Tested pH with lab pH meter and it's 7.5!

[KonradTO]

Your outdoor aeration lest.

Also, that salt pH is still dependent on CO2 levels. So as it mixes and aerates, it will try to equilize with the CO2 in the air.

For the aeration test I did the following:
-Measured pH of 60 ml of sample water
-Took the main container of the water sample and areated outside for 1h open with air pump
-closed lid and left at room temp for 1h
-measured 60 ml of areated water

 

[arking_mark]

For the aeration test I did the following:
-Measured pH of 60 ml of sample water
-Took the main container of the water sample and areated outside for 1h open with air pump
-closed lid and left at room temp for 1h
-measured 60 ml of areated water

You need to measure immediately after aeration...

 

[Adam1985]

Many people are successful with SPS without boosting pH.

Fully agreed. You don’t need to give up on anything!

And I’m with Mark, have spent a lot of time on pH and it’s been fun. But has it made a difference? I like to think so but can’t prove it.

So while I think we can get you to your desired numbers, I just am concerned you’re not being able to enjoy your tank.

 

[KonradTO]

Fully agreed. You don’t need to give up on anything!

And I’m with Mark, have spent a lot of time on pH and it’s been fun. But has it made a difference? I like to think so but can’t prove it.

So while I think we can get you to your desired numbers, I just am concerned you’re not being able to enjoy your tank.

OK I get your point. Sooner or later I'd like to find out how is it possible I have such numbers anyway though. Especially if it's because of very high co2 in my flat

 

[Adam1985]

@KonradTO how you doing? Any new findings?

Actually I have an interesting observation from my system to share. Maybe it will be interesting for you or others as it’s related to macro growth, pH, CO2 levels, nutrients, and alkalinity. I’ll probably post for some advice as well a bit later.

Basically I was skimmerless for a couple of weeks after removing my previous skimmer to prepare the sump for a skimmer upgrade and observe how the tank would be skimmerless. My alkalinity is high; around 11.

I’m now running the new skimmer but I haven’t connected my CO2 scrubber. What I’ve seen is the macroalgae is suddenly not doing well, and pH is lower still (8.1-8.2) suggesting my skimmer is certainly driving more CO2 from household air into the water column than would be coming in without skimming. Funny thing is nutrients aren’t terribly low now either; around .1 ppm PO4 and 7-9 ppm NO3. I plumbed the skimmer in via a modified Triton approach but recirculating water in the sump (skimmer feed pulls a portion of water post refugium to skimmer, and skimmer effluent goes in back before the refugium). This was due to space reasons and desire to get household CO2 to the refugium.

So the question in my case is what’s messing with the macroalgae? It’s one or more of the following as other variables are unchanged. Too much flow through the refugium? Nutrients too low? Or the new gas/liquid equilibrium is somehow impacting the algae? I’ve been feeding more heavily to try and keep plenty of nutrients available and would assume my current nutrient levels are high enough. I have kept up my regular iron dosing, trace dosing, phyto feeding, etc.

I’m considering what to test next; turning the skimmer off when refugium lights are on, or turning the skimmer off full time again. Also considering when to hook up my CO2 scrubber.

Anyway bottom line for your original topic is just keep in mind that a skimmer with no CO2 scrubbing will drive your pH even lower if having your water being closer to equilibrium with household air also means a higher CO2 concentration.

 

[Adam1985]

Just one more experimental data point supporting all we’ve discussed; reconnected my CO2 scrubber 18 hours ago and pH is now back to 8.5…

 

[Randy Holmes-Farley Verified Community Expert]

I’m now running the new skimmer but I haven’t connected my CO2 scrubber. What I’ve seen is the macroalgae is suddenly not doing well, and pH is lower still (8.1-8.2) suggesting my skimmer is certainly driving more CO2 from household air into the water column than would be coming in without skimming.

That was certainly the case with my skimmer.

When it went offline for a few weeks as an experiment, the average pH rose. In my case, it rose too much (I also use limewater).

That said, a skimmer can raise or lower the pH, and may do different things at different time of the day (raising the nightly low and lowering the daily high, for example).

