My Experience Raising pH

[Want2BS8ed]

@Want2BS8ed, many thanks for the picture. Did you notice a slight reduction in pH when you connected the air to the skimmer? I am just wondering if air only being pulled from outside and then through the scrubber has a lower C02 level than air being pulled through the scrubber and from the skimmer? I am just running another test to see how long my media lasts directly through the scrubber but will then give your solution a go.

No, no noticeable difference and I ran the bypass intake dry for quite some time before the replumb.

The current location is really nothing more than a matter of convenience. As long as I was drilling and tapping the skimmer cover, it was easy to do two and the installation wound up a bit tidier. Previously the valve was just flopping around.

The valve was purchased from McMaster-Carr (there is likely a similar outfit in the U.K.) and comes with push connect fittings - 3/8" in my case, but 1/4" and 1/2" are available. Plumbing couldn't be easier.

Neptune also has a 1/4" valve, but it is fairly restrictive and I wouldn't recommend it for this use.

If you have one of the newer 2016 Apex Energy Bar 832's or a Neptune Fluid Monitoring Module (FMM), etc. you can also purchase the valve in a 24-volt version and free up one of the main outlets on your Energy Bar.

I just purchased one of Neptune's 24-volt extension cords and nipped one end off and wired it to the valve. Again, couldn't be much easier.

And just for reference, the bypass is set to come on at 8.3 and go off at 8.2. If I were a little less greedy and lowered it to 8.2/8.1 the media would likely last even longer.

M

 

[Clownfishy]

UPDATE: C02 Scrubber Modification
As expected, after 2 weeks of adding new media to the C02 scrubber, the Soda Lime granules started to degrade dropping my pH below 8.20 at night.

At 2.5 weeks, I added a modification to the scrubber as recommended by @Want2BS8ed. I re-plumbed the air intake so it is taking some air from outside and some from the skimmer cup. I will now replace the Soda Lime granules to see if this extends the life beyond 3 weeks which is expected.

 

[Want2BS8ed]

UPDATE: C02 Scrubber Modification
At 2.5 weeks, I added a modification to the scrubber as recommended by @Want2BS8ed. I re-plumbed the air intake so it is taking some air from outside and some from the skimmer cup. I will now replace the Soda Lime granules to see if this extends the life beyond 3 weeks which is expected.

I am not certain splitting the intake will be overly effective. Air will follow the paths of least resistance and if your fresh air intake is less restrictive, the intake to your skimmer will favor that line.

My recommendation would be to pull it all from the scrubber and use outside air on the bypass if you had too.

Keep us informed though.

M

 

[Clownfishy]

In my last update, I connected my C02 scrubber to the skimmer as well as drawing in air from the outside. I did this just before I needed to change the media as I was at the 2.5 week point where I started to see a drop in pH. However, by just connecting the scrubber to the skimmer, I managed to get another 1.5 weeks of life from the granules as @Want2BS8ed and others have said, so pulling air from the skimmer definitely extends the life of the Soda Lime granules.
Last night I saw a big drop in pH so figured I had now exhausted the granules after 4 weeks of use, so I swapped them out and removed the connection to the outside air so the Co2 scrubber is only pulling air from the skimmer. I am going to now run it like this to see how long the granules last.

 

[Randy Holmes-Farley]

In my last update, I connected my C02 scrubber to the skimmer as well as drawing in air from the outside. I did this just before I needed to change the media as I was at the 2.5 week point where I started to see a drop in pH. However, by just connecting the scrubber to the skimmer, I managed to get another 1.5 weeks of life from the granules as @Want2BS8ed and others have said, so pulling air from the skimmer definitely extends the life of the Soda Lime granules.
Last night I saw a big drop in pH so figured I had now exhausted the granules after 4 weeks of use, so I swapped them out and removed the connection to the outside air so the Co2 scrubber is only pulling air from the skimmer. I am going to now run it like this to see how long the granules last.

Do I understand correctly that the skimmer air is being recycled? IS all of the skimmer air recycled that way? I can see how that can help pH, but my concern is you are no longer providing O2.

 

[TNT32D]

How much soda lime do you go through every 3 weeks?

 

[Clownfishy]

@Randy Holmes-Farley , it's funny you bring this up. After about 2 hours installing this, I was wonder the same thing and if the other holes in the skimmer lid would pull in enough new air so I have put it back to how I had it before, pulling air from the outside and the skimmer.
Do you think it would reduce the O2 pulling just the recycled air from the skimmer cup?

 

[Clownfishy]

@TNT32D I am not sure how much in weight but scrubber is one of these -
https://www.finest-filters.co.uk/refillable-inline-filter-housing-for-di-resin-carbon/

So far I have managed to fill one of these with Soda Lime granules and it has lasted 4 weeks. I think I should now be able to extend this now that I am taking air from both the skimmer and outside.

