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Discussion Starter #1
Hi everyone, this is my first thread ever. So help me god if my grammer and proper ettiqutte is wack! Anyway I just switched over to RO water to do top off's in my 90 gal. I tested the Ph just to see what was up and it was at 9. I am wondering if I am going to need to use Ph down or something before i put it in the tank. Or will it naturally come down after adding buffers, aerating... ect. Any opinions would be greatly appreciated.
:beer: Markus
 

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Welcome to the forum. Tell us more about your 90gal. We also like pictures.
 

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Discussion Starter #4
My tank has been running for about 6 months now.
- just ordered outer orbit 48" hood!! 2- 150 watt Double ended 2 135 watt Pc's actinic and 6 moon lights. sweet 24 hour system.
- 30 lbs. live rock
- 4" dsb sugar sized
- prizm pro deluxe skimmer
- 4 maxi jets 1200's
- 20 turbo snails
- 10 blue legged crabs
- 1 red legged
- 2 blue damsel
- 1 yellow tail wrasse
Ph @ 8.3
Ammonia - 0
Nitrite - 0
Nitrate - <10
calcium 250 .. i know its low
Alk - 7dkh
Phosphates- < .10

I did have a slight phosphate problem was at .25 but started using a sponge and it has come down. Base phosphate problem on my tap water. I tested the RO water right when i opened it. I have read that the water is too pure so a ph reading will be innaccurate. But I would like a second opinion on this. I am going reef so I plan on trying to catch the yellow tail wrasse and trade him for something. Sorry i got a little off topic there. I enjoy being formal!! :)

Markus
 

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My PH is high from my water after RO/DI

I hold my water in a bin (44 gal) for 5 days circulated so it will naturally come down to 8.2, I use it for water changes and top off.

This works perfectly, you could fight with ph down or baking soda but letting it sit will be most natural way.
 

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Markus said:
My tank has been running for about 6 months now.
- just ordered outer orbit 48" hood!! 2- 150 watt Double ended 2 135 watt Pc's actinic and 6 moon lights. sweet 24 hour system.
- 30 lbs. live rock
- 4" dsb sugar sized
- prizm pro deluxe skimmer
- 4 maxi jets 1200's
- 20 turbo snails
- 10 blue legged crabs
- 1 red legged
- 2 blue damsel
- 1 yellow tail wrasse
Ph @ 8.3
Ammonia - 0
Nitrite - 0
Nitrate - <10
calcium 250 .. i know its low
Alk - 7dkh
Phosphates- < .10

I did have a slight phosphate problem was at .25 but started using a sponge and it has come down. Base phosphate problem on my tap water. I tested the RO water right when i opened it. I have read that the water is too pure so a ph reading will be innaccurate. But I would like a second opinion on this. I am going reef so I plan on trying to catch the yellow tail wrasse and trade him for something. Sorry i got a little off topic there. I enjoy being formal!! :)

Markus
You still did not answer my question about how you measure pH. Right now that is the most important question.

RO/DI water is pH 7.0.
 

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Nyles said:
My PH is high from my water after RO/DI

I hold my water in a bin (44 gal) for 5 days circulated so it will naturally come down to 8.2, I use it for water changes and top off.

This works perfectly, you could fight with ph down or baking soda but letting it sit will be most natural way.
There is no question that pH of distilled water drops over time. The CO2 from the air mixes with the water forming carbonic acid which lowers the pH.

But perfectly neutral distilled (or RO/DI) water is 7.0 at the highest, and drops from there as the CO2 approaches equilibrium, (which can happen quickly). If the pH measurement is higher than 7.0 to start, then most likely the error is in the measurement.
 

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Discussion Starter #9
Sorry I measured the RO water with a nutrafin test kit. Just 4 drops out of one bottle and match colour immediatly. Drsyme your saying that it must be at 7.0. Which makes sense because there is nothing in the water to make it basic nor acidic.
 

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Nyles said:
My PH is high from my water after RO/DI

I hold my water in a bin (44 gal) for 5 days circulated so it will naturally come down to 8.2, I use it for water changes and top off.

This works perfectly, you could fight with ph down or baking soda but letting it sit will be most natural way.
I stand to correct myself as well, mine is low and I hold my water and it naturally comes up to 8.0, or there about.... been a while since I tested make up water. I only remember this because when I first started I would add vinegar to get it up to 8.2 fast, now I just hold in a tub for a few days. I prefer this anyways since I don't have to add other things and take a chance of impurities getting in my water.
 

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Discussion Starter #12
Thanks Brent. Yes I cant wait to get that hood. The shimmer at the lfs is amazing. Not to mention the options it opens up for corals and such. So Nyles you are saying that you dont add anything to your top up water. Just let it sit in open air for a few days.
 

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Markus said:
Sorry I measured the RO water with a nutrafin test kit. Just 4 drops out of one bottle and match colour immediatly. Drsyme your saying that it must be at 7.0. Which makes sense because there is nothing in the water to make it basic nor acidic.
Yes so if it is measuring 9.0 the kit is incorrect. These kits are imprecise and are designed only to measure within a narrow range. Plus there can be problems with out of date reagents, and poor technique. Not to mention that matching colors can be very difficult and can vary depending on the type of lighting in the room.