 

[gbroadbridge]

Anyway bottom line for your original topic is just keep in mind that a skimmer with no CO2 scrubbing will drive your pH even lower if having your water being closer to equilibrium with household air also means a higher CO2 concentration.

I'm not sure I understand what you mean.

Running a skimmer will drive the CO2 level in your tank to equilibium with the air intake of the skimmer. The faster the pump, the faster it will do it.

If you are running soda lime in the intake line to your skimmer, the soda lime will remove co2 which will eventually cause the pH of the tank to rise.

I'm not a chemist so I don't understand the processes involved in the chemical process - always happy to learn.

I learn something new every day.


Regards,
Graham.

 

[Randy Holmes-Farley Verified Community Expert]

I'm not sure I understand what you mean.

Running a skimmer will drive the CO2 level in your tank to equilibium with the air intake of the skimmer. The faster the pump, the faster it will do it.

If you are running soda lime in the intake line to your skimmer, the soda lime will remove co2 which will eventually cause the pH of the tank to rise.

I'm not a chemist so I don't understand the processes involved in the chemical process - always happy to learn.

I learn something new every day.


Regards,
Graham.

The statement you quoted that a skimmer will drive pH "even lower" is not always true, but it is sometimes true.

Even with soda lime the pH doesn't always rise (e.g., if the tank is already deficient in CO2 (high pH), it may keep lowering it)

In general, the skimmer drives the effluent water toward equilibrium with the CO2 level in the air entering the water. That can be up, down, or no change at all. As noted above, it can do different things at different times of day as the tank and room CO2 levels vary.

 

[SlugSnorter]

Just a heads up: be careful to take it slow, many other params are tied to PH and vice versa, using a product to change one can through the others out of wack

 

[KonradTO]

@KonradTO how you doing? Any new findings?

Hi Adam! The tank is doing good. I stopped measuring pH at some point a couple of weeks ago after I dosed some sodium carbonate to raise kH to 10-11, last time I measured was around 7.7 so I decided it was fine the way it was (I have a lot of coralline growth so it should be ok). I increased gas exchange and built a DIY ato to compensate for evaporation, even though I am not super happy about this, it is another instrument that might fail.

Actually something funny happened recently. I left for holidays one week and the ato did not work properly, so salinity increased a bit. Right before I left last week PO4 were around 0.1 and NO3 around 10-15 ppm.
All the macro grew incredibly fast in this week, especially the Caulerpa prolifera, where the blades grew HUGE (15 cm long x 2cm wide). Caulerpa brachypus on the other hand seems its growing smaller blades than usual, which is good news, as it is harder to control.
I added finally the led fixture and this week I will add some corals. Let's see how the situation goes with Ca, Mg and Alk consumption from those, I expect I will have to keep in check kH even more often.
As soon as I have time I will re-measure pH and nutrients.

So the question in my case is what’s messing with the macroalgae? It’s one or more of the following as other variables are unchanged. Too much flow through the refugium? Nutrients too low? Or the new gas/liquid equilibrium is somehow impacting the algae? I’ve been feeding more heavily to try and keep plenty of nutrients available and would assume my current nutrient levels are high enough. I have kept up my regular iron dosing, trace dosing, phyto feeding, etc.

I’m considering what to test next; turning the skimmer off when refugium lights are on, or turning the skimmer off full time again. Also considering when to hook up my CO2 scrubber.

Anyway bottom line for your original topic is just keep in mind that a skimmer with no CO2 scrubbing will drive your pH even lower if having your water being closer to equilibrium with household air also means a higher CO2 concentration.

my impression is that plants and animals in the tank get used to some conditions along some time. When you keep it untouched they thrive but as soon as we change something they need some time again to acclimate to the new conditions.
Regarding CO2 in my system, it is hard to test how it would change with a skimmer, if it would increase or decrese my pH, giving that I have literally no space for the skimmer at the moment. What I can do at some point if I have problems with SPS corals is to measure my flat CO2 concentration with a CO2 sensor and then take the lid off while running a bubble scrubber and follow the pH trend. I am building a reefpi system with the Robotank, which will include certainly a pH probe, so it will be easier to experiment a bit how pH changes depending on other factors.

 

[Adam1985]

I'm not sure I understand what you mean.

