CO2 advice

[martym]

Thats the issue I'm having. How else do you keep the Ph in the MD from dropping, if the Rx is running all the time?

[tang daddy]

technically if your rx comes on at 6.7 and goes off at 8 then either you have 2 ph monitors or you have set it wrong!!

the ph set for your monitor should kick off at ph 6-6.4 and on at 6.5-6.8, that is my understanding and as for your md it should hold at ph 7.8-8.3 with your lights coming on and off.

Mostly everyone on here will agree or have the same standards in mind, if you already have kalk dripping into your tank it should balance it out.

really it's up to you but if your reactor is not holding a 6-6.8ph then the calcium cannot melt therefore not meeting the demands of your tank.

My PH level runs at 7.8-7.9 w Cal reactor and dripping Kalk at night. I gave up worrying about it and let it sit there - no ill effects are observable after months in that range.

One thing that helped a little was running my effluent into my skimmer - seems to blow off more CO2 before it hits the main tank.

You may also want to make sure you are refreshing the air in your room - my ph goes up abit if the house is empty, and drops abit with more bodies. Opening a window near the tank helps stabilize those swings...

[martym]

Tang Daddy- That is basically how it is running. I do have 2 monitors. But for me the controller is in the main tank. The monitor is in the effluent just before it drips into the tank. So when the tank is above 8.01 the Rx turns on. The effluent then drops down to 6.7 and remains there until the ph in the tank drops below 8.0.
Yesterday for an example, I managed to leave the window in the room where the aquarium is open all day. The Rx came on at around 10am and was still running when I went to bed at 9:30pm. The Ph in the MD is at 7.9 this am (5:30am) So it is running, and maintaining the values that I'm after, for the most part. My Alk does dip down to 7DkH just before my bi-weekly WC. My concern is the Ph in the main display had dropped to below 7.8, which is a bad thing. I was hoping that I could keep it up a bit higher than that.

[StirCrazy]

for 5 years my PH was always 7.8, no problems. Add a Kalk reactor and if all it took was to open a window you need to ventalate that room.

On my system I ran the Ca Rx 24/7 and the kalk Rx on my top off water.

Steve

[untamed]

You are letting the pH of your display tank run your calcium reactor, which does not make any sense to me. It is not a tool designed to maintain pH....it is a tool designed to deliver Ca/Alk requirements. There is not a demand relationship between Ca/Alk and pH.

Here's how my reactor works... The pH probe is in the Ca Reactor chamber and the controller keeps that chamber at pH of 6.4 by adding Co2 when necessary. That is low enough to dissolve the media. The effluent from that reactor then goes through a 2nd stage where further reaction takes place. By the time the effluent comes out of the 2nd stage, the pH is up to 7.6. Optimally, it would be perfect if that effluent got back up to pH of 8.

I also have a pH probe in my display tank. It provides entertainment...but nothing else.

[martym]

My RX has only one chamber
here is how Randy Homles set his up. This is from is article on Reef Central.
"A more elaborate method is to connect the solenoid valve to a pH controller and place the pH probe into the calcium reactor. The valve then switches the CO2 on and off to maintain a target pH within the reactor. I use a similar method. The pH probe is placed in the tank, and switches off the CO2 flow to the calcium reactor only when the pH in the tank has dropped too low (e.g. pH 7.8 or lower).

This is how I run it, but I try not to let the PH get that low.

[Chin_Lee]

Marty
Randy's method and your method are very different. He is using the ph controller to control the pH inside a calcium reactor whereas you are using a ph controller to minimize the pH drop in your display tank.

I wouldn't be too concerned about the pH in the tank. 7.8 isn't really bad at all as this is quite normal for many reefers that do not does kalk. Use kalk to raise the pH in your display tank via a kalk reactor on an auto topoff.

I would use the pH controller to control the pH inside the reactor only. As more effluent exits your calcium reactor, it will buffer the system and prevent it from going any lower than 7.6.

[martym]

Ok, I have now changed what I was doing. The controller is in the effluent, has the rx come on if the Ph is above 6.8 and shuts off if it goes below 6.4.
Thanks everyone for your help.

[untamed]

Originally Posted by martym

My RX has only one chamber
here is how Randy Homles set his up. This is from is article on Reef Central.
"A more elaborate method is to connect the solenoid valve to a pH controller and place the pH probe into the calcium reactor. The valve then switches the CO2 on and off to maintain a target pH within the reactor. I use a similar method. The pH probe is placed in the tank, and switches off the CO2 flow to the calcium reactor only when the pH in the tank has dropped too low (e.g. pH 7.8 or lower).

This is how I run it, but I try not to let the PH get that low.

I get it. Randy is using low-pH as an emergency shut off for the reactor (at tank ph 7.8). By setting your shut off as high as 8.0, you probably shut down the reactor for most of time that your lights are off.