ph of RO/DI top off water and other ph issues

themolt · 02/17/2008, 06:41 PM

FYI. I realize I am in no major harm at this point, but I am just a little uncomfortable my ph is not ideal. I also realize there are many ph issue posts so feel free, if I am another one of those people, and respond if you like or not.

ph 7.8 ish
amm, trite, phos 0
trate 20
calc 460
mag 1160
livestock - snails & crabs
filtration - LR, filter floss
refugium w/ chaeto on reverse light
MH light 9 hrs a day

My API kit reads the ph of my top off water (RO/DI water from LFS) at lower than 7.8 (based on my API ph test kit). It is a bright yellow. Is this normal?

Additionally
My saltwater (from LFS) for water changes is around 8.0, but hard to tell with color kit (I am getting a ph monitor).

I've read all the articles on ph and done the aeration test. It went up with outside air so I have excess CO2 in my apt. No calc reactor in my set up. Refugium with reverse lighting.

Not sure if I need to use kalk (same as limewater?), or washing soda, or 2 part calc/alk or something else. This is where I get lost as I am just a beginner. I have not seen any specific instructions on how to add any of these. Also, I want to avoid these marine and ph buffers as I hear they cause more harm than good.

Just curious if there is something that is easy and affordable for a beginner to do. Point me to a website with some beginner instructions and I would be happy. If there is not anything simple, I will let be.

Mavrk · 02/17/2008, 08:01 PM

You cannot accurately take the pH of RO/DI water without very suficticated equipment (even then there really is no point to do so). It is neutral.

What time of day did you take the pH of your tank? Were the lights on or off? Have you tried opening a window and see if that makes a difference?

Your magnesium is low. It should be 1250-1350 ppm (basically 3x your calcium). What is your alkalinity?

themolt · 02/17/2008, 08:13 PM

tested ph during main lighting and it could possibly be 8.0, but hard to tell with colors. usually test 2+ hours after lights go off and its 7.8.

too cold to open a window these days.

alk is ~8 dkh

according to this red sea mag test my magnesium is dead on with my salinity. i am not a magnesium expert, so i do not know what the proportions should. i trusted red sea's table in their kit with has proportions of sg and the according magnesium.

Mavrk · 02/17/2008, 08:40 PM

Quote:

Originally posted by themolt
according to this red sea mag test my magnesium is dead on with my salinity. i am not a magnesium expert, so i do not know what the proportions should. i trusted red sea's table in their kit with has proportions of sg and the according magnesium.

Become an expert... Read up

http://www.reefkeeping.com/issues/2004-05/rhf/index.php

Billybeau1 · 02/18/2008, 01:19 AM

themolt, pH is a very complicated issue.

I love the API kits for testing pH but if you are going to keep a reef tank, you will probably want to purchase an electronic pH probe, like a Pinpoint.

You are probably ok at 7.8 , but you should not concern yourself with the pH of either your top off water or your water change water.

What is important is what is the pH of your tank.

If it is low, then CO2 is almost always the issue. And since you read Randy's articles about Low pH. you should have a handle on that now.

Randy Holmes-Farley · 02/18/2008, 07:40 AM

I've read all the articles on ph and done the aeration test. It went up with outside air so I have excess CO2 in my apt. No calc reactor in my set up. Refugium with reverse lighting.

So the only really good choices are more fresh air in the home, or limewater. Using a high pH two part can also help. Macroalgae can also help, but only when lit.

Randy Holmes-Farley · 02/18/2008, 07:42 AM

I discuss the lack of importance of RO/DI pH here:

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

from it:

http://www.reefkeeping.com/issues/20...hf/index.php#8

Final Effluent pH

Aside from the issues discussed above concerning the effluentâ€™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 aquariumâ€™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 6â€™s and even into the 5â€™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 5â€™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 kitâ€™s indicator dye is enough to alter pure waterâ€™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 pHâ€™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).

themolt · 02/18/2008, 11:55 PM

Quote:

Originally posted by Randy Holmes-Farley
I've read all the articles on ph and done the aeration test. It went up with outside air so I have excess CO2 in my apt. No calc reactor in my set up. Refugium with reverse lighting.

