Not getting much of a pH raise from CO2 scrubbers?

Treldeham

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I have two Bulk Reef Supply CO2 scrubbers hooked up in series to a Coralife 220G skimmer in a recirculating setup in my 180G FOWLR. Without them before the pH tended to be around 7.7 and I would use Seachem's Marine Buffer to raise it to the 8.2 range. I set up the CO2 scrubbers about two weeks ago, but my pH has only gone up to about 7.9. Is there something wrong I've done with my recirculating setup? I know my skimmer isn't the best, but I have a low bioload tank and it has done well enough. I can't take in air from the outside because of the positioning of my tank unfortunately. I have tried leaving a door open during the day (the tank is in the basement so no windows) to raise pH as well, but that didn't have an effect.

sump1.jpg sump2.jpg sump3.jpg
 

lapin

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Maybe Co2 in the air is not the issue. Maybe its your water. Have you done the test where you take water outside and aerate?
 
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Treldeham

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I've not heard of that, but I assume you take a pH reading of the water before and after aeration to see if it raises the pH? If it's not the CO2, then I'm not sure what else it could be.
 
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wom001

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Just for the health of my fish. I don't want to chase an exact number, but as long as it's in the 8.1 to 8.3 range I would be happy.
So your fish are displaying some discomfort, discomfort, or acting erratically? Or is everything acting / looking / swimming normally?

I ask this because a perfect PH range is a simplification of a range of figures that normally work for "most" fish. Since we have species from all over the world the "perfect" ph will vary from species to species thus that most quote. So unless your fish / corals / inverts are obviously affected I'm just not seeing the purpose of going after a specific PH range if everything is adapting to it and thriving...
 
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Gtinnel

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For what it's worth when I started pulling in air from outside for my skimmer I only gained about .2 also. Although mine went from 8.0 to 8.2. Assuming your CO2 scrubber is working as it should then pulling in outside air to the skimmer probably won't raise your pH. With you tank being FOWLR I wouldn't bother trying to raise it any more. Most people who aim for 8.2 are doing it to help with coral growth, the fish will be fine with the pH at 7.9.
 
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lapin

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Pure RODI water should be 7. The buffers in salt mix will raise it. Co2 in the air will lower it.
Like it was mentioned above 7.9 is fine
 
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LuisPerez711

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When I started using a CO2 scrubber I only got a .15 raise in my ph. Went from 7.8 - 8.1 to 7.95 - 8.22

I have a 120gal with a Nyos 160. I also set it up to recirculate the air from the cup back into the skimmer. I'm happy with it because my 2/3 part dosing boosts the ph a little higher.

I dont know if many people have seen a significant increase after attaching a CO2 scrubber but I could be wrong.
 
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Treldeham

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So your fish are displaying some discomfort, discomfort, or acting erratically? Or is everything acting / looking / swimming normally?

I ask this because a perfect PH range is a simplification of a range of figures that normally work for "most" fish. Since we have species from all over the world the "perfect" ph will vary from species to species thus that most quote. So unless your fish / corals / inverts are obviously affected I'm just not seeing the purpose of going after a specific PH range if everything is adapting to it and thriving...
All of the fish are in good health, but every guide I've read on them suggest an 8.1 to 8.3 range. If it's not that big of a deal then I won't go crazy trying to raise the pH, but if it beneficial to the fish's health then I try to do everything I can do to help with that
 
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Paston1

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Recirculate the scrubber.
Air stone bubbler at night.
Increase tank turn over rate.
check your alk in the tank.
Reverse sump lighting to display.

On the skimmer check your tuning to make sure a lot of those bubbles aren’t escaping on the opposite side of the skimmer. I have the next size up nyos.

on the co2 scrubber check the lines. I made this mistake and had it in reverse for where air came in vs left at.
 
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Randy Holmes-Farley

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I've not heard of that, but I assume you take a pH reading of the water before and after aeration to see if it raises the pH? If it's not the CO2, then I'm not sure what else it could be.

It can only be CO2 or low alkalinity, but home air is not the only source of CO2. The tank itself may not be aerated enough.

