Ph keeps dropping

[Corwyn]

Hey group,

Looking for soma advice to figure out why my Ph keeps dropping for the last few days.


I changed my lighting - replaced 10K and 65K 400w to
3 of the new 14Ks from Hamilton. I had the lights down to about 8.5-9 hourrs from the usual 11.

I thought this might be the reason, but I am not sure.
My Ph was at 8.1-8.2 now it's 7.9-8.0 with the light on!

I've been dripping kalc, but it's only been losing about 1-1.5 gallons (maybe ) tank is 180 plus a 65g, 29g and 55g sump.


Corwyn

[Keith Sheridan]

When the lights go off the pH will drop due to resperation of the fish and such changing, I think that's why. Anyway with the shorter light cycle may have something to do with the drop, but it may plateau at a normal pH anyway.

[jimmyj7090]

Just to add to what Keith said, in addition to the decreased daylight cycle, the 14k bulbs are probablly a good bit less intense than the 10k/65k bulbs. Both factors will potentially reduce the normal daytime PH rise. These two factors would seem to me to be enough to cause a .2 change in average PH

Also, how's your alkilinity? If it's low then it is easier for the PH to shift. If you drip kalk without other alkilinity supplementation, it is common for the alkilinity to slowly drop over time.

jk

[Corwyn]

Thanks for the feedback.

I know that the 14ks are not as intense but I upped the total lights from 2 400w and 1 175w to 3 400w. I also lowered the lights by about 4". Of course my brand new electronic ballast just bit the dust after 2 days of use, so I'm down to 2 400w today.

My KH is 10.-10.5. calcium is 500

everything else reads as it should be.
Don't know about salinity, hopefully those refractometers will be here soon. I have 3 different sg meters they all say something different.


Corwyn

[MAS]

I can tell you right off the bat that going to the 14k bulbs from 6500k and 10k bulbs is the cause(assuming everything else in the tank remains constant)for the slight drop in PH since your light output has been decreased. But I still wouldnt be too concerned. PH is still well within acceptabe natural range. Rely less on the test kits and more on how healthy the tank looks. If everything looks and acts healthy, then it probably is.

[jimmyj7090]

I may be off here, but are you sure of the accuracy of your test kits? I think with Ca at 500 and alk at 10Kh you should be pretty close to having a snowstorm (or the levels are perfectly maxed out). All sounds good, but those numbers sound suspect to me. (It's so hard to read some of those dam tests anyway).

Is the PH another point or two lower with the third 400 out of service? This would more or less confirm that it is due to the light changes.

jk

[Corwyn]

Well I used some buffer to bring the Ph up artifically, until I can figure out what the heck is going on. Since the 3rd ballast went down pretty much at the start of the light cycle it's hard to tell.

I tested the Kh with 2 different Tetra kits, they both came up with 9.5 ( I used 10ml of water and it took 18 drops on both test kits.)
I also used a seachem kit that came up at 7 drops.

Ca test I got this afternoon was 450 with a red sea test kit.

Corwyn

[MAS]

Test kits should never be the final means to determine tank health. I also think artificially raising ph is a waste of time. The ocean's natural ph range is 7.8-8.5 so why bother? Especially when alk is plenty high. If alk is high, there is rarely a need to worry about ph.

[Corwyn]

OK, you just confused me! I know that isn't really all that hard, but still.

On the one hand you say that test kits shouldn't be relied on -
and then you say if alk is high then Ph shouldn't matter.

I don't have an alk chrystal ball -so how do I measure it without a test kit? and if I use a test kit then I am relying on it.

The tank looks OK, but not great. I have some green hair algea and some diatom. Some of the corals are doing great, but others are so so.

Frags I got from reefnroll and Greag are doing well and growing.
2 squamata clams are great. Finger leather and xenia - GREAT.
Cup coral and Scroll coral not so great (though I think the later is suffering from the fact that my Chromis' have decided to take up residence in it. )


Corwyn

[MAS]

When I state you shouldnt "rely" on test kits, I mean you shouldnt rely on them to be 100% accurate. They are good for giving a "ball park" figure so to speak.

So when I state that your alkalinity is high(high meaning anywhere from 8-12dKH)and that because of this PH isnt a concern, I am stating a simple fact that high alkalinity and proper ph levels go hand in hand basically. If your alk is reading 8dKH or higher its generally a good sign that your ph is within normal boundaries since high alkalinity is a buffer for ph.

:D
MAS

[Armando]

I never measured or tried to change the ph in my tanks. It doesn't seem to be necessary, so far so good.

[nancysnuwave]

With land plants, when they consume ammonium, the pH drops. Could something be releasing ammonia (new fish, DEAD fish, new food?)

Just a thought.. not sure if rules apply here.. but assume that plant consumation of NH4-N results in the same chemistry in the medium..