Balancing Alk, CA and PH

[gwilcom]

I bought a CA reactor and set it up last weekend. For fear of adjusting the wrong parameter and killing everything I need a little assistance pls.

After 2 days readings were
PH 8.8 (normal for my tank but would like it to be lower)
CA 360
alk 11 dKH

Seemed a bit low in CA and high in PH so I dropped the PH in the reactor from an upper limit of 6.8 to 6.6. After 24 hours the readings are:
PH 8.8
CA 380
alk 14 dKH

What do I do to get the PH and alk down but the CA up? CoralLife manual doesn't mention these parameter being out of balance like this and suggests adding a supplement to get the CA up. Seems then I shouldn't have bought the reactor if I was still going to have to add CA manually.

 

[ChrisRD]

The reason the manual is suggesting adjusting the Ca with a supplement is that ideally you want the reactor to maintain your levels, not raise them. The addition of the supplement would just be to get things where you want them initially, or for the occasional tweaking.

If your readings have climbed that much in 24 hours you should probably back the reactor off as it sounds like it's too cranked up. To get alk back down, your best bet would be to shut the reactor for a few days allowing alk to drop naturally and then starting this process over.

Allow alk to drop into the range you want, raise Ca with the suppliment and then fire up the reactor. Tweak the reactor to maintain the levels you're trying to hold.

As for your pH - it's definitely on the high side. I would first try another test kit, or calibrating whatever meter/probe you're using to measure it to ensure you're getting an accurate reading. Unless you're dosing a lot of kalkwasser or doing frequent water changes with a saltmix that has a very high pH, it seems unlikely that it would be that high.

If you know for sure your pH readings are accurate, here's an article that deals with the issue and possible solutions:
http://www.reefkeeping.com/issues/2005-03/rhf/index.php

HTH

 

[gwilcom]

Excellant feedback! I read through the information under the link you provided and know more now about this than I ever expected.

I took my ph probe out of the CA reactor and tested the water. 8.43 So much for chemical test kits and strips. I just calibrated the probe on Sunday so I am pretty sure it's correct.

As the artical stated, don't make a bad situation worse by overcompensating due to inaccurate test results. This is EXACTLY why I asked in the first place. Thanks for your reef saving advice.

 

[rbursek]

What is your Mg level? If it is low it is hard to get Ca up and keep it up.

 

[ChrisRD]

Agreed. Mg plays an important role with Ca/Alk and should be monitored as well...

 

[scifi_3d_zoo]

Oh man... don't mess with those "test STRIPS". Test kits are ok... especially for pH. Just get another one of diff. brand in case you ever question the results.