another low ph problem

[pete79]

i hope you can help me everybody else is stumped?

my ph was always stable until about 4 months ago.
it cant be excess c02 because i put a venturi on my return
pump and skimmer for about 5 hrs today with no change at all
also shutdown reactor again

i have a 75g tank 125g sump/fuge 1.5 yrs old
my parameters are
ph morn 7.7 now 7.9
calc 460
dkh 11
ammo 0
nit 0
mag 1200's

 

[Randy Holmes-Farley]

Low pH with normal or high alkalinity is always due to excess CO2. More aeration does not ensure a lack of excess CO2 because the house air can easily have excess CO2 in it. In such cases, you either need to bring in outside air somehow, or use high pH alkalinity additives to use up the CO2. Limewater is by far the best choice in that regard.

This article shows an aeration test that diagnoses the source of the CO2:

Low pH: Causes and Cures
http://reefkeeping.com/issues/2004-09/rhf/index.htm

 

[pete79]

excess co2

excess co2

<a href=showthread.php?s=&postid=6457401#post6457401 target=_blank>Originally posted</a> by Randy Holmes-Farley
Low pH with normal or high alkalinity is always due to excess CO2. More aeration does not ensure a lack of excess CO2 because the house air can easily have excess CO2 in it. In such cases, you either need to bring in outside air somehow, or use high pH alkalinity additives to use up the CO2. Limewater is by far the best choice in that regard.

This article shows an aeration test that diagnoses the source of the CO2:

Low pH: Causes and Cures
http://reefkeeping.com/issues/2004-09/rhf/index.htm

i read your article about 2 months ago since then ive had my skimmer intake outside with no changes maybe thats still not enough??
where can i get a home co2 test kit??
i also dose kalk every night just to keep 8.0

 

[Randy Holmes-Farley]

There isn't a cheap CO2 in air test kit, but you can buy an expensive meter or less expensive but still pricey testing tubes.

The aeration/pH test in the article ought to be adequate, however.

 

[pete79]

ph hasnt changed

ph hasnt changed

i shut my reactor off last sunday
all this week ive had the window open
added two more fans in basement
aerated tank with outside air
are there any other possible reasons ph would still be low/

i also swicthed back to using 2 part ionic , and when i add it the ph rises to 8.1 for about an hour then goes right back down to 7.9
just like kalk???

 

[Randy Holmes-Farley]

Did you do the aeration test with inside and outside air? That is really the best way to diagnose the situation.

 

[pete79]

test

test

that didnt work either???

 

[pete79]

tap water

tap water

could my towns tap water have any thing to do with this because
my freshly mixed (rodi) salt water reads 7.9 and that seems to be what my tank buffers to
are there any chemicals they might add????

 

[pete79]

Re: tap water

Re: tap water

<a href=showthread.php?s=&postid=6499096#post6499096 target=_blank>Originally posted</a> by pete79
could my towns tap water have any thing to do with this because
my freshly mixed (rodi) salt water reads 7.9 and that seems to be what my tank buffers to
are there any chemicals they might add????

also my tank had a stable ph the first year i had it 8.2 -8.3
the only things i changed were more corals and a few fish
and calc reactor

 

[Randy Holmes-Farley]

that didnt work either???

What does that mean?

The only cause of low pH is a reef aquarium with normal alkalinity or higher is excess CO2. The only question is whether it is only in your tank, or also in the air. A CaCO3/CO2 reactor will drive down pH by adding excess CO2.

 

[pete79]

test

test

i mean i performed the test and the ph didnt change.
my reactor has been off all week

 

[Randy Holmes-Farley]

Outside?

If the pH was below 8 and didn't rise on aeration outside, then there is a pH measurement problem.

 

[pete79]

pinpoint

pinpoint

after inspecting my ph monitor (pinpoint)i noticed a big problem
when i turn light ballast off ph goes up 2 full points? i think thats a problem huh! ill have to get a battery?

but the funny thing is i tested it with some borax like your thread says and it read 9.3 with the ballast left on

 

[Whaledriver]

Your tank is about 1 1/2 year old right? My guess is the buffering capacity of the stuf in your tank (sand and rock) is being used up. I have 2 tanks and they both started haveing ph problems after about 2 years. Is this a reasonable idea???

 

[pete79]

buffering

buffering

i asked that same question before?
but people told me it usally takes years to happen
but i think thats my next step!
first im gonna re calibrate both my ph monitors and run them on
battery power.
i think ive ruled out c02 as the cause
plus ive had this problem since about the end of august
and back then the ac was crancked with the fresh air vent open
so there was prob very little to 0 c02 in the air?

 

[Randy Holmes-Farley]

after inspecting my ph monitor (pinpoint)i noticed a big problem

Pinpoints and someother meters are known to suffer interference from certain aquarium lighjting systems. Try measuring away from them.

Your tank is about 1 1/2 year old right? My guess is the buffering capacity of the stuf in your tank (sand and rock) is being used up. I have 2 tanks and they both started haveing ph problems after about 2 years. Is this a reasonable idea???

Not if the alkalinity is normal. It is the CO2 and alkalinity that determine pH. It is also what determines buffering capacity.
i asked that same question before?
but people told me it usally takes years to happen

There is no such effect.
i think ive ruled out c02 as the cause


How? Elevated CO2 is always the cause of low pH when alkalinity is normal or higher (2.5 meq/L ,or 7 dKH, or more). There is no other explanation ever possible or necessary in seawater.

 

[pete79]

c02

c02

what im saying is i dont trust my ph monitor until i recalibrate it
i dont trust ph kit either the colors are too close!
because with all the aeration ive done this week with no changes in ph readings , whether their accurate or not ,for all i know my ph could be high the whole time!

and why does fresh saltwater read 7.9 with my meter
when everybody else gets 8.2or8.3ph ive been thinkin
the meter has to be reading lower than actual

 

[Randy Holmes-Farley]

and why does fresh saltwater read 7.9 with my meter
when everybody else gets 8.2or8.3ph ive been thinkin
the meter has to be reading lower than actual

Fresh salt water will reflect the CO2 levels in the air as well, and many people do get in the upper 7's after aeration.

Anyway, it certainly is a good plan to double check the meter calibration before doing anything drastic.