Ph control

[Texreefer]

ok i have always run high ph around 8.5 but for the last two days my aquacontroller with (new ph prob) is swinging from 8.5 in am to 11.0 in the afternoon... this cannot be an accurate reading can it? my tank shows absolutley zero signs of distress and nothing on the system has changed that could cause this.. if anything the addition of the Deltec skimmer should have reduced the ph a Bit.. any suggestions

[JimD]

If youre using kalk, dip the probe in the solution and see if the reading stabilizes at around 12.4, this should give you an indication of whether its the probe or something going on in your tank.

[Texreefer]

good idea jim i will try that

[Texreefer]

ok put the prob in my kalk reactor and it went straight to 12.3 and stopped.. so i guess ph prob is reading correctly,, i am going to tak the reactor off line for now till i can determine what the problem is.. i amy go ahead and add 200ml of vinegar to the tank to get the ph down a bit

[Texreefer]

OK,, my CO2 had stopped flowing into my CA reactor for whatever reason, so i was not putting CO2 into the system, meanwhile my topoff water was all through the Kalk reactor(which is usually not a problem with CA reactor running right) i got the Kalk reactor off line temporarily and fixed the CO2 input into the reactor.. i put 200ml of vinegar into the system and will do that again this evening and hour or so before the lights go out. that should drop me to around 9.5 .. i will check again tomorrow and dose one more time if needed.. just thought i would share!

[JimD]

Glad you found the probem. A Ph of 11.0 would have definately taken a toll on your stuff.

[Texreefer]

now i'm at a total loss :angry i'm back up to 11.8 after the vinegar addition.. i don't want to just keep dumping vinegar in.. maybe i will try some baking soda later..any ideas on causes or cures?

[hobogato]

wait. check the pH with a chemical test kit before you add anything else. make sure it isnt something funny going on with the aquacontroller.

[JimD]

That and keep both the reactors off and give it a chance to come down on its own. If the controller is working properly, you should start to see it slowly drop. Vinegar is a very temporary fix. Give it time and check it again in a few hours.

[Texreefer]

Thanks Ace and Jim.. i am doing all those things!

[LoneStar]

Do you have any calibrating fluid? Or did you calibrate the probe when you first got it? Usually you calibrate the probe using a solution set at 7 and then a different solutions set at 10.

[LoneStar]

Plus throughout the day the pH will rise and fall. Usually when the lights are on it rises and when they turn off it will fall. But not as much as you have been reading ;)

[matt]

I really doubt you have a tank ph of 11; that's 1000 times as basic as 8. I'm pretty sure all your animals would be dead, and I believe (could be wrong about this but I don;t think so) that you'd have a massive precipitation of calcium carbonate, as the capacity of ionic solution of Ca and CO3 is ph dependent. That's why calcium reactors work at a low ph.

I'm also certain that dripping KW for all your evaporated water would not push your ph anywhere near that high, as literally thousands of tanks have used KW for decades without problems.

So, I would bet the farm that your ph measurement is really off. You should do as Ace says, plus check calcium and alk. How do your inhabitants look? If they look okay, I would not add anything to the system until you get reliable numbers for Ca Alk and ph.

BTW, a "safer" way of lowering ph is with seltzer water; it introduces CO2 directly into your tank without increasing the organic load like vinegar. But I would not do anything until you figure out what your real ph is. One of the most common topics on the reef chemistry forum on RC is about wacky ph readings and just about every time it's due to inaccurate measurement.

[Texreefer]

Everyone , thanks for the input,,i agree with and am aware of all the assumptions and suggestions stated above,,,that is why i was questioning it. i new it could not be that high,, i discontinued the kalk temporarily because my ph usually runs high and i did not want to add to the problem until i get the probe calibrated correctly,, (which is what the problem is) everything in my tank looks great and i do know about the Seltzer but all i had on hand was vinegar( which i use with caution and it only lowered my ph by .5 according to test kit,, whats great about this site is if i didn't know all this, you guys would be steering me in the right direction. :)

[Texreefer]

just a side note.. when i got home today my ph was reading 4.9 :blink :roll

[JimD]

Huh? lol, thats crazy! I wonder why it read the kalwasser correctly? Strange.

[matt]

If your Ca and Alkalinity are normal and your tank has really good air/water exchange, like a good skimmer and good water movement through a sump, and your house is not overly filled with CO2, your ph will almost always be within a normal range. If you're dosing KW slowly and only replacing 1-3% of tank volume per day, it will not raise your ph above normal range. With sufficient alkalinity, ph in reef tanks is always determined by dissolved CO2 content.

You probably already know that!

[Texreefer]

not everyone knows this stuff and i cane use a reminder every now and then ,,, good info as always,, BTW i just calibrated the probe and it is still reading 4.9 so i'm thinking defective probe? i have already contacted Marine Depot for a possible course of action

[JimD]

Could EMI (electro magnetic interference) possibly be the culprit? Is the controller a new addition? Sounds like you got a bum probe.

[Texreefer]

No EMI the conroller is new as well as the probe

[Headless_donkey]

Have you tried the chemical test?

[Texreefer]

yes, testing at 8.1

[Texreefer]

Jim D. wins the Prize.. it EMI i talked to people at marine depot and the probe cable is unsheilded. so i took the controller to my kitchen tabke where there is no other electrical and took some tank water and stuck the probe in,, 8.01ph.. right where it should be.. now how to relocate all my wiring so this thing will work

[JimD]

Well wuddya know.... Whoda figured. I really wonder why they would purposely use an unshielded cable for that application, dont make much sense does it!

[Texreefer]

No it doesn't,,, specifically it is when i plug my computers serial cable into the Aquacontroller.. they plug in right next to each other so i need to find a way to sheild one or the other,, Ace what are you doing? or do you have this problem?

[hobogato]

not doing anything, not having this issue.

[Texreefer]

one last update for those interested:
The ground isolated serial connector (SERIPC9) is used to break ground loops between your PC and the AquaController. In some installations a ground loop is formed when a serial connection is made and can cause erroneous pH and ORP readings. This ground loop can be broken by installing a GISC in the series with the serial cable from the AquaController. If the serial cable is going to be permantly hooked up to the AquaController, then the GISC is recommended. The GISC measures 1.5" x 1.25" x .65" and has one male DB9 connector and one female DB9 connector. Note that the GISC is only for use with the AquaController, AquaController 2 or AquaController Jr.

[hobogato]

i bet that is the black adapter in line on my cable - it was already there when i got it from todd, so i didnt pay much attention to it :)

[Z4]

do a partial water change without adding anything other than salt and see if that will stablize the ph.

[Texreefer]

thanks for the advice Z4,but there is not a PH issue,, the problem was solved in the above posts