does buffer affect dkh level?

[capn_hylinur]

I've been adding buffer to my tank about once a week. I am going through about 15 gal of r/0 water a week to top up evaporation. The ph will drop from 8.30 to 8.00 if I do not do this.

Does buffer affect the dkh level at all?

Mike dkH level fluctuates between 8.2 and 10.2 which I know is acceptable. I just wondering if I should keep more track of it if I am adding buffer.

[Billybeau1]

pH buffers contain excessive borate which can, with regular use, raise alkalinity extremely high. They are not a good choice for maintaining pH.

Do you have a reef tank or fish only ?

[capn_hylinur]

reef tank-----.025 salinity, 1300 mag, pH 8.2. dkH 8-10 cal 450 temp 78.--79.5

Why won't my pH level hold steady--it moves from 8.2 to 7.8 and then I have to add the buffers?

[capn_hylinur]

I use kent dkH buffer to maintain alkalinity, and seachem mag and calcium powder to maintain those readings.
Seachem buffer to raise the pH

[Billybeau1]

CO2 is likely suppressing your pH. Have you done the aeration test in Randy's pH article ? This will tell you for sure.

Measure your pH. Take a few cups of water out of your tank and take it outside and aerate it for about an hour with an air stone. Then test pH again. If your pH rises, you have CO2 issues.

Also photosynthesis causes pH swings. Some people light their fuge on a reverse light cycle to help with this.

I would stop using the pH buffer. It will give you problems down the road.

Some people have had success dripping limewater at night only to help offset the swing caused by photosynthesis.

[bertoni]

pH buffers are just high-pH alkalinity supplements. Some contain a lot of borate, some don't. Which SeaChem product is being used? The Marine Buffer is for fish-only systems.

[Boomer]

The ph will drop from 8.30 to 8.00 if I do not do this.

Because most buffers are mostly baking soda. Baking soda will cause an immediate initial lower pH. After the water has circulated and has run through the system for awhile the CO2 from this buffer will "blow-off" and the pH will go back up.

I hope, as Jon mentioned, you are not using SeaChem Labs "Marine Buffer". If so stop, as it will cause lots of problems trying to keep proper Alk, Ca, Mg and Alk values in line with normal sup's.

[SJimmyH]

You need to realize that alkalinity and pH correspond.

Alkalinity is a measure of mostly borates and carbonates in the water. We all realize that carbonates are very important to have in the tank to provide corals and coralines materials to build skeletal formations, but what most books don't tell you is that these are also weak bases. That means they raise the pH when added.

Now, do NOT add more alkalinity to fix your low pH. Here is why.

If you have an alkalinity in the optimum band (7-12 dKH) you should be able to maintain your pH in the optimum band. If you cannot, this means you have something dropping your pH. This is highly suspicious of CO2. CO2 has a nasty property in that as it disolves and removes the Hydroxyl Ions in your tank (thereby lowering the pH) it also forms a carbonate ion (a weak base, a part of your alkalinity measurement)

Now, if you remember from high school chemistry, a weak base does not add a Hydroxyl ion for every molecule disolved in water. It forms an equilibrium. Some of the weak base forms Hydroxyl to effect pH while some of it stays in reserve (the basic concept of buffers and the "reserve" to resist a change in pH).

Because every CO2 molecule disolved that forms carbonic acid will suck up a Hydroxyl Ion (lowers pH) but the afterward formed carbonate may form a replacement Hydroxyl Ion... or it could stay in reserve (because it is a weak base) the over all effect is:

Ph goes down while alkalinity remains exactly the same. Pretty cool, huh... Luckily for us it does this. That makes identification of a CO2 problem pretty easy to identify. If you require a high alkalinity to maintain pH... OR... you can't maintain pH even with a high alkalinity, then CO2 is most likely your culprit.

I just got into a huge discussion on this on another board. Most everyone that chimed in disagreed with me. A guy had a pH of 7.8 with an alkalinity of 16 dkh. He just started kalkwasser to try to help out. He was told by my couterparts to stop the kalkwasser drip and do a large water change to lower alkalinity.

My thought was, if he has high CO2 in his home... this would cause pH to drop like a rock. So, I recommended keep the kalkwasser going and do small water changes to get the alkalinity back in the optimum band where I was thoroughly blasted by three individuals with decent reef experience as to how messed up I was.

