the lowest to highest pH impact. Baking soda (Sodium Bicarbonate) 8.5pH; Soda Ash (Sodium Carbonate) 11.6pH; Kalk (Calcium Hydroxide) 12.8pH; and finally Lye (Sodium Hydroxide) 14pH. I highly recommend dosing smaller amounts frequently over 24hrs and this becomes more important the further you move from left to right on the list. It's also important to know the safe mixing and handling of each. Baking soda is pretty damn safe, Lye not so much.

All of those are the lest expensive way to deal with pH. Depending on the time of year you may need to choose a different one. But if none of them work you might want to look at a co2 scrubber. The media is costly although it can be minimized somewhat using a closed loop setup like @bg2311

Personally I feel that most of the time properly dosed Kalk is the best and lest expensive option most often and it adds your calcium too. That is until you reach the point that you can't add anymore because you've reached the evaporation rate of the tank. If/when you get there, you will know you are a successful reefer!!!

The CO2 scrubber addition to the skimmer made a big difference in the PH boost but it would be prohibitively expensive to replace the scrubber media without a recirculating loop setup. Before we added the closed loop the PH boost lasted about a week before it dipped again and we had to replace the media. If you buy media in bulk and not branded for reef tanks you can get it cheaper. The closed loop means it lasts much long so we only have to change it every month or so and it also increases the PH boost further than the scrubber alone. Part of setting up the closed loop was adding the DIY skimmate locker. Not having to empty the skimmer but once every 6 months has been nice.

 

[ptreef]

Thank you for everyone’s input! Those were much more technical responses than I was expecting.
Here’s a new scenario/question along those lines, and this is without testing my pH at all.
I dose approximately 400ml of sodium bicarbonate per day. I do have a large system with some large corals, but does this seem abnormally high? Should I consider changing media if it requires that much of sodium bicarbonate? My alk has been low, I’m working on bringing it back from 6.9 towards 8.0 again. Currently testing 7.7dkh today

phosphate 0.09-0.12 lately
Nitrate 2.0-3.0ppm

 

[BlackLitez]

Having your Alk that low is most likely the reason you are experiencing low pH. Once you get it up and stable, the pH should balance out.

 

[gill]

I dose Alk to try to keep it at 8.0 (but I hand dose, every few days). PH probably goes from 7.8 to 8.1 during a 24 hour cycle. My SPS are adding volume like mad, so I am not concerned with PH being less than "ideal".

 

[56cbr600rr]

There's an old toungue-in-cheek saying - "Here, take my advice, I'm clearly not using it!" and that about sums up my current pH situation. For years and years I've advocated for a good Calcium/Alk balance and letting the pH be what it's going to be. This assumes it's in an acceptable range of course. My display tank runs around 7.9 and it has for years and years. With my frag system showing high pH, I'm currently ignoring my advice and starting to worry about it.

I realized just now that I didn't really answer your original question. I shoot for a pH of 8.3 but have never really been there exactly. pH fluctuates and it will swing quite a lot as the lights cycle on and off. I've attached a screenshot of my pH for the frag tank so you can see how much it really does change.

I'm exactly like yours but 7.8-8.1 daily fluctuations.

Without adding equipment, not sure what to do to up it somewhat..

 

[BlackLitez]

I'm exactly like yours but 7.8-8.1 daily fluctuations.

Without adding equipment, not sure what to do to up it somewhat..

i don't recommend doing anything to up it.

i think that's an acceptable range. Rather than up it, think more about how to stabilize it, reduce the swings.

imo, the only time pH should be actively "corrected", is if it's like 7.4