Was it the high range pH kit or low range? You should use the high range, but the intended range of this test kit is outside the range of ro/di water.

To best determine pH throughout the day, the most accurately, get a pH meter and keep it well calibrated.
 

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Discussion Starter #14
Thank you Drsyme. I just purchased that test kit, but I guess I'll have to get more accurate. I was using the high range. I shouldn't really need to be stressin' about that anyways correct. It's what goes in the tank that counts.
 

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Don't add anything to your RO/DI water.

If you're using it for top off...add nothing.

if you're using it for water changes...add your salt mix

if you're using it for Kalkwasser...add kalk.

But while it's sitting in the tub, waiting for it's purpose...add nothing.

Hoping the advice so far about your test kits being faulty/inaccurate are right. If not, the problem MIGHT be the fact that you were adding vinegar and whatever else. The equipment or container it's in *might* have absorbed some of that...and it leeching it back out in new RO/DI water.

As stated, RO/DI water SHOULD be somewhere around 7.0 (not much variance).

btw...Welcome to TRT!!!! And happy about your first thread. (make sure it's not your last! ;) )

If the answers thus far havne't helped...please feel free to ask more questions!!
 

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Discussion Starter #16
An excellent response skeety, and everyone else. I fished what i wished :)

Markus
 

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drsyme said:
There is no question that pH of distilled water drops over time. The CO2 from the air mixes with the water forming carbonic acid which lowers the pH.

But perfectly neutral distilled (or RO/DI) water is 7.0 at the highest, and drops from there as the CO2 approaches equilibrium, (which can happen quickly). If the pH measurement is higher than 7.0 to start, then most likely the error is in the measurement.
Definitely true for distilled water when distilled with glass or other inert distilation column materials, HOWEVER...


...when we use RO/DI to make our purified water, we first remove all the large particulates, then process the water with carbon to remove some of the organics and adsorb some of the junk, then we process the water by squeezing it through the very small holes in the TFC, etc membrane of the RO filiter. The RO membrane works as a molecular sieve, keeping back all the large or ionized ions with large electron/ionic clouds, but still allowing a few of the very smallest ions through. The higher the rejection rate of the membrane, the more pure the water will be. The remaining materials (some phosphate, silicon, a few other ions as well) that make it through the RO membrane must be removed via the use of the deionizing resins in the DI section of the water purificaition unit. These resins work by exchanging either protons or hydrxyl ions for the cation/anion in question, and these exchanged ions will have an effect on the pH, either up (more basic) when anions are exchanged, or down (more acidic) when cations are exchanged. Although this effect is measurable, the STRENGTH of this ionization is very weak (basically (no pun in ten did ;) ), it is the ionization of a very small amount of the water, 10^-7= 0.00000001 ionic concentration + 0.0000000001% or so depending on the actual pH), and will have little effect on out final pH of the ASW solution with respect to the strength of the carbonate/bicarbonate buffer system in seawater when final dilution is met. As has already been pointed out, dissolved CO2 has a much more profound effect on the actual pH of the water.


Although Jack's comment on real distilled water USP is true, we unfortunately must make do with the RO filter results and the effects, although insignificant, that the deionization column will have on the final product when polshing out the remaining ionic load.


A note from your friendly local chemistry geek splitting hairs in uper BFE.


:D

HTH
 

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tdwyatt said:
Definitely true for distilled water when distilled with glass or other inert distilation column materials, HOWEVER...


...when we use RO/DI to make our purified water, we first remove all the large particulates, then process the water with carbon to remove some of the organics and adsorb some of the junk, then we process the water by squeezing it through the very small holes in the TFC, etc membrane of the RO filiter. The RO membrane works as a molecular sieve, keeping back all the large or ionized ions with large electron/ionic clouds, but still allowing a few of the very smallest ions through. The higher the rejection rate of the membrane, the more pure the water will be. The remaining materials (some phosphate, silicon, a few other ions as well) that make it through the RO membrane must be removed via the use of the deionizing resins in the DI section of the water purificaition unit. These resins work by exchanging either protons or hydrxyl ions for the cation/anion in question, and these exchanged ions will have an effect on the pH, either up (more basic) when anions are exchanged, or down (more acidic) when cations are exchanged. Although this effect is measurable, the STRENGTH of this ionization is very weak (basically (no pun in ten did ;) ), it is the ionization of a very small amount of the water, 10^-7= 0.00000001 ionic concentration + 0.0000000001% or so depending on the actual pH), and will have little effect on out final pH of the ASW solution with respect to the strength of the carbonate/bicarbonate buffer system in seawater when final dilution is met. As has already been pointed out, dissolved CO2 has a much more profound effect on the actual pH of the water.


Although Jack's comment on real distilled water USP is true, we unfortunately must make do with the RO filter results and the effects, although insignificant, that the deionization column will have on the final product when polshing out the remaining ionic load.


A note from your friendly local chemistry geek splitting hairs in uper BFE.


:D

HTH
So what is the pH of RO/DI before we make it ASW?
 

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Discussion Starter #20
Thanks reefboy, I think I can get used to this kind of advice!
 
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