CaRx issues

[menglish]

So I have been testing and testing for the past few days.  Here are the latest numbers.

After lowering the pH in the CaRx chamber from 6.3 to 6.2, the Alk of the effluent has settled to 19 dKH from a high of 25.   

19 dkh is still lower than i was expecting, but i will have to work with that.

I had the flow rate of the effluent at 45 mls/min, but i noticed it was slowing down. I think it was clogging.

I have now tried to increase it to a faster drip or about 60mls/min.  The alk in the tank has ranged from 8.6 to 8.9.  I was shooting for 9dkh.

i will continue to test it and see how stable it stays.  Also, I am still dossing Kalk and keeping the ph in the stirr above 12.  The ph in the tank is now  between 7.9-8.1.  I would like it higher, but i am ok with that.

Any thoughts?

[Origami]

Sorry, Milton, I was out of pocket for a few days.

 

The pH in your tank is reasonable for a system on a calcium reactor. But, with also dosing kalkwasser in your top off water, I would expect it to be a little higher. 

 

Slowing effluent is likely clogging. If you've got a small centrifugal feed pump and the flow is relatively low, you can definitely get clogging. That's why I never really liked the "drip" approach to using a calcium reactor - the valves used to regulate the drip rate tend to clog with calcium carbonate. You may also have some sort of obstruction in the lines somewhere. It's worth pulling the lines off at various places to see if the flow is relativey constant. If it is, then the resistance between those points is low. If the flow decreases at any one of the stages, it indicates resistance in that stage.

 

Now, a quick question based on an earlier post: You said that when you turned off the feed pump for a few hours that the reactor pH increased from 6.4 to 6.63. That seems strange to me because your controller is set to deliver CO2 to the reactor above pH of 6.40. If that's the case, then why would it have even reached 6.63? 

 

By the way, what method are you using to measure this high alk range?

 

 

[wangspeed]

Are you running the CO2 solenoid off a controller with a log? Like an Apex? One thing that helped me determine whether or not things were working well is turning on logging for the solenoid on/off times, and looking for trends, like if the times get longer or shorter (indicating a problem). Maybe I missed it, but have you also tried checking your ph probe calibration? Just drop it in your tank and see what it reads.

 

Which Geo reactor do you have? Is there a bubble near the top? The older style ones with the pipe out the top need an additional port drilled to pull from that, which prevents a bubble from forming, which could also throw off your ph readings. Actually, dumb question, do you have the ph probe inserted deep enough into the chamber? Don't keep it too close to the top.

 

Other things I can think of. Do you hear the recirculation pump chopping up C02? That should only happen with new media, otherwise it's an indicator of a problem. Give the reactor a shake and make sure you hear the pump pull and chop up the bubbles. When I first setup my reactor, I ran my DC recirc pump a little too low, and it wasn't as consistent.

 

Despite your current troubles, a CaRx is a relatively simple device. With enough data points, we should be able to figure out what's going on with yours. If you have an Apex, a few extra logging options could help tremendously.

[menglish]

So some updates:

I did cleaned out the reactor and all the lines. Its a Geo 618 single chamber but I added Avast second chamber and I do have a ph probe in the mail reactor. No clog in the lines. I am using a small Eheim feed pump.

I did also refilled the reactor with new media, the ph set to 6.2 with a flow rate of 80mls/min and it ran like that all of last week ( i went skiing).

Came back today and did some test.

checked the effluent out of the reactor and the Alk is 30 (this is more in line of what i was expecting, perhaps because the reactor in now full)

I checked the Alk in the tank and it has jumped up to 12.5 dkh (Hannah checker)

I would like to keep the tank around 9dkh.

So now i have to dial it in again.

my plan:

1. turn off the CO2 and monitor the tank daily to allow the Alk in the tank to drop

2. I plan to reduce the flow rate to about 50 mls/min (this is a nice trickle and i think it will prevent clogging of the line)

3. increase the ph in the reactor from 6.2 to 6.3.

 

I reckon it will take a few days to dial in now that i am back home to play with it

Thoughts?

 

many thanks for your help.

 

Milton

[Origami]

Your basic approach is the way I'd deal with it: Patience. Shutting off the CO2 will cause a lag when you start back up. Another way is just to shut the flow down entirely and open back up when the alk has dropped some. It won't clog if it's not running.

[menglish]

Good idea,

will try that