pH drop confusion

[baldbean]

Hi there.

 

Some stats first:

- 12 long gallon Mr Aqua tank

- Sump: Next Reef NRS-20

- Jaeger 50 W heaters (2)

- Eheim 1048 return pump

- CAD lights nano Skimmer

- Kalk in top off (1/2 tsp for 2 gallons)

 

It has been getting a little colder in my place and I have been noticing that my tank temp has been dipping below my desired range (78 F). It doesn't get too cold, but there are times when the heaters seem like they can barely keep up. My first thought was maybe this is happening because of the low flow through my sump and the heated water is not getting through the system fast enough. So to help get the heated water circulating, I added a small pump/powerhead in the first chamber to mix things up.

 

This morning I noticed that the pH dropped to around 7.8 when it has been steady between 8.0 and 8.2 for the past few months. Could this be due to the water being mixed in the sump? My skimmer has been in there the whole time kind of mixing the water around, so I am a bit confused.

 

I usually take my parameters on Wednesdays (today) and I do WCs on Sundays. Here are the parameters for last week though:

 

Mag: 1380 ppm

Alk: 8.8 dKH

Cal: 430 ppm

 

Attached is a plot of my pH and Temp since my last WC. The spike in the graph on the far left is when the WC occurred. The extra pump was added Nov 18 at around 18:00 (6 pm).

[ghostgr]

Your top off water is rodi? I know rodi water has a ph of around 6.5 so that could be contributing i know it did mine jist added a ph buffer and was good to go.

 

Are you testing your ph first thing in the morning or afternoon or night? At the same time everyday?

[markalot]

Don't worry unless it drops below 7.75 or so. Indoor co2 is the reason and opening a window for just a few minutes can help. Google reef low PH to find various articles on the subject.

 

Never ever use a PH buffer in a reef, it will raise KH rapidly and can harm a lot of hard corals.

[ghostgr]

Don't worry unless it drops below 7.75 or so. Indoor co2 is the reason and opening a window for just a few minutes can help. Google reef low PH to find various articles on the subject.

 

Never ever use a PH buffer in a reef, it will raise KH rapidly and can harm a lot of hard corals.

Even with just adding it to my top off? I havent had a problem with it at all.

[markalot]

Even with just adding it to my top off? I havent had a problem with it at all.

 

Do you know how stable your KH is? It's certainly possible that you lucked into a good combination, I know I've done dumb things before and got lucky. Problem is when you go to adjust a bad idea it gets worse. I suggest using Kalk in the topoff, and not very much, to do the same thing and add Calcium and Alk at the same time.

 

It all depends on what corals you have and how sensitive they are. Google LOW PH REEF and you will find some good articles on PH and Kalk. Keep in mind KH and Calcium are linked together so driving up KH (and PH) with a buffer will tend to drive down calcium. Eventually you may get so far out of balance the tank starts to suffer. Many times doing regular large water changes will mitigate this, but then skip a couple of changes and bam, big problems.

[baldbean]

Your top off water is rodi? I know rodi water has a ph of around 6.5 so that could be contributing i know it did mine jist added a ph buffer and was good to go.

 

Are you testing your ph first thing in the morning or afternoon or night? At the same time everyday?

 

My top-off is RO/DI with 1/2 Tsp of Kalk, I am still trying to work out the dosage. I have been running this much kalk for months because my pH seemed to be stable. When test its usually around 6 pm, after work.I usually just go off of what my probe is telling me in between testing and this morning is was the lowest its ever been.

 

 

Don't worry unless it drops below 7.75 or so. Indoor co2 is the reason and opening a window for just a few minutes can help. Google reef low PH to find various articles on the subject.

 

Never ever use a PH buffer in a reef, it will raise KH rapidly and can harm a lot of hard corals.

 

I did have all my windows shut last night now that i think about it. Kind of surprising that this would have this type of effect, wow. On my last tank the pH would hover between 7.8 and 8.1, and this was normal.

 

It may be possible that the pump to circulate the warm water in my sump is just a coincidence. The pump is off now so I will see how it goes.

 

Thanks for the replies.

[Island]

Don't chase your PH...Plain and simple. I have a IM 30L tank and use an Apex controller with lab grade probes, 4 stage RODI unit, Tunze 3155 ATO with 5ml Kalkwasser in a 5 gallon container, and I do weekly water changes. My PH has never hit over 8.0. It usually stays between 7.75-7.9, and my corals are very healthy. I mostly have LPS corals, but I do have a goniopora that is also doing great. If it ain't broke....Seriously...

 

Don't nuke your tank by dosing and trying to fix something that doesn't need fixing...Oh yea..My Calcium with weekly water changes is always above 400, and my DKH is always around 8-9 and mag is always high. I use a very small amount of Kalkwasser to water ratio as I did not want to go to overboard and precipitate my whole tank with snow. I might up the amount of Kalk soon as I am starting to add quite a bit more corals to the tank...Just my .02 cents

[CronicReefer]

+1 to above. Chasing pH can lead to many problems. If you are staying above 7.8 then I would not worry. pH below 7.6 for a period of time can be detrimental but mine stays about 7.8-8.0 and I keep zoas/LPS/SPS coral that all grow just fine. Keep your alk/calc/mag stable and you will not need to worry about pH.