Try the aeration test:


The Aeration Test

Some of the possible causes of low pH listed above require an effort to diagnose. Problems 3 and 4 are quite common, and here is a way to distinguish them. Remove a cup of tank water and measure its pH. Then aerate it for an hour with an airstone using outside air. Its pH should rise if it is unusually low for the measured alkalinity (Figure 2). Then repeat the same experiment on a new cup of water using inside air. If its pH also rises, then the aquarium’s pH will rise simply with more aeration because it is only the aquarium that contains excess carbon dioxide. If the pH does not rise in the cup (or rises very little) when aerating with indoor air, then that air likely contains excess CO2, and more aeration with that same air will not solve the low pH problem (although aeration with fresher air should). Be careful implementing this test if the outside aeration test results in a large temperature change (more than 5°C or 10°F), because such changes alone impact pH measurements.
 
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Treldeham

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It can only be CO2 or low alkalinity, but home air is not the only source of CO2. The tank itself may not be aerated enough.

Try the aeration test:


The Aeration Test

Some of the possible causes of low pH listed above require an effort to diagnose. Problems 3 and 4 are quite common, and here is a way to distinguish them. Remove a cup of tank water and measure its pH. Then aerate it for an hour with an airstone using outside air. Its pH should rise if it is unusually low for the measured alkalinity (Figure 2). Then repeat the same experiment on a new cup of water using inside air. If its pH also rises, then the aquarium’s pH will rise simply with more aeration because it is only the aquarium that contains excess carbon dioxide. If the pH does not rise in the cup (or rises very little) when aerating with indoor air, then that air likely contains excess CO2, and more aeration with that same air will not solve the low pH problem (although aeration with fresher air should). Be careful implementing this test if the outside aeration test results in a large temperature change (more than 5°C or 10°F), because such changes alone impact pH measurements.
Thank you. I aerated some tank water outside and it brought the pH up to around 8.2, so it seems like the skimmer isn't aerating enough. Do you have any suggestions on what more I could do? I might pump some air from outside to an airstone in my tank, but the air tubing will be about 50' so I'm not sure how well it will work, especially since the pump will have to be outside as well.
 
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Paston1

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Thank you. I aerated some tank water outside and it brought the pH up to around 8.2, so it seems like the skimmer isn't aerating enough. Do you have any suggestions on what more I could do? I might pump some air from outside to an airstone in my tank, but the air tubing will be about 50' so I'm not sure how well it will work, especially since the pump will have to be outside as well.
I use air stones at night for my whole tank. Consider how when you prazi or chemiclean and they say leave skimmer on but cup off. Your tank survives that.

I would also argue the scrimped might be doing its job but the return is failing you on turn over rate. If that’s not the issue then your in tank turnover is low. This I just find out due to adding additional powerheads on my tank. 6 now and well increasing the tank display flow the new water is better spread out and old water moved back out.
 
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Randy Holmes-Farley

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Thank you. I aerated some tank water outside and it brought the pH up to around 8.2, so it seems like the skimmer isn't aerating enough. Do you have any suggestions on what more I could do? I might pump some air from outside to an airstone in my tank, but the air tubing will be about 50' so I'm not sure how well it will work, especially since the pump will have to be outside as well.

It may just be that your aeration with high CO2 indoor air (tank top, etc.) overpowers the skimmer.

Fresh air may be the best option if supplementing alk with hydroxide and using outside air/scrubber air in a skimmer isn't sufficient.
 
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ReefStable

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I've tried the CO2 absorbing media with little success. It helps, but only a little it seems.

I ran the air input outside and now my tank is always sitting around 8.2 pH (but more importantly, it's stable).

So I would encourage running the line outside and seeing if it helps.

What are you using to test? Most test kits will vary a lot because pH is always fluctuating. It's best to use a probe like that on the Apex to graph the pH and see the effects over time.

 
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Treldeham

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I've tried the CO2 absorbing media with little success. It helps, but only a little it seems.

I ran the air input outside and now my tank is always sitting around 8.2 pH (but more importantly, it's stable).

So I would encourage running the line outside and seeing if it helps.

What are you using to test? Most test kits will vary a lot because pH is always fluctuating. It's best to use a probe like that on the Apex to graph the pH and see the effects over time.

Thanks! I'm also going to try hooking my skimmer's input to the outside. I'm using Hanna Instrument's pH reader, so it's pretty accurate. I don't have an Apex, but I do take readings throughout the day to see how it fluctuates (unfortunately can't do any readings at night).
 
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