PH Can’t raise it

[chuckfu5]

Hello,

I’ve got a 135 with a 40 gallon sump that I’m having issues with PH. My levels stay anywhere from 7.78 to the highest is 8.0 but is usually around 7.9.

I added some two little fishes c02 absorbing media to the skimmer air intake yesterday and have yet to notice an improvement.

Anything I should try or do? I’d like to get it up around 8.0 to 8.2 for coral growth.

Thanks

 

[pluikens]

I am pulling air from outside through a CO2 scrubber and my pH hasn't been above 8 longer than my Apex goes back (one week). Do you run a refugium a grow macro algae when your display lights are off? You're probably about to get some suggestions to dose kalkwasser in your ATO. I've never used Kalk and as long as my corals look healthy and I notice some growth, I've resolved to be OK with 8 as my goal rather than 8.3.

 

[chuckfu5]

I do run a refugium opposite of my tank lights.

It actually seems like my PH has gotten worse since I added the c02scrubber. I tested the big 3 yesterday and here are my results.

Alk was 7.7 adjusted calcium reactor and will retest today. I’m trying to stay around 8.4 so that’s encouraging that it is going down.

Calcium 430

Magnesium 1300

Any ideas?

 

[pluikens]

I'd want someone that runs a calcium reactor to chime in but your calc reactor is adding alkalinity, mostly bicarbonate, which will lower your tank pH. If you just adjusted your calc reactor to keep your alk level up, then I'd expect the tank to have a lower pH until the increased CO2 is degassed.

 

[chuckfu5]

It’s not the bicarbonate that lowers the ph it’s the c02 that escapes the reactor and enters the water.

 

[chuckfu5]

I'd want someone that runs a calcium reactor to chime in but your calc reactor is adding alkalinity, mostly bicarbonate, which will lower your tank pH. If you just adjusted your calc reactor to keep your alk level up, then I'd expect the tank to have a lower pH until the increased CO2 is degassed.

I just reread this and yes that is a possibility why it’s low now because of the excess c02 from the change in the reactor.

 

[chipmunkofdoom2]

I'd want someone that runs a calcium reactor to chime in but your calc reactor is adding alkalinity, mostly bicarbonate, which will lower your tank pH. If you just adjusted your calc reactor to keep your alk level up, then I'd expect the tank to have a lower pH until the increased CO2 is degassed.

Dosing bicarbonate as opposed to carbonate will slightly lower your tank's pH, but the effect is very small. For every 1.4 dKh increase in carbonate alkalinity, the pH of the tank will only lower by 0.04 units. This requires a pretty well-calibrated pH meter to even detect.

The overall low pH of the effluent, due to the high CO2 content of the water, is likely responsible for more of the pH decrease than the effluent's carbonate/bicarbonate equilibrium. EDIT: That is, if the calcium reactor is responsible for the low pH in the first place.

 

[pluikens]

Dosing bicarbonate as opposed to carbonate will slightly lower your tank's pH, but the effect is very small. For every 1.4 dKh increase in carbonate alkalinity, the pH of the tank will only lower by 0.04 units. This requires a pretty well-calibrated pH meter to even detect.

The overall low pH of the effluent, due to the high CO2 content of the water, is likely responsible for more of the pH decrease than the effluent's carbonate/bicarbonate equilibrium. EDIT: That is, if the calcium reactor is responsible for the low pH in the first place.

Oh I agree it's too soon to declare the calc reactor has decreased tank pH when it's been maybe 24 hours and pH is only about .05 less than 24 hours prior based on the graph.

 

[lapin]

You can run a successful tank at that pH. Don't chase it too far. Make sure your probe is calibrated. You can try to drip the effluent into the first chamber of your sump so it goes thru some over under partitions and your skimmer to de gas it. Might help if its a CO2 issue. I would try to get your Alk up. Randy's baked baking soda works for that. It will take a while to get your reactor tuned. I had low pH until I started up my cal reactor. I raised my alk and the reactor made it stable. As a bonus my pH is now 8.02 night to 8.13 day. From mid 7's

From http://reefkeeping.com/issues/2002-05/sh/feature/

Low Tank pH

After adding a calcium reactor, many aquarists complain that the pH of the tank is lower than it was previously. Aquarists often think that excess CO2 in the effluent that has not had time to react with and dissolve the media is the reason for the reduced pH. However, remember that the calcium reactor is adding alkalinity, mainly in the form of bicarbonate, (which itself will depress the tank pH) until excess CO2 is degassed into the atmosphere. Some of the bicarbonate is then converted into carbonate. This is very similar to the effect observed when adding sodium bicarbonate to your tank as a buffer.

In order to rid the tank of any excess CO2 and maintain a good pH, it is essential to have good circulation at the air/water interface.

The pH can also be boosted by using limewater as top-off water. Limewater (also known as kalkwasser) works by using the CO2 in the tank water and the hydroxide ions from the limewater to increase the alkalinity. In turn, removal of the excess CO2 leads to an increase of the tank pH.

Another popular technique to remove excess CO2 is to degas the effluent, either by running it through an additional container of calcium carbonate chippings or by dripping the effluent into a small container housing an air stone. Results from these methods vary, with some aquarists reporting significant increases in alkalinity or pH and others seeing little observable difference (probably due to different calcium reactor designs and their effectiveness). With both of these methods you must be careful. As the pH is driven back up towards natural seawater levels, some of the bicarbonate is converted into carbonate. Once the water becomes supersaturated with carbonate, it will be more inclined to precipitate onto calcium carbonate surfaces, and some alkalinity will be lost.

 

[pdxmonkeyboy]

open your windows?

 

[kles]

Kalk will help keep ph up n stable . I use is even with calcium reactor just for that reason .

 

[Joe Grubbs]

@lapin & @kles some good points.

After 10+ years of running my CaRx, my pH stayed in the upper 7s with alk between 9.8 - 10.2.

I did find that running the effluent of the CaRx through a second chamber of media and discharging the effluent in front of the macroalgae in the sump was effective in raising pH 0.3 to 0.5.

When discharging the CaRx effluent into the skimmer helped pH I experienced a lot of precipitates build up in the Skimmer.

 

[Randy Holmes-Farley Verified Community Expert]

Oh I agree it's too soon to declare the calc reactor has decreased tank pH when it's been maybe 24 hours and pH is only about .05 less than 24 hours prior based on the graph.

A CaCO3/CO2 reactor will generally lower tank pH. It's not really a question of if, but how much.

 

[Randy Holmes-Farley Verified Community Expert]

It’s not the bicarbonate that lowers the ph it’s the c02 that escapes the reactor and enters the water.

It's both.