PH dropped to 7.8 after a water change.

[2639]

I changed 4 gallons this morning using ro/di water and afterwards, I tested the quality of the water. My ammonia went up from 0 ppm to .25 ppm and my PH went from 8.2 to 7.8

I added some Kent Superbuffer dkh per the instructions. Is this what I should have done or would the PH have risen by itself?

I'm using Oceanic salts btw.

[Doctor_Reef]

You will need often to buff ro/di water... I buff it before adding salt to it!!

[2639]

How would I test that before salt? Will I need a freshwater ph kit?

[Doctor_Reef]

I use a product called reef builder...it puts back the good stuff that ro-di removes...it doesn't overshoot the 8.3 ph....

You can certainly add the salt first and then test ph...add the buffer then...

[cich1]

where did the ammonia come from? is this your new ro/di unit? did you toss out the first few gallons of water after you hooked it up?

[2639]

The first 18 gallons to be exact! My daughter dropped a spoon of milk in the container and I decided to dump that. LOL The only new additions I have are chaeto. I'm thinking there might have been a little die-off of pods or something. But...my test kit is color-based and I could have mis-read the ammonia. The nitrate test is the worst at being able to determine color!!!

I have been testing twice if I suspect a bad read but did not test twice this last time.

I would like to try that product that Doc suggested after I run out of the buffer I used. I have several chemicals and what-nots that came with this tank when I bought it.

[Doctor_Reef]

Reef Builder is made by seachem... Very good product!!!

[NaH2O]

A quick question - was the water change water mixed with salt? I know the question seems silly, but I couldn't decide based on the first sentence of your post if it was straight RO/DI or saltmixed RO/DI. I'll assume it was salt mixed....did you check the pH of the water prior to putting it in the tank. Also, how long was it mixing for prior to the water change? Was the temperature of the water the same as the tank, and what was the salinity?


You will need often to buff ro/di water... I buff it before adding salt to it!!


You don't need to do this. From the article Reverse Osmosis/Deionization Systems to Purify Tap Water for Reef Aquaria (http://www.reefkeeping.com/issues/2005-05/rhf/index.php) by Randy Holmes-Farley:


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).

[gman0526]

Interesting quote Nikki, TY.

[cich1]

when i get a new bag of salt i always test the first batch of water i mix up just to see where its at, you would be suprised how much the sane brand can vary from batch to batch

[2639]

Nikki, the only thing I checked was salinity. :oops:
Ron, that's a good and interesting point. I'll be switching to Instant Ocean as soon as this bottle of Oceanic is gone. I've concluded that IO is better. :)

[2639]

Oh, btw Nikki, it was saltwater, not freshwater. Sorry for not clarifying that :D

[2639]

I plan to get an 18 gal storage container and have it full of saltwater mix...I won't need a heater cause it's going in my garage where it's 90F all the time LOL...I will get a powerhead today from the LFS (yuck) and let it sit for a week at a time...Is a week long enough to ensure proper settling?

[NaH2O]

A week is plenty of time. I normally mix mine 24-48 hours ahead of time, but have been known to leave it for a week.....like last week :D.

I agree with cich1 - I also test a new bucket/batch for Calcium, alk, pH, Mg at a specific salinity. It's a good indication of what you will have to deal with. You can also supplement your mix water to balance it with the tank.

Hope this helps!

[Doctor_Reef]

A quick question - was the water change water mixed with salt? I know the question seems silly, but I couldn't decide based on the first sentence of your post if it was straight RO/DI or saltmixed RO/DI. I'll assume it was salt mixed....did you check the pH of the water prior to putting it in the tank. Also, how long was it mixing for prior to the water change? Was the temperature of the water the same as the tank, and what was the salinity?


You will need often to buff ro/di water... I buff it before adding salt to it!!


You don't need to do this. From the article Reverse Osmosis/Deionization Systems to Purify Tap Water for Reef Aquaria (http://www.reefkeeping.com/issues/2005-05/rhf/index.php) by Randy Holmes-Farley:


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).


Yep...I am aware of the article but it is primarily taliking about replacement water...not make up water that is in a much larger volume...I don't agree...If he is talking about make up water because there is a lot more volume ... He is very good on a lot of things but this has not been my experience at all... I have had to buff the ro water because of the elements that are taken out it won’t hold the ph after time... From what I have seen and heard from others that if the salt mix isn't compensating for the loss then buffing is essential...That is why the manufactures are making money on replacement buffing products for ro/di water…. :)

[Doctor_Reef]

Oh by the way I don't always agree with the big name guys... :)

[2639]

A little clarification here. The water was replacement. I replaced 4 gallons and tested the water in the display tank.

[MikeS]

lets clarify this a bit....Ron, are you referring to RO/DI water that is intended for salt mix, or makeup water for evaporation replenishment?

Mike

[2639]

yeah, lets start over! LOL
When replacing evaporated water, will that need to be buffed? Will the water used for a water-change need to be buffed?

[MikeS]

Evap water....no, does not need to be buffered, but if you have a tank that has a high Ca/Alk/Mg uptake, than using a RO/DI prep mix may help that out a bit, as long as said mix doesn't cause balance problems.

