Ca Reactor & Tank pH Probe Calibration

cmhollis · 03/27/2006, 06:11 PM

I posted this in the Neptune forum but it isn't getting much traction there. Figured I would post it here:

Prior to starting up my calcium reactor, my tank pH would stay in the 8.2 - 8.4 range, and I was happy with that. Now my CR has been up and running for 2 days, and according to my system pH probe (located in the fuge) my system pH is 8.6 - 8.8. Thinking "That can't be right" (since a calcium reactor should be depressing system pH), I calibrated both pH probes last night using the individual pH standard packets. After calibration, system pH was reading 7.98 (I expected it to read in this ballpark due to CR operation). So last night I added a tsp of kalk powder to the sump and stirred it in till everything was dissolved. Checked the tank pH about an hour later on the ACIII and it read 8.26 or so.

I thought that everything was good, and went to bed. This morning I got up, and pH was again down around 8.00, so I added another spoon of kalk. Throughout the day after adding this pH stayed in the 8.2 - 8.3 range. I figured everything was good again.

So I just checked the display on the ACIII, and it read 8.65 or so, but it is coming down.

Has anyone encountered something similar when starting up a CR? I did check to make sure nothing was fouling the probe, and that it is completely submerged.

I am thinking about shutting down the CR for a couple of days and see what effect that has on system pH.

Thanks,

Mike

elosusa · 03/27/2006, 06:44 PM

This is a good article on your parameters. Read the part about ph:
http://www.reefkeeping.com/issues/2004-05/rhf/index.php

The CA reactor can't be the problem, assuming it is running properly. Perhaps, where the probe is located is the problem. If you have lights on the fuge it will affect your ph probe. Do you have the fuge on the same light cycle as your display lights? If you do, this would likely be one of the causes. The other maybe adding Kalk directly to the tank instead of slowly dosing it with top off water. If you have a slow flow going through the fuge, you would probably get more accurate readings with the ph in the sump with faster flow and no light. If you do have the lights on the same cycle as the display, I would reverse that and this will help stabilize the ph through the night. Read that article and you will see that it is quite common for people with CA reactors to run their systems in the 7.9-8.1 range. Hell, I know plenty of people who run it lower than that. Hope that helps.

03/27/2006, 06:11 PM	#1
cmhollis Registered Member Join Date: Jun 2005 Location: Ledyard, CT Posts: 1,226	Ca Reactor & Tank pH Probe Calibration I posted this in the Neptune forum but it isn't getting much traction there. Figured I would post it here: Prior to starting up my calcium reactor, my tank pH would stay in the 8.2 - 8.4 range, and I was happy with that. Now my CR has been up and running for 2 days, and according to my system pH probe (located in the fuge) my system pH is 8.6 - 8.8. Thinking "That can't be right" (since a calcium reactor should be depressing system pH), I calibrated both pH probes last night using the individual pH standard packets. After calibration, system pH was reading 7.98 (I expected it to read in this ballpark due to CR operation). So last night I added a tsp of kalk powder to the sump and stirred it in till everything was dissolved. Checked the tank pH about an hour later on the ACIII and it read 8.26 or so. I thought that everything was good, and went to bed. This morning I got up, and pH was again down around 8.00, so I added another spoon of kalk. Throughout the day after adding this pH stayed in the 8.2 - 8.3 range. I figured everything was good again. So I just checked the display on the ACIII, and it read 8.65 or so, but it is coming down. Has anyone encountered something similar when starting up a CR? I did check to make sure nothing was fouling the probe, and that it is completely submerged. I am thinking about shutting down the CR for a couple of days and see what effect that has on system pH. Thanks, Mike __________________ "These mist covered mountains, are a home now for me, but my home is the lowlands, and always will be." - Dire Straits Yes Amy, I am on the national marrow registry. Current Tank Info: 120g In-wall, MR3 skimmer w/ Blueline HD70, ACIII controller, CR3 calcium reactor, Sequence 5800 CLS via OM 4-way, Sequence 3200 return, 2 - 250W 10K MH, 1 - 150W 20K MH, 4 - 110W VHO Actinics

03/27/2006, 06:44 PM	#2
elosusa RC Sponsor Join Date: Jan 2006 Location: NorCal Posts: 272	This is a good article on your parameters. Read the part about ph: http://www.reefkeeping.com/issues/2004-05/rhf/index.php The CA reactor can't be the problem, assuming it is running properly. Perhaps, where the probe is located is the problem. If you have lights on the fuge it will affect your ph probe. Do you have the fuge on the same light cycle as your display lights? If you do, this would likely be one of the causes. The other maybe adding Kalk directly to the tank instead of slowly dosing it with top off water. If you have a slow flow going through the fuge, you would probably get more accurate readings with the ph in the sump with faster flow and no light. If you do have the lights on the same cycle as the display, I would reverse that and this will help stabilize the ph through the night. Read that article and you will see that it is quite common for people with CA reactors to run their systems in the 7.9-8.1 range. Hell, I know plenty of people who run it lower than that. Hope that helps. __________________ Jesse 877-373-0105(Toll Free) 925-600-8020(Office) info@elosusa.com www.facebook.com/elosusa Current Tank Info: yes