PH help needed

[korbynlehr]

Okay I am testing our tank with our PH meter and I get 7.8, I test my RODI water and get 10, and our fresh made saltwater and I get 8, and checked my limewater and it checks at over 10. Can any of this be right? I checked the meter with calibration fluid and it checks fine. We have started dosing with limewater 2 days ago but the PH in the tank is still low. What do you all make of this and what can I do to fix it? Can I do a larger dose of limewater to get it to the PH I want and then drip dose from there on? I obviously need some help here.

[Randy Holmes-Farley]

Yes, it is probably all right if you have recently calibrated the pH meter.

Forget the RO/Di. You cannot accurately read the pH of very pure water with a meter or a kit, and mine happens to read that high too:

Reverse Osmosis/Deionization Systems to Purify Tap Water for Reef Aquaria
http://reefkeeping.com/issues/2005-05/rhf/index.htm

from it:


[[As an aside, my RO/DI effluent always seems to have a high pH (9-10) even before its conductivity rises significantly. While there are many complications to measuring pH in pure water, where pH kits and meters do not function well, I cannot so easily dismiss these readings as being purely artifact, although they may be. I have wondered for years what might be causing it, and have not yet found any clear answer. However, if the above process is happening in my system even on a small scale, it might explain the results (my tap water contains chloramine). A sodium hydroxide solution with a pH of 9 has only 10-5 moles/L of sodium hydroxide, or 0.4 ppm sodium hydroxide by weight. Is that all or part of the high pH that I observe in my effluent? I’m not sure.]]


and

Final Effluent pH

Aside from the issues discussed above concerning the effluent’s pH when the DI resin becomes depleted, the final pH coming out of an RO/DI system should not significantly concern reef aquarists. Many aquarists with low pH problems have asked, for example, if their aquarium’s low pH may be caused by their replacing evaporated water with RO/DI water that they measure to have a pH below 7. In short, the answer is no, this is not a cause of low pH nor is it something to be generally concerned about, for the following reasons:

1. The pH of totally pure water is around 7 (with the exact value depending on temperature). As carbon dioxide from the atmosphere enters the water, the pH drops into the 6’s and even into the 5’s, depending on the amount of CO2. At saturation with the level of CO2 in normal (outside) air, the pH would be about 5.66. Indoor air often has even more CO2, and the pH can drop a bit lower, into the 5’s. Consequently, the pH of highly purified water coming from an RO/DI unit is expected to be in the pH 5-7 range.

2. The pH of highly purified water is not accurately measured by test kits, or by pH meters. There are several different reasons for this, including the fact that highly purified water has very little buffering capacity, so its pH is easily changed. Even the acidity or basicity of a pH test kit’s indicator dye is enough to alter pure water’s measured pH. As for pH meters, the probes themselves do not function well in the very low ionic strength of pure freshwater, and trace impurities on them can swing the pH around quite a bit.

3. The pH of the combination of two solutions does not necessarily reflect the average (not even a weighted average) of their two pH values. The final pH of a mixture may actually not even be between the pH’s of the two solutions when combined. Consequently, adding pH 7 pure water to pH 8.2 seawater may not even result in a pH below 8.2, but rather might be higher than 8.2 (for complex reasons relating to the acidity of bicarbonate in seawater vs. freshwater).





The pH of limewater is likely in the 12's.

The best ways to raise the pH of tank water are with more aeration with fresher air, or by using limewater:

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

[korbynlehr]

<a href=showthread.php?s=&postid=8742195#post8742195 target=_blank>Originally posted</a> by Randy Holmes-Farley
Yes, it is probably all right if you have recently calibrated the pH meter.




The best ways to raise the pH of tank water are with more aeration with fresher air, or by using limewater:

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

Randy,
So with my ph being 7.8 can I remove say 1/2 gallon of water and substitute 1/2 gallon limewater?

[Randy Holmes-Farley]

No. Drip in the limewater to replace evaporation. Adding only 1.25% of the tank volume will boost pH by about 0.6 pH units, so add only a little and add it slowly.

[Agnes]

Randy,
My reef tank pH seemingly going up every day. It seems to increase about 0.2 pH in a day or overnight. I've read that pH will drop at night but mine is doing the opposite.
Before you answer, I'm a technical person not a chemist and my college chemistry classes were a long time ago so I don't remember much without a lot of prompting.
What can be going on?

[Randy Holmes-Farley]

You pH rises at night and drops during the day? Or it rises more each day and night and never drops?

how long has that been going on?

What is the pH now? What was it before?

How are you measuring pH?

If a meter,when was the last time you calibrated it?

