[Stappercrab]

175 gallon reef tank mix of SPS, LPS, and Soft Corals. Relatively heavy stock of fish (heavily skimmed)

I've got a pretty good understanding of pH and Alk (I think). In general, I test my Alk & calcium on a regular basis and buffer as needed. I'm in the process of trying to get a calcium reactor up & running, but have a difficult time getting the bubbles to remain consistent (different problem).

I've got my Alk over 4.0 m/L and yet my pH won't get about 8.1. I keep adding Alk, and then pH, buffer, but it only drives my Alk higher (at one point 5.6) without raising my pH. Corals look good, but definitely look better if I keep adding pH buffer.

I even turned my calcium reactor off completely for 3-4 days because I thought maybe the effluent was dragging this down. That still could be the problem, but I don't know how to nail this down.

Any ideas? How do I raise my pH if my ALK is already high????

btw, I use Salifert test kits. My maintenance guy uses SeaChem and got considerably lower readings for Alk and CA than I got. He guessed that my kit was probably correct.

HELP!!!!!!!!!!!

[zhenya]

Have you read through this article?

http://www.advancedaquarist.com/issu...e2002/chem.htm

Have you checked for possibility of perhaps higher concentration of CO2 in the house? Also, how do you check your PH values? If with a monitor do you calibrate your probe regularly?

[Stappercrab]

Very helpful, thank you! I'm convinced my measurement of pH is accurate, but the lower pH is likely still within an acceptable range, and definitely wasn't an issue until I started to get my calcium reactor up-and-running. In hind-sight, it seems pretty obvious. In any event, I'll toy with limewater and continue to monitor my ALK.

Thanks a bunch for replying! This board is really terrific.

steve

[zhenya]

Hi Steve,

Sorry I forgot to welcome you to the board....Welcome!

FWIW, I too run calcium reactor and my Ph flactuates at light out period. Usually it's 7.8 at night and 8.2-8.3 during the day, I had no problems with it so far but we had discussed this issue here previously and there are few other things that can be done aside from adding limewater.
Rigging up a reaction chamber where your effluent goes prior to entering your sump/display is another way of increasing Ph of effluent. You can simply rig up a soda bottle and run a airline tubing in there with a small air pump( just to bubble it up a bit and blow off some excess CO2). Try searching this forum and I think you can find a thread or two discussing this problem.

[tatuvaaj]

As zhenya already mentioned, most pH problems seem to be caused either by a inaccurate test or high CO2 inside the house.

If your house has elevated CO2 levels or you add CO2 to the tank water by using a CaCO3 reactor, no alkalinity ("buffer") additions are going to help The best solution in many cases is to improve the air exchange inside the house and/or use a system to blow of the excess CO2 from reactor effluent (as zhenya described).