 

[Clownfishy]

If anyone had any doubt over the use of Soda Lime granules to raise pH, the below chart shows the pH rise after replacing the old granules with new in the C02 scrubber. Note the rise continues during the night and that it hit 8.36 with the lights just turning on. I have noted the opposite problem in that you have to keep checking the pH doesn't rise too high after replacing the granules. I also now need to adjust my alkalinity and Calcium as I see a greater uptake.
From previous experience, my pH will stay above 8.30 then slowly dropping to 8.20. As you would have seen from a previous post, the first time I see a big drop below 8.10 during the night, I change the granules as that is the point the Soda Lime granules do seem to be stripping out much C02. I will post an update to let everyone know how long they last now the air is being taking from the outside as well as the skimmer but I am expecting longer than 4 weeks.

 

[Want2BS8ed]

Do I understand correctly that the skimmer air is being recycled? IS all of the skimmer air recycled that way? I can see how that can help pH, but my concern is you are no longer providing O2.

No, it is not an entirely closed system and there will always be some bypass. Moist air is what is needed to prolong the life of the media.

I wish O2 meters were not so expensive, because it would be interesting to test, but I suspect there would be little change in O2 saturation.

That brings up an interesting question though Randy you may be able to answer. I have been blindly using soda lime knowing the end result, but how does it really work? Is it exchanging ions or absorbing ions? Basically CO2 laden air goes in, so what comes out and why does moist air increase longevity?

Apologies in advance for answering a question/comment with another question, however I am curious now. Thanks!

 

[Randy Holmes-Farley]

@Randy Holmes-Farley , it's funny you bring this up. After about 2 hours installing this, I was wonder the same thing and if the other holes in the skimmer lid would pull in enough new air so I have put it back to how I had it before, pulling air from the outside and the skimmer.
Do you think it would reduce the O2 pulling just the recycled air from the skimmer cup?

I think at night, aeration with O2 is a substantial benefit in most reefs, and complete recycling of the skimmer air eliminates that benefit. I can't really say how much holes help since I'm not sure much will come in or out them.

 

[Randy Holmes-Farley]

No, it is not an entirely closed system and there will always be some bypass. Moist air is what is needed to prolong the life of the media.

I wish O2 meters were not so expensive, because it would be interesting to test, but I suspect there would be little change in O2 saturation.

That brings up an interesting question though Randy you may be able to answer. I have been blindly using soda lime knowing the end result, but how does it really work? Is it exchanging ions or absorbing ions? Basically CO2 laden air goes in, so what comes out and why does moist air increase longevity?

Apologies in advance for answering a question/comment with another question, however I am curious now. Thanks!

Yes, but you can easily make moist fresh air simply by passing the fresh air over some water before getting to the media.

Soda lime is a mixture of calcium oxide and sodium hydroxide. Very high pH and lots of calcium. The hydroxide in the media converts into carbonate and it stays there as calcium carbonate or sodium carbonate, just like when adding limewater to an aquarium. There's no exchange where something leaves.

 

[Clownfishy]

Its my understanding that pulling air from the skimmer cup has two main benefits -

1. Pulls moist air through the Soda Lime extending their life (not sure of the science behind this?)
2. As the air has already been through the scrubber, a lot the C02 has already been removed so the Soda Lime does not have to extract as much C02 from the air the second time it passes through, again extending its life.

I guess we really need an O2 and a C02 meter to really help understand what it going on. Does anyone know if this type of testing has been performed before? The dissolved oxygen probe for the Apex is insanely expensive so not something I will be able to do anytime soon!

By the way, my pH reached 8.38 just before the lights went off for the evening so I reached an average of 8.34 in the last 24 hours and an average of 8.23 over a 2 week period.

 

[Randy Holmes-Farley]

Its my understanding that pulling air from the skimmer cup has two main benefits -

1. Pulls moist air through the Soda Lime extending their life (not sure of the science behind this?)
2. As the air has already been through the scrubber, a lot the C02 has already been removed so the Soda Lime does not have to extract as much C02 from the air the second time it passes through, again extending its life.

I guess we really need an O2 and a C02 meter to really help understand what it going on. Does anyone know if this type of testing has been performed before? The dissolved oxygen probe for the Apex is insanely expensive so not something I will be able to do anytime soon!

By the way, my pH reached 8.38 just before the lights went off for the evening so I reached an average of 8.34 in the last 24 hours and an average of 8.23 over a 2 week period.

I do not know if question 2 is correct or not. It comes down to whether the air exiting the skimmer has more or less CO2 than the room air. The answer may depend on the time of day in the aquarium. More likely to be true during the light cycle than at night. But it may be true 24/7, or never true, depending on the aquarium and the room air.

 

[Want2BS8ed]

Yes, but you can easily make moist fresh air simply by passing the fresh air over some water before getting to the media.

Thanks Randy.

The surface area in a skimmer for gas exchange is massive - as you correctly point out in its importance for O2 exchange. Is it not a two way street though? Shouldn't we anticipate the same efficiency in saturating/super-saturating expelled air from the skimmer with moisture/humidity? In effect moister?