[Agnes]

This has been going on for maybe 2 weeks that I'm sure of. I have a Milwaukee pH tester (new and calibrated in the last week) and Red Sea test kit. I've checked with both and they agree. I burned my tank by letting the pH go above 8.8 and am now trying to control it with water changes to keep the reading about 8.4.
I whole thing is a terrible sad story. I recently bought a new light fixture, a pc strip light. Well, it interferes with the tester reading but I didn't know that at the time. When I tested the pH 2 weeks ago it read 6.5!! I panicked and started adding buffer. After adding a great deal of buffer to raise the pH I found the problem and checked the pH to find it was over 8.8. I started doing water changes immediately and trying to flush the buffer out.
I thought the reading would return to normal with the water changes but it hasn't and keeps rising.
I was having trouble keeping the pH up before all of this stupidity and now I'm working the other way.

[mcurl98]

The best ways to raise the pH of tank water are with more aeration with fresher air, or by using limewater

Bear in mind that aeration will tend to lower the pH, so if maintaining high pH is difficult, reducing aeration may help a bit.


The top quote is from this thread and the bottom one from your dinos article. I'm confused. To raise PH, should I aerate more or less?

[bertoni]

Aeration drives the CO2 level in the tank to equilibrium with air. So adding more aeration can move pH up or down, depending on the situation.

If you're dosing limewater to raise pH (due to high indoor CO2 or to increase pH to deal with dinoflagellates), more aeration might lower the pH by adding CO2 to the tank. In this situation, the tank's CO2 level can be less than equilibrium with the air. More aeration increases CO2, which lowers pH.

If the tank is at lower pH because of CO2 production in the tank, aeration would raise it. This problem can happen with a heavy bioload and not much circulation, for example.

[Agnes]

Ok, I'm confused. I thought aeration increased O2 content. How does it add CO2? Nevermind, I get it. All of the gases present in the atmosphere are added/exchanged with the water. This is in proportion to the atmosphere content right?

So if the water has a high CO2 content from the bioload, aeration would bring the level closer to the atmospheric proportions (which I don't remember right now). And this will bring the pH back to the desired level, or closer. The opposite would also be true, if the CO2 is low from low bioload and the pH high then aeration would bring it back to "normal" and the pH drop.

Is this right?

[bertoni]

Yes, the gasses in the air are exchanged with the water, and that's affected by the contents of the air involved. In a house with high CO2 from gas-burning stoves or heating, that can drive the pH down compared to the came tank in a room with a more normal CO2 level.

So, high bio-load can indeed lead to a high CO2 content, and aeration would remove CO2 (and likely add oxygen). Low CO2 is more likely caused by photosynthesis, and more aeration would raise the CO2 and drop the pH back towards more normal levels.

[Agnes]

How would you know if your home has high or low CO2 levels without a monitor? I wonder if I could borrow an O2/LEL, hmmm... but that won't give me CO2.
I'm on the gulf coast, even though I do have gas heat I use it so seldom. Usually, like now the ac is on.
I doubt it's bio-load as I have 4 small fish, a hippo tang about 3", a clown under 2", a small shrimp gobi with pistol shrimp, and a nocturn gobi I never see. This is in a 110 tank with a 55 gal tank made into a refugium that has about 30 gals of water in it.

[bertoni]

I haven't really considered how to measure CO2 levels indoors. You might want to start your own thread on pH problems. I don't think you've posted your measurements, etc.

[Agnes]

I'll go check the pH but the ammonia, nitrites, and nitrates are zero. OK, pH is now 8.6 and time to turn out the lights. The salinity stays at 1.025 and temp between 77 and 79 deg F.

I have a 110 gal with 2 corner overflows. Below that I have an old 55 gal made into a refugium divided into 3 sections by plexi-glass/acrylic. The first section is the sump from the overflows with the heater in it. The middle is the deep sand bed and macroalgae with a powerhead to tumble the macroalgae. Then the last section with the return pump and the pump for the berlin skimmer which sits on the sand bed.
For light I have a Odyssea with 2 150W 10000K MH and 4 21W actinics.
The return water from the refugium is piped to the back and bottom of the tank. There I have a pvc pipe with holes drilled about every inch which means the water comes in at the bottom and goes out the overflows. I also have 4 powerheads in the tank for extra flow; 2 at 236 gph and 2 at 350 gph.
I have probably 100 lbs of live rock arranged in piles at the overflows leaving the center of the tank open. I recently got a pistol shrimp and so have almost all of the crushed coral piled in the middle for him to excavate which he seems to do happily. It never looks the same from day to day.
I have great hopes of having a beautiful tank with time.

[bertoni]

So what's the pH in the morning, before the lights turn on?

[Randy Holmes-Farley]

Agnes:

Have you recently calibrated that meter?

[Agnes]

To bertoni:
The pH was 8.6 this morning before turning the lights on.

