Low PH - everything else OK?

[AndySmithers]

I recently got Salifert kits for everything I test (I chose these because of advice on this board).
My old test kits (can't remember which ones now) were always difficult to judge color change etc. One of the things I assumed was reported wrongly was PH - it always came out about 8.0 any time of the day.

However the new Salifert kit reports the same - 8.0.
Other parameters seem OK - Amm.=0, Nitrite=0,Nitrate=1-2,PO4=0,Calc.=380,Salinity=1.025.
I've got clown fish, a fat, healthy yellow tang, reef chromis, brittle star, shrimp, mushroom corals, various polyps - everything seem happy and is growing well.
But I can't seem to get the PH up. I dose everyday with Kalk (I know the calcium is a bit low but I'm slowly getting this up).

I can't really believe that BOTH kits give the same wrong value. Getting the water tested at the LFS is NOT an option (my LFS would have difficulty RECOGNISING water, let alone testing it!).

Any ideas?

 

[fishfreek]

Do you know what your alkinity is? Alkinity and PH are tied together in a really confusing mess of chemistry I have failed to master comprehension of.

The PH level could be affected by oxygen content in the water. Increasing the surface agitation could help with this.

You say you have a PH of 8.0 at any time of the day. Does this include just before lights come on and just before the lights go off?

 

[AndySmithers]

FishFreek,
I forgot alkalinity, didn't I? This measure at about 4.00meq/L.
Is this good?

I've got a fair bit of surface water movement (600PH spray bar), 3 x 270GPH PH's - the surface is pretty turbulent....

As for the PH readings, yesterday's reading was just before lights out in the evening. I've never measured just before lights on, but I'd expect it to be lower then, yes?
I do also run a small sump/fuge with inverse photperiod lights and macro from Hara.

Got me stumped this one, I'm pushing up the Kalk dosage at the moment to get the calcium higher....

 

[lilismom1]

i have a ph monitor about $100 but worth every penny. it's very interesting to watch the readings go up and down. (if your a fish person anyway!) it doesn't help you right now but i'd definately reccomend one.

 

[steve-s]

Any ideas?

Does the main tank have glass lid and do you regularly open a window to allow fresh air into the room? Your problem could be ambient or trapped CO2.

BTW, the kalk will not fix the calcium if the alk is already at 4 mEq/l. You need to use a CaCl additive to raise the Ca independantly...

Cheers
Steve

 

[AndySmithers]

The tank does not have a glass lid. It does have a mostly closed hood with the PC's in but it' ventilated with fans all the time the lights are on.
It's also a pretty big open plan house so not convinced it could be CO2 buildup.

But, can you explain more on the ALK/Ca thing? I've never really got to grips with this part of the hobby.
I actually measured ALK and Ca again first thing this morning. Not sure if it's my technique or real changes but the figures today are:

Ca=380ppm, Alk=3.5meq/L. According to the calculator at Andy's SPS reef this is not in balance but how do I balance this?
Are saying that it matters not how much Kalk I add now, I won't get the Ca up because the ALk is already high? Why?

Confused,
Andy.

 

[steve-s]

Are saying that it matters not how much Kalk I add now, I won't get the Ca up because the ALk is already high? Why?.

Kalkwasser raises/maintains the chemistry in equal amounts. It adjusts both alk and Ca at the same time. So it cannot help bring up the Ca to a balanced level against the alk. You need to use a seperate calcium additive solely first to bring the Ca up to 430 ppm and then once balanced, drip the kalk to keep it there. You may still need to tweek the numbers once in awhile with seperate buffer/CaCl additions though.

Even though you are adding these elements back in a balanced fashion, the consumption of CaCO3 animals in the tank will not neccessarily use them in a balanced fashion. The chemistry is also affected by the skimmer and other equipment in the tank.

Cheers
Steve