Running a skimmer will drive the CO2 level in your tank to equilibium with the air intake of the skimmer. The faster the pump, the faster it will do it.

If you are running soda lime in the intake line to your skimmer, the soda lime will remove co2 which will eventually cause the pH of the tank to rise.

I'm not a chemist so I don't understand the processes involved in the chemical process - always happy to learn.

I learn something new every day.


Regards,
Graham.

Sorry for any confusion! I just meant if in a situation where running a skimmer would result in a higher CO2 concentration in your water, and all other things remain constant, pH should decrease.

Agree with Randy’s follow up clarification.

Thanks all! We’re all learning something every day, that’s what keeps it interesting.

 

[Adam1985]

The statement you quoted that a skimmer will drive pH "even lower" is not always true, but it is sometimes true.

Even with soda lime the pH doesn't always rise (e.g., if the tank is already deficient in CO2 (high pH), it may keep lowering it)

In general, the skimmer drives the effluent water toward equilibrium with the CO2 level in the air entering the water. That can be up, down, or no change at all. As noted above, it can do different things at different times of day as the tank and room CO2 levels vary.

Perfectly stated!

 

[Adam1985]

Hi Adam! The tank is doing good. I stopped measuring pH at some point a couple of weeks ago after I dosed some sodium carbonate to raise kH to 10-11, last time I measured was around 7.7 so I decided it was fine the way it was (I have a lot of coralline growth so it should be ok). I increased gas exchange and built a DIY ato to compensate for evaporation, even though I am not super happy about this, it is another instrument that might fail.

Great to hear! Makes sense and I’ve somewhat reduced testing myself over time, as I decided that the time testing was not adding value and I’d rather use that time to enjoy my tank. Now I test 1-2 times per week for record keeping but anything more, my requirement is that I only will test if I have an action I’ll take or not take based on the result.

ATOs are useful but do fail; but there are ways to protect against failure as well. Long ago I had a few gallons of kalkwasser go in over less than an hour which created some issues as you’d imagine. Fortunately almost all my inhabitants survived. Now my ATO fill rate is restricted heavily, I don’t dose anything via the ATO, and a high level sensor will also kill power to it if tripped.

Actually something funny happened recently. I left for holidays one week and the ato did not work properly, so salinity increased a bit. Right before I left last week PO4 were around 0.1 and NO3 around 10-15 ppm.
All the macro grew incredibly fast in this week, especially the Caulerpa prolifera, where the blades grew HUGE (15 cm long x 2cm wide). Caulerpa brachypus on the other hand seems its growing smaller blades than usual, which is good news, as it is harder to control.
I added finally the led fixture and this week I will add some corals. Let's see how the situation goes with Ca, Mg and Alk consumption from those, I expect I will have to keep in check kH even more often.
As soon as I have time I will re-measure pH and nutrients.

This sounds great. So nice to return home to impressive growth rather than the opposite. Congratulations on your lighting and pending coral additions!

my impression is that plants and animals in the tank get used to some conditions along some time. When you keep it untouched they thrive but as soon as we change something they need some time again to acclimate to the new conditions.

This makes sense to me and I need to practice what I preached, as always am coaching new people to not tinker too much and change too much too quickly, and don’t fix what’s not broken. Secret to success is keeping your hands off of and out of your tank. But you know, easier said than done. Plus I’m an engineer so fixing what’s not broken is sort of in my DNA now, but can be a bane to success.

Regarding CO2 in my system, it is hard to test how it would change with a skimmer, if it would increase or decrese my pH, giving that I have literally no space for the skimmer at the moment. What I can do at some point if I have problems with SPS corals is to measure my flat CO2 concentration with a CO2 sensor and then take the lid off while running a bubble scrubber and follow the pH trend. I am building a reefpi system with the Robotank, which will include certainly a pH probe, so it will be easier to experiment a bit how pH changes depending on other factors.

This makes sense and the Reefpi sounds great; I really think your SPS will also be fine without a skimmer if you can successfully manage nutrients via macroalgae. Also for your indoor air, the airstone test could give you an idea of the relative CO2 levels but of course won’t give you a number.

Great to hear things are going well and good continue