To Randy:
Yes, I calibrated the meter last week. I have even contacted Milwaukee about the calibration and followed their procedure. It calibrated fine.

What I'm wondering is: if this is because of putting so much buffer into the system how long will it take to get it out; and can I do anything to counter the buffer that won't hurt my fish and corals; also, if it is a matter of water changes and time as I suspect, what are the concerns of trying to counter the buffering with other treatments (Randy I read your article on treating high pH with seltzer and vinegar) while waiting for the buffers to wear out/go away?

[Randy Holmes-Farley]

Unless you are adding a lot of limewater (kalkwasser) at night, or the alkalinity is super high, I just don't believe the pH is really that high in the AM.

What brand calibration fluid? Some are simply no good.
if you are adding a lot of limewater, try stopping it (or adding less).

if this is because of putting so much buffer into the system

What is the alkalinity?

[Agnes]

I have never used limewater. I have used baking soda but didn't find it did much good. What I've used mostly was Sea Chem Marine Buffer and some Sea Chem Reef Builder. My original thought was to dose my tank regularly to maintain a steady pH and dKH.

I used the buffers that came with the tester - Milwaukee. But tossed them after using because of the cross contamination during calibrating. I have some others from a friend where I used to work. They are industrial lab quality. I haven't used them yet but have enough to use several times.

My 75 gal tank is doing very well and the pH in it is 8.3 to 8.4. The tester always read this tank correctly which is what made me panic with the big (for me) tank. I never thought about a light fixture interfering with the instrument (that's no excuse at all for me, I should have thought of it). The tester is not to blame for the problem, I am. I guess I just have to work my way through it without hurting anything else.

I don't know what the alkalinity is, the reading on the test strips I have is bluer than the highest reading of 300 KH. Is there another method of testing?

[korbynlehr]

Randy,
How long should it take to raise my ph using limewater? We have been dripping 3-4 cups a night and it seems our ph has not raised any at all from our 7.9. Any suggestions?

[bertoni]

Marine Buffer is intended for fish-only tanks. I would stop using it, and run a series of 20% water changes to get it out of your system. It adds borate alkalinity, which cannot be consumed by corals. Buffers are a bad way to deal with pH problems.

[Randy Holmes-Farley]

How long should it take to raise my ph using limewater? We have been dripping 3-4 cups a night and it seems our ph has not raised any at all from our 7.9. Any suggestions?

Thee effect is maximal as soon as you have added it,so if it alone is not adequate, more limewater or more fresh air in your home are the best options.

I don't know what the alkalinity is, the reading on the test strips I have is bluer than the highest reading of 300 KH. Is there another method of testing?

Yes, you need a titration test kit to see how bad the problem of your excessive alkalinity is. Salifert, LaMotte, Seachem, LaMotte, etc.

[korbynlehr]

<a href=showthread.php?s=&postid=8765943#post8765943 target=_blank>Originally posted</a> by Randy Holmes-Farley
How long should it take to raise my ph using limewater? We have been dripping 3-4 cups a night and it seems our ph has not raised any at all from our 7.9. Any suggestions?

Thee effect is maximal as soon as you have added it,so if it alone is not adequate, more limewater or more fresh air in your home are the best options.




Would I be safe in doubling the amount of lime in the limewater and try that for a few days and then adjust from there?

[Randy Holmes-Farley]

You can add up to about 2 level teaspoons per gallon of fresh water, before no more will dissolve. :)

[korbynlehr]

<a href=showthread.php?s=&postid=8766212#post8766212 target=_blank>Originally posted</a> by Randy Holmes-Farley
You can add up to about 2 level teaspoons per gallon of fresh water, before no more will dissolve. :)

Then my option as far as the limewater is to take out some water and add limewater in its place? How much should I try at a time?

[Randy Holmes-Farley]

No, you cannot replace tank water with limewater (the salinity will drop), but you can increase evaporation, such as with fans.

[korbynlehr]

Besides opening my doors and windows is there a way to increase the fresh air in my house to raise the ph in the tank?

[bertoni]

Some people run lines from the outside into their skimmer. I think some have reported good results.

[stogie]

What I did is take a piece of 3/8" tubing through an exaust fan opening in my fish tank room. After reading randy's articles this brought my PH up by 1.5. This tubing runs to my skimmers air input line. It takes about a day for it to totally take effect. I just modded my pump impeller to a mesh wheel. I estimate my pump now is sucking about 3X more air than it did before. I hear this obnoxious sucking sound everytime I park my car which is near the tubing.

[Randy Holmes-Farley]

Some folks even resort to an air exchanger that retains heat, but such devices are expensive.

Air lines to skimmers sometimes help, but often are inadequate since the tank top is still exposed to the high CO2 air.