Salt Mix....depends entirely on the salt mix. Those low in Ca/Alk/Mg may benefit from some added prep mix. If your salt mix is low in just one area or significantly out of balance, you may need to adjust just that one area, rather than add a prep mix.

On the pH...salt mixes tend to swing up and down quite a bit when freshly mixed. Let it sit for a day or two, then test the pH. If it is low, try adding an airstone for 24 hours and see what happens. If this does not raise the pH, then try adding a buffer and use the airstone.

It's important to remember...a "buffer" does not permenantly raise the pH, it stabilizes it.

MikeS

[2639]

I need to get test kits for the other elements as well so I don't accidentally overdose those. Am I right?

[MikeS]

yeah, you should....

In a new tank, your Ca/Alk/Mg demands are probably pretty low....water changes should be more than adequate to keep these in a good range. If you are going to start tampering with them, however, you need a test kit...

Mike

[Doctor_Reef]

lets clarify this a bit....Ron, are you referring to RO/DI water that is intended for salt mix, or makeup water for evaporation replenishment?

Mike

This is what was stated...
"I changed 4 gallons this morning using ro/di water and afterwards, I tested the quality of the water. My ammonia went up from 0 ppm to .25 ppm and my PH went from 8.2 to 7.8"

When you do a water change that is mixing up salt???? If it was just ro/di water I am not sure what that was...I was under the impression that it was a water change not just topping off evaporation...

I wasn't under the impression it was just evap water...I thought he was talking about make up water intended for salt mix...You don't buff replacement water for evap water you shouldn't ever have to buff that... Sorry if I wasn't clear on that... as you said it depends on the salt mix...I know my salt mix that I use and I need to add some buffer to prepare it for the tank...

[2639]

LOL...seems this thread got a little confusing :oops:

[Sugar Magnolia]

LOL. Don't worry Andy, water chemistry can be very confusing.

I see your numbers are back to zero and your pH is back up. What's the NT mean for salinity?

[NaH2O]

What I'm confused about though, is why you are buffering the RO/DI prior to the salt mix.....you don't know what the pH will be until after the water has been mixed, right? Essentially, even the same bucket of salt could yield different parameters based on an uneven distribution of components.

[2639]

I used 'NT' for Not Tested.
I believe using a buffer will cause the ph to go where you want it regardless of if it's high or low.

[cich1]

why aren't you testing your salinity?

[2639]

I didn't do it last night because I'd just topped off the evaporated water and didn't wanna wait for the water to completely dilute..I was TIRED so I went to bed LOL

[2639]

Oh, and I can't stand my hydrometer! I'm gonna get a refractometer soon. That way, i don't have to fool with airbubbles!

[Sugar Magnolia]

This is a great refracto at a great price. http://www.premiumaquatics.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=REFRACT-PA&Category_Code=Hydrometer

[Doctor_Reef]

Agree with SM....very atractive price and sweet refracto!!!

[FishinInTheDark]

That's the one I had. (Sure wish I hadn't dropped it in the driveway when we moved.) It worked great.

[cich1]

i have the same one, been using for over 1 1/2 with no problems.
I started with a refractometer but after the first week i got so aggravated with i tossed it in the trash

[2639]

That IS a nice looking unit...I believe I will buy that.

[Doctor_Reef]

You won't go wrong.....;)

[Sugar Magnolia]

I've had mine for about 2 years now. Calibrate it every 6 months or so.

[2639]

I am sure I'll find this out when I get it but what exactly IS calibrating? How do you calibrate a swing arm hydro?

[caseyjaydarling]

does using ro/di for top-off lower the pH? my pH was somewhat low today and i'm trying to figure out why.

[Doctor_Reef]

caseyjaydarling - Just toping off with ro/di water shouldn't lower your ph....

2639 - Andy...as far as I know you can't calibrate a swing arm unit...the Refractometer comes with a solution that has no salt and a calibration screw to calibrate it...not hard at all...I use my ro/di water to calibrate it...don't have to do it very often....

[cich1]

How do you calibrate a swing arm hydro?
use a good hard swing with a big a## hammer :lol:

[cich1]

are you testing ph in the morning? if so ph will drop overnight while the lights are off, try checking in the evening after the lights have been on awhile

[2639]

I agree with the hammer idea! :D:D
I only test right before bed after the lights have been on for the day. Heck, it's the only time I have time! LOL

[Doctor_Reef]

Any time in the day when the lights have been on a few hrs...is good to test PH... From your chart it looks like it is 8.3....that is great....

[2639]

;)

[caseyjaydarling]

so are you saying that ro/di water should have a pH identical to my tank?

[Doctor_Reef]

No....It will vary...but just topping off from your evaporated water is not a large enough volume of water and it shouldn't cause a drop in your over all tank ph...I never buff my top off water... When you mix your salt water for water changes you can check to see what the ph is in the new change water and most of the time I have to buff that water as the ph is low...Some salt mixes you don't have to buff....

[Sugar Magnolia]

FWIW, I have never had to buff my water change water. I use IO salt and my pH stays around 8.2.

[cich1]

i'll second that

[Doctor_Reef]

I know IO has holds the ph... The oceanic has a problem with that...the Kent that I also use doesn't need buffing either as it holds the ph....