effect on ph from refugium

[ReefBeta]

Last night I was doing some rescaping. I turned off flows, but left lights of refugium on, for several hours.

The refugium was just a small 4" x 8" area, started couple weeks ago, with mostly ulva. The light is a 24w agriculture bulb from ebay. The pH probe happens to between the same baffles of the refugium, so I guess most change on pH stayed in that section.

And here is how the pH graph looks like during that period.

It manage to drive the pH faster and higher than when the main lights were on, even it's just in small area, although it's too small to make a meaningful dent to the whole system. I find it very interesting and just want to share.

 

[joekool]

Well its like trees in a sense. The refugium is using up Co2 while light is on and giving out O2. reducing the Co2 will increase PH. This is why most people run them on a reverse light cycle or they run the 24 hours.

If you need more PH in your tank you could plumb a fresh air line from out side to your intake air of the skimmer or increase your fug size as long as you can feed it to keep it alive.

 

[ReefBeta]

I knew how algae grow affect pH, just didn't find too much info on actually using it for the purpose of raising pH. Most of discussions on refugium or algae reactor are about nutrition export, but I honestly don't care too much about that at this point, as I'm already running on near 0 nitrate and phosphate before implementing the refugium.

I'm more curious on it serve as CO2 scrubber. This example serve me as a proof of concept, as well as give me an idea how much does it take to bring meaningful impact.

It also lead me to curious how would ATS do in that regard. As my understand, ATS's advantage is allow algae to use CO2 from the air. So it might have a lot less impact on pH of the water, and it would be less useful for the purpose of CO2 scrubbing.

 

[Roy 9121]

Well its like trees in a sense. The refugium is using up Co2 while light is on and giving out O2. reducing the Co2 will increase PH. This is why most people run them on a reverse light cycle or they run the 24 hours.

If you need more PH in your tank you could plumb a fresh air line from out side to your intake air of the skimmer or increase your fug size as long as you can feed it to keep it alive.

You need to feed a refugium? What do you feed it?

 

[Randy Holmes-Farley Verified Community Expert]

I knew how algae grow affect pH, just didn't find too much info on actually using it for the purpose of raising pH. Most of discussions on refugium or algae reactor are about nutrition export, but I honestly don't care too much about that at this point, as I'm already running on near 0 nitrate and phosphate before implementing the refugium.

I'm more curious on it serve as CO2 scrubber. This example serve me as a proof of concept, as well as give me an idea how much does it take to bring meaningful impact.

It also lead me to curious how would ATS do in that regard. As my understand, ATS's advantage is allow algae to use CO2 from the air. So it might have a lot less impact on pH of the water, and it would be less useful for the purpose of CO2 scrubbing.

It works, and I detail it in my pH articles, but very often it is not adequate to overcome high CO2 room air.

Yes to the last point on ATS. They allow more aeration so can be less useful, per unit of photosynthesis, to raise pH if the room air is the primary problem.

 

[ReefBeta]

I also learnt that too high of PAR is not good for the refugium, at least not from the start. Initially I put the light too low, and it's blasting like 1300+ PAR on the ulva and its edge was turning white. Then I raise the light and it now do about 800 PAR and now they are doing well.

It's useful info for me as I want to build an algae reactor later. The zero distance from LED strip may easily bring over 1000 PAR, so I need to keep that in mind and don't wrap too much light on the reactor.