So the only really good choices are more fresh air in the home, or limewater. Using a high pH two part can also help. Macroalgae can also help, but only when lit.

i am going to look into limewater and the research on it. from reading other articles it seems to be the best way.

i have macroalge (chaeto) in my 2nd chamber light at night when main tank lights are off. only thing is i have had it in this set up for about 7 days and it does not look any bigger. using toms power compact 18w hang on back light. do not know kelvin rating.

thanks for input

Randy Holmes-Farley · 02/19/2008, 07:07 AM

Sounds good. This article has more on limewater:

What Your Grandmother Never Told You About Lime
http://reefkeeping.com/issues/2005-01/rhf/index.htm

02/17/2008, 06:41 PM	#1
themolt Registered Member Join Date: Jan 2008 Posts: 55	ph of RO/DI top off water and other ph issues FYI. I realize I am in no major harm at this point, but I am just a little uncomfortable my ph is not ideal. I also realize there are many ph issue posts so feel free, if I am another one of those people, and respond if you like or not. ph 7.8 ish amm, trite, phos 0 trate 20 calc 460 mag 1160 livestock - snails & crabs filtration - LR, filter floss refugium w/ chaeto on reverse light MH light 9 hrs a day My API kit reads the ph of my top off water (RO/DI water from LFS) at lower than 7.8 (based on my API ph test kit). It is a bright yellow. Is this normal? Additionally My saltwater (from LFS) for water changes is around 8.0, but hard to tell with color kit (I am getting a ph monitor). I've read all the articles on ph and done the aeration test. It went up with outside air so I have excess CO2 in my apt. No calc reactor in my set up. Refugium with reverse lighting. Not sure if I need to use kalk (same as limewater?), or washing soda, or 2 part calc/alk or something else. This is where I get lost as I am just a beginner. I have not seen any specific instructions on how to add any of these. Also, I want to avoid these marine and ph buffers as I hear they cause more harm than good. Just curious if there is something that is easy and affordable for a beginner to do. Point me to a website with some beginner instructions and I would be happy. If there is not anything simple, I will let be. Last edited by themolt; 02/17/2008 at 07:18 PM.

02/18/2008, 07:40 AM	#6
Randy Holmes-Farley Reef Chemist Join Date: Apr 2001 Location: Arlington, Massachusetts Posts: 86,233	I've read all the articles on ph and done the aeration test. It went up with outside air so I have excess CO2 in my apt. No calc reactor in my set up. Refugium with reverse lighting. So the only really good choices are more fresh air in the home, or limewater. Using a high pH two part can also help. Macroalgae can also help, but only when lit. __________________ Randy Holmes-Farley Current Tank Info: 120 mixed reef

02/18/2008, 07:42 AM	#7
Randy Holmes-Farley Reef Chemist Join Date: Apr 2001 Location: Arlington, Massachusetts Posts: 86,233	I discuss the lack of importance of RO/DI pH here: Reverse Osmosis/Deionization Systems to Purify Tap Water for Reef Aquaria http://reefkeeping.com/issues/2005-05/rhf/index.htm from it: http://www.reefkeeping.com/issues/20...hf/index.php#8 Final Effluent pH Aside from the issues discussed above concerning the effluentâ€™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 aquariumâ€™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 6â€™s and even into the 5â€™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 5â€™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 kitâ€™s indicator dye is enough to alter pure waterâ€™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 pHâ€™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). __________________ Randy Holmes-Farley Current Tank Info: 120 mixed reef

02/19/2008, 07:07 AM	#9
Randy Holmes-Farley Reef Chemist Join Date: Apr 2001 Location: Arlington, Massachusetts Posts: 86,233	Sounds good. This article has more on limewater: What Your Grandmother Never Told You About Lime http://reefkeeping.com/issues/2005-01/rhf/index.htm __________________ Randy Holmes-Farley Current Tank Info: 120 mixed reef

02/17/2008, 08:01 PM	#2
Mavrk Registered Member Join Date: Jul 2007 Location: California - South Bay Area Posts: 2,775	You cannot accurately take the pH of RO/DI water without very suficticated equipment (even then there really is no point to do so). It is neutral. What time of day did you take the pH of your tank? Were the lights on or off? Have you tried opening a window and see if that makes a difference? Your magnesium is low. It should be 1250-1350 ppm (basically 3x your calcium). What is your alkalinity?

02/17/2008, 08:13 PM	#3
themolt Registered Member Join Date: Jan 2008 Posts: 55	tested ph during main lighting and it could possibly be 8.0, but hard to tell with colors. usually test 2+ hours after lights go off and its 7.8. too cold to open a window these days. alk is ~8 dkh according to this red sea mag test my magnesium is dead on with my salinity. i am not a magnesium expert, so i do not know what the proportions should. i trusted red sea's table in their kit with has proportions of sg and the according magnesium.

02/18/2008, 01:19 AM	#5
Billybeau1 Registered Member Join Date: Jul 2005 Location: Dyer, Indiana Posts: 12,010	themolt, pH is a very complicated issue. I love the API kits for testing pH but if you are going to keep a reef tank, you will probably want to purchase an electronic pH probe, like a Pinpoint. You are probably ok at 7.8 , but you should not concern yourself with the pH of either your top off water or your water change water. What is important is what is the pH of your tank. If it is low, then CO2 is almost always the issue. And since you read Randy's articles about Low pH. you should have a handle on that now.