View Full Version : Another PH issue, it's going up to 8.6 ?
kware
07/01/2009, 07:46 AM
My PH starts the day around 8.1. Then when my halides come on (2 pm ) the PH goes up to 8.6. I've been shutting my lights off early so my PH doesn't go up any further. Anybody have any experience with this or a remedy.
Henry Bowman
07/01/2009, 08:07 AM
My first curiosity is what is the alkalinity in the tank ? My bet is that the reading is pretty high.
You "can" lower pH with soda water. It contains Co2 which will drive the pH down. "IF" you do use it, go VERY slow. Often the pH will not drop in the first few additions then it will drop like a rock. Depending on the size of your tank, it may only take a few ounces. You dont want to lower the pH more than .1 within a 18-24 hour period of time. You should be prepared to measure pH and alk every time you add soda water.
The real issue is why the pH is so high to begin with. Again, check your alk. The soda water will also cause the alk to drop.
Using soda water can be risky. You need to make sure you get soda water with no salt or other ingredients and go very slowly.
In the long run, you can put macro algea in a refugium and run it on a reverse light cycle to keep the pH from swinging largly from day to night.
Others will probably weigh in on this issue and my resolution will probably be somewhat controversial. I have used this method. When I returned from vacation, my tank sitter had added toooo much buffer to the tank. Corals were tip burning from to much alk to fast. My alk was 16 dKH, the pH was 8.5 . I lowered both by adding the soda water over 2 days, testing constantly. My pH came down to 8.3 and alk came down to 13. I let the alk come on down naturally over the next week.
kware
07/01/2009, 12:36 PM
Actually my alc has been low , around 5 to 6. I thought about adding baking soda to bring alk up and lower the ph. What do you guys think?
How are you measuring your pH? With a probe? A test? It's possible you're getting an erroneous reading.
aquaman67
07/01/2009, 02:30 PM
<a href=showthread.php?s=&postid=15288289#post15288289 target=_blank>Originally posted</a> by Paco
How are you measuring your pH? With a probe? A test? It's possible you're getting an erroneous reading.
+1
Nothing worse than chasing bad numbers.....
kware
07/01/2009, 02:39 PM
I have a pinpoint PH probe. It hasn't been calibrated in about 4 months though. It should still be accurate. Although I did take the probe out and clean it with vinnigar. Should I calibrate it now?
rgrobe
07/01/2009, 02:44 PM
I calibrate my pinpoint monthly just to make sure. Several months ago I had a similar problem. Ph up to 8.6. When I did recalibrate my Ph was actually 8.1. I do it with my monthly maintenance now. May not be your problem but it is an easy thing to do just in case.
High pH is a rare problem -- I'd suspect bad calibration before I started making weird changes to your tank. That's just me.
kware
07/01/2009, 03:24 PM
I just ordered calibration fluid. I still think my probe is accurate though.
IslandCrow
07/01/2009, 04:24 PM
I truly doubt your probe is accurate after 4 months. It's just a matter of how far off it is. My guess would be not much more than .2 off, though, but if it's high, that could be your problem right there. Like rgrobe, I calibrate both of my PH probes monthly, and they always require adjustment. If I haven't calibrated it in over a month or two, I really don't trust the readings. I'll use them to monitor PH swings, but that's about it.
Next question, are you adding any chemicals to the tank. Unless you have a severe algae outbreak, it's rather rare for PH to be too high unless you're adding something that's raising it, like kalkwasser.
aquaman67
07/01/2009, 08:07 PM
I calibrate the $500 pH meter at work once a week and it's always off. Not by much but after a month or so I'd never trust it.
The best thing to clean a pH probe with is toilet bowl cleaner with hydrochloric acid in it.
kware
07/02/2009, 05:09 AM
I'm not dosing any chemicals. But I haven't calibrated the PH meter since I got it about 6 months ago. I didn't know that they are so finicky. It does make me nervous though. Yesterday I kept my halides off all day. Should I not worry about it until I calibrate the probe?
Capt_Cully
07/02/2009, 05:44 AM
How does the stuff in the tank look?? Be careful not to treat the numbers. Are corals open/polyps out??? Looks like the corals you have are pretty tolerant species. Try bringing a sample of water to an LFS and have them test it for an unbiased reading.
kware
07/02/2009, 07:49 AM
All the corals look pretty good. That's a good idea. Think I'll call Tim at ABC reefs.
IslandCrow
07/02/2009, 04:44 PM
If you're not dosing anything, I'm almost certain it's a miscalibrated probe, so I wouldn't worry too much right now. I'd even turn the halides back on. . .at least for 3-4 hours a day. It's extremely rare to have high PH problems if you're not dosing anything.
I agree with everyone else, calibrate your probe before you do anything. With an alk reading that low it is doubtful your ph is that high. After you calibrate the probe you will probably find that your Ph is actually low and want to do something to raise it. Using vinegar to clean it, which is really low Ph, then putting it back in your tank surely threw the calibration off.
Shablin
07/02/2009, 11:11 PM
I also agree with everyone else; having worked in several pharmaceutical company research and private labs, we were required to calibrate the pH meter before EACH use and document that it was done. This is considered standard for these; I cant say how ofter yours needs calibration (each make and probe is different) but I guess about once per month and especially if there is a strange reading like this.
kware
07/03/2009, 05:18 AM
I ordered PH calibration fluid and left my halides on all day yesterday. It did make me nervous yesterday though , my PH meter read 8.7 at the end of the day.
Reefski's
07/03/2009, 05:32 AM
he is getting a swing in pH which is not just a meter needing calibration. my pintpoint meter reads high when then battery needs to be changed.
his low alk is contibuting to the swings. 5-6 is very low.
slowly bring it up slowly over a week or more dosing baking soda dripped into the tank and i bet your problem is solved.
Carl
kware
08/04/2009, 05:09 PM
Well I just got around to calibrating my PH meter. Everybody was right. With my newly clibrated probe my PH reads 7.8 in the morning and 8.1 at night. Now I am concentrating on raising my alc without a skyrocked PH reading.
Reefski's
08/04/2009, 06:31 PM
soda carbonate, not bicarb will raise it.
sedor
08/04/2009, 07:41 PM
Its normal to have a pH swing between lights on and off. Some people try and maintain pH by dripping kalk on a controller when the pH drops below a certain level. With your probe reading the way it should I wouldn't even worry about those numbers.
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