Question on GFO use and low PH

[aviator300]

This is kind of a 2 part question so lets talk about my pH first.

 

Ever since I've started reefing about 2 years ago I have had low pH. I use RSCP salt and distilled water and my pH usually hangs around 7.7 but drops to 7.55 at night. I have lived in 3 different parts of the country and have used 3 different brands of DI. I always have my windows cracked a bit to avoid Co2 buildup but pH remains low. I have used Kalk in my ATO before which maintains my pH at about 8.0 during the day but have not used that in the last year. I have never "chased" my pH or been obsessed with it because I realize that stability is more important than numbers but I have noticed most folks report pH in the 8.0 + range and I wonder what the difference in their tanks and mine may be (salt, water, etc)?

 

The second question is related to the first as follows. About a week after I set up this tank. http://www.nano-reef.com/topic/371618-aviators-cadlights-zen-5-oooops-bryopis-or-algae-already/?p=5286732

My Phosphate level was 0.25 so I added a small bag of GFO to the HOB filter and after 3 days I could not detect any PO4 at all but my PH has dropped from 7.9 to 7.5. I read that GFO can cause a PH drop so my question is should I remove the GFO after the PO4 drops and just use it periodically, or should I just leave it in and deal with the lower PH

[dutch27]

If your ph is consistent and your corals look healthy, I wouldn't worry about it. Many many people run GFO 24/7 in reactors just fine. A night time drop is also normal, I wouldn't worry about cracking windows at night either. I live in the northeast, no pH drop is worth cracking a window in February, lol.

[ManGups]

Consistent Ph lower than 7.8 supposedly makes it difficult to calcify so generally it should be above 7.8 and not vary 0.2 during a day. If it falls below 7.8 during the night for a few hrs - don't worry as long as ur corals look okay and u have growth

 

What is your alk at.. ? Higher alk also boosts ph. Alk anywhere between 7-11 dKH is good. Some run it at 9. I have found dKH of 7 ~ 7.5 good enough for me and good growth. As a result my pH runs lower - 7.8 ~ 8.1 ( that is lowest and highest over a period of days) and does not vary more that 0.2 a day.

 

You can increase pH by either using a chaeto in the opposite cycle to reduce CO2 during the night and thus preventing the pH to drop. I am ruining a cheato so it helps .. I also started running a CO2 scrubber to boost my pH.

 

A CO2 scrubber basically reduces CO2 in the intake of the skimmer if u run one. It is pretty easy - just search google.

 

I cannot say about GFO and pH relation. I run GFO all the time in small quantities but donot see any effects on pH when I refresh it no-weekly.

[aviator300]

Consistent Ph lower than 7.8 supposedly makes it difficult to calcify so generally it should be above 7.8 and not vary 0.2 during a day. If it falls below 7.8 during the night for a few hrs - don't worry as long as ur corals look okay and u have growth

 

What is your alk at.. ? Higher alk also boosts ph. Alk anywhere between 7-11 dKH is good. Some run it at 9. I have found dKH of 7 ~ 7.5 good enough for me and good growth. As a result my pH runs lower - 7.8 ~ 8.1 ( that is lowest and highest over a period of days) and does not vary more that 0.2 a day.

 

You can increase pH by either using a chaeto in the opposite cycle to reduce CO2 during the night and thus preventing the pH to drop. I am ruining a cheato so it helps .. I also started running a CO2 scrubber to boost my pH.

 

A CO2 scrubber basically reduces CO2 in the intake of the skimmer if u run one. It is pretty easy - just search google.

 

I cannot say about GFO and pH relation. I run GFO all the time in small quantities but donot see any effects on pH when I refresh it no-weekly.

Some very good points. Thanks