Soda lime is a mixture of calcium oxide and sodium hydroxide. Very high pH and lots of calcium. The hydroxide in the media converts into carbonate and it stays there as calcium carbonate or sodium carbonate, just like when adding limewater to an aquarium. There's no exchange where something leaves.

So absorption, correct? Something may not leave the media, but CO2 is stripped from the incoming air and bound either partially or entirely as calcium carbonate or sodium carbonate?

What about the second part? Why does moisture laden air extend the life of the media?

 

[Night Reefer]

Sorry for the late reply #Clownfishy.

Nothing original, BRS explained it well in their video including the valve part # from McMaster-Carr.

Again, I have been extremely pleased with both the positive impact on pH as well as the longevity of the media since making the change.

M

Have some question before I implement this.

So the Venturi gets air from the scrubber or the skimmer depending on the valve?
Is the valve normally open or normally closed?
Is the white plate the top of the skimmer waste jar?

I currently have mine setup like the brs video and I am getting a wide flucation as it is pulling too much air from the scrubber and not enough of regular air when my valve is activated.

 

[Want2BS8ed]

Have some question before I implement this.

So the Venturi gets air from the scrubber or the skimmer depending on the valve?

Yes, it is either 100% through the scrubber or 100% through the bypass. Both air inlets in my installation pull from the skimmer cup.

Is the valve normally open or normally closed?

The valve is normally closed and opens for the bypass - that way the valve's coil is only energized when bypassing the scrubber. Roughly in a 24 hour period 2/3rds to maybe 3/4 of the time air is being pulled through the scrubber, so that seemed the more efficient and less stressful route.

Is the white plate the top of the skimmer waste jar?

No, I have an Avast Swabbie neck cleaner on the skimmer. The plate is the cover for the skimmer cup.

I don't think it makes a bit of difference if you are pulling air from the skimmer cup or waste jar. Air should be equally humid.

Placing the valve above the skimmer seemed the logical thing to do in case there is a failure. My skimmer is also mounted on the wall at about eye level. The scrubber is mounted to a joist in the ceiling. Going to the skimmer cup allowed a shorter run of tubing.

I currently have mine setup like the brs video and I am getting a wide flucation as it is pulling too much air from the scrubber and not enough of regular air when my valve is activated.

I would have anticipated the opposite assuming restrictions from the media vs. straight tubing. Couple of quick questions:

1) what valve are you using? They are not all created equal. I know the Neptune Systems valve is very restrictive for instance.

2) are the scrubber and bypass pulling air from the same location? I could see in a closed system where scrubber air from either the skimmer cup or waste collector might be slightly pressurized where a free air intake might not causing what you describe.

A picture would be helpful.

 

[Want2BS8ed]

Here is a wider shot of the skimmer installation. Rather ghetto, but effective. It sits on 3 heavy duty shelf brackets from Lowe's lag bolted into the concrete wall. The empty lag bolts to the left of the skimmer were the old location for the BRS jumbo canisters before I moved them up to the ceiling.

There is a small table attached to the wall below the skimmer for test kits, etc.

The 4 1-1/2" flex PVC lines in the background go through the floor for a Beananimal overflow and return. The 4" PVC pipe between the two canisters is the exhaust for a closed gas hot water heater.

125 gallon sump is to the right and sits 24" off the floor, the skimmer's bottom is about 12" above the sump's rim. Waste is collected in a 2-1/2 gallon paint bucket that sits on the floor with an Avast Davey Jone's Locker with sensor on top.

 

[Night Reefer]

Using the Neptune valve but converted everything to 1/4 tubing and air is from the same location. Funny thing is values peek at roughly midnight. I am going from 7.8 to 8.0. I found that when the valve kicked on I was still bring in scrubber air which raised ph even higher. I was thinking of cutting the air from the scrubber instead of the room air. What are your thoughts?

 

[Want2BS8ed]

Using the Neptune valve but converted everything to 1/4 tubing and air is from the same location. Funny thing is values peek at roughly midnight. I am going from 7.8 to 8.0. I found that when the valve kicked on I was still bring in scrubber air which raised ph even higher. I was thinking of cutting the air from the scrubber instead of the room air. What are your thoughts?

Honestly, I would get a solenoid valve that did not have any restrictions like here: https://www.mcmaster.com/#solenoid-valves/=1dqqt6c

The Neptune valve is just to restrictive and if you reverse it, your problem will only flip.

Remove the Neptune valve, actuate it and try blowing through it. You can literally feel the back pressure. I tried one as a shut-off for an Ozone line, and even with an air pump (the valve was between the pump and O3 generator), it stopped working - it couldn't pass enough air when open and ORP plummeted.

The McMaster valve is certainly more expensive up front, but it is a direct pass through without restriction. The savings comes in not having to replace media as often.

I purchased a 3/8" 24v valve, nipped the end off of a Neptune Systems 24v extension cord and wired it to the valve. That way you can still plug it into an APEX auxiliary outlet and not have to give up a 120v outlet on your Energy Bar. The lower voltage should also be safer and generate less heat in the valve's solenoid.