Help with Calcium Reactor and dropping Alk

[VJV]

Hi, I setup my first calcium reactor 3 weeks ago as I got tired of mixing 4 gallons of three part every other week in my 200 gallon system. I have a couple of very large and fast growing SPS in this tank.

I am using a pH probe with my Profilux 4 to maintain a pH of 6.4 to 6.5 inside the reactor. I have a constant stream coming out of the effluent and some 2 to 3 bubbles per second of CO2.

I have also started to add Kalk to my ATO to counter the plunge in pH that occurred in my tank. Oh, and the media I am using is Caribsea ARM coarse.

Even with the aid of the Kalk, my Alk levels are dropping and I am having to add about 0,5dKH per day to keep it stable at around 7,7dKH.

Is this normal? With such a high effluent rate, low pH inside the reactor and high bubble count as well as Kalk I should be able to easily keep up with the demands right...?

 

[Lostreefin]

Hi, I setup my first calcium reactor 3 weeks ago as I got tired of mixing 4 gallons of three part every other week in my 200 gallon system. I have a couple of very large and fast growing SPS in this tank.

I am using a pH probe with my Profilux 4 to maintain a pH of 6.4 to 6.5 inside the reactor. I have a constant stream coming out of the effluent and some 2 to 3 bubbles per second of CO2.

I have also started to add Kalk to my ATO to counter the plunge in pH that occurred in my tank. Oh, and the media I am using is Caribsea ARM coarse.

Even with the aid of the Kalk, my Alk levels are dropping and I am having to add about 0,5dKH per day to keep it stable at around 7,7dKH.

Is this normal? With such a high effluent rate, low pH inside the reactor and high bubble count as well as Kalk I should be able to easily keep up with the demands right...?

Have you calibrated your pH probe? I only have 120g, but I run my ph at 7.2-7.3 in my reactor with a steady stream and get plenty of Alk that way, maintaining 9.5dKh. I am using Reborn media, your CO2 amount seems about right. My tank is relatively new with pretty low demand though. I know another guy with 300+g and he doesn't run his below 7pH in the reactor, that pH seems really low to not be giving you enough alkalinity.

 

[VJV]

Thanks. Yes I did calibrate the probe and it is a brand new one. From what I understand Reborn is a much softer media that dissolves ata higher pH. ARM coarse from what I read needs 6.5 (and I have seen as low as 6,3 in the forums).

I have some very large colonies and would run through 1,2 liters per day so I know I have a high consumption level. Still, with the current setup plus Kalk I was expecting this to be enough...

I need to test the Alk of my effluent and see how it is coming out...

 

[Lostreefin]

I know people that have huge consuption with tons of established colonies that keep up at above 7pH in the reactor. I would be surprised if you are exceeding the capability of the reactor. Are you melting through media crazy fast? Maybe try Reborn?

 

[VJV]

I know people that have huge consuption with tons of established colonies that keep up at above 7pH in the reactor. I would be surprised if you are exceeding the capability of the reactor. Are you melting through media crazy fast? Maybe try Reborn?

Unfortunately there is no reborn where I live. In any event, the melting point of the media varies from one type to the other so for people using reborn 7.0 should be fine, for Caribsea ARM you need to go lower to achieve the same.

The advantage I see in reborn is that by using a higher pH you have a smaller impact on your tanks pH, which is important.

 

[VJV]

Any other ideas? I have been told to lower the effluent rate to increase the Alk content but given it is being controlled by a pH probe set to 6,5 I do not see how a lower effluent rate would increase the Alk content, as the solenoid would stop the pH in the reactor from going any lower...?

 

[Lostreefin]

I think checking your effluent was a great idea, to make sure you are getting enough alk from your media, and that your pH is really that low. I agree that a more concentrated effluent will not make a difference compared to more lower concentration. Do you have a second chamber?

 

[VJV]

I think checking your effluent was a great idea, to make sure you are getting enough alk from your media, and that your pH is really that low. I agree that a more concentrated effluent will not make a difference compared to more lower concentration. Do you have a second chamber?

Thanks. I do not have a second chamber no. I will likely restart my refugium to try and boost the tank’s pH (my sump is a custom made one with a refugium section so it should not be too difficult).

 

[VJV]

I have been going through a number of threads and it seems CaribSea ARM corse media needs a pH of 6,3 or lower to provide any meaningful Alk. So I will try to lower down to 6,3 and see if it improves.

 

[Lostreefin]

Good idea! I think you will get there, melt that stuff down, but watch the tank pH for sure.

 

[jda]

Any of the natural carib sea stuff melts just the same as reborn for me. Only the man-made stuff needs to go lower. What you are probably seeing is differences in people pH probes - remember that these are hobby grade tools so do not rely on them too much.

I would stop using the pH probe and just tune it by hand. You should be getting an output dKh in the mid to high 20s - if you use Salifert you can just keep taking the last syringe as many times as necessary until the color changes... and then add them all up... this might take 3 syringes. Make sure that you are at least over 20 or else your reactor is not melting enough stuff. Then, turn the effluent and bubbles up in sequence until your daily drop stops - the dKH should be over 20 when your turn it up.

If I had to guess, your effluent stream is too fast. I have a tank with a huge demand and I have a broken stream of effluent - not constant. We totally could be mixing terms, though, so best to measure in mls once you are past counting drops.

The CaRx alone should be able to keep up. I have to melt 50 pounds of reborn or ARM (I just buy whatever is on sale) every six months and the reactors are more than capable of this.

Remember that a slower effluent and fewer bubbles can accomplish the same thing as faster and more. Get a reading on the effluent dKh and let us know what it is.