Anyway, read the article by Randy and the follow-up links provided to get the gouge.

Raising your alkalinity any further (buffers) may lead you to precipitate out Calcium, Magnesium and Strontium... that wouldn't be what you want. Besides, after the precipitation... you would just end up near the same pH you started with (which is what you are seeing) if not lower.

[capn_hylinur]

Originally posted by Billybeau1
CO2 is likely suppressing your pH. Have you done the aeration test in Randy's pH article ? This will tell you for sure.

Measure your pH. Take a few cups of water out of your tank and take it outside and aerate it for about an hour with an air stone. Then test pH again. If your pH rises, you have CO2 issues.

Also photosynthesis causes pH swings. Some people light their fuge on a reverse light cycle to help with this.

I would stop using the pH buffer. It will give you problems down the road.

Some people have had success dripping limewater at night only to help offset the swing caused by photosynthesis.

I suspected a co2 problem three months ago but since then I have removed the sump from the cabinet and placed it in the basement, have added a refug(which the light is on reverse cycle)and increased the tank flow from about 8 times an hour to 20.
I removed all bioballs, foam etc from the sump and am using a micron filter bag.
In the tank itself I have three power heads--two agitating the surface.
I can't see where co2 is still an issue with the opportunity for air exchange that I have.
Any thoughts--appreciated as always

[SJimmyH]

Originally posted by capn_hylinur
I suspected a co2 problem three months ago but since then I have removed the sump from the cabinet and placed it in the basement, have added a refug(which the light is on reverse cycle)and increased the tank flow from about 8 times an hour to 20.
I removed all bioballs, foam etc from the sump and am using a micron filter bag.
In the tank itself I have three power heads--two agitating the surface.
I can't see where co2 is still an issue with the opportunity for air exchange that I have.
Any thoughts--appreciated as always

I personally have about 2000 ppm CO2 in my house just due to people and pets breathing and lack of adequate ventilation. As long as the water is exposed to that air, it will absorb excess CO2. (btw, normal CO2 outside is about 350 ppm)

[Boomer]

Nice little post Jimmy but you forgot one thing Even though the OH- ions for the kalk sucks up CO2 and raises the pH, it also increases Alk.

Ca(OH)2 ----> Ca++ + 2OH

2OH + 2 CO2 = 2 HCO3- alk

So adding kalk with a already high Alk will just make it even higher. Adding or removing CO2 by itself will have no impact on Alk but when it reacts with other things , like OH-, it will impact Alk.

[SJimmyH]

Originally posted by Boomer
Nice little post Jimmy but you forgot one thing Even though the OH- ions for the kalk sucks up CO2 and raises the pH, it also increases Alk.

Ca(OH)2 ----> Ca++ + 2OH

2OH + 2 CO2 = 2 HCO3- alk

So adding kalk with a already high Alk will just make it even higher. Adding or removing CO2 by itself will have no impact on Alk but when it reacts with other things , like OH-, it will impact Alk.

Yeah, thats why they blasted me... BUT he was already dripping when he posted and he had stated that his calcium and alkalinity did not raise (was prob precipitating excess) but that his pH went up to 8.1... I figured since he was already dripping and wasn't having an issue to just keep it going and start his water changes to get the alkalinity back down.

I guess its just a difference of opinion.

[capn_hylinur]

I been following Randy's guide for maintaining calcium and alkalinity levels for six months. I use kent calcium boost and seachem reef builder for calcium and alkalinity depending on the need. My pH has always been a problem with not been able to keep an 8.2 for more then a week.
I am not sure which buffer I am using--will have to check later when I am off work.
I understand completely what you guys are saying and I appreciate it
It is a new house, with air on , closed windows and three dogs(one's a big lab) I can see where co2 could be an issue.
It was at xmas---if we had a large number of people over the pH would drop rapidly in the tank.
So how do you address a co2 probllem when you can drip kalk?

[capn_hylinur]

I been following Randy's guide for maintaining calcium and alkalinity levels for six months. I use kent calcium boost and seachem reef builder for calcium and alkalinity depending on the need. My pH has always been a problem with not been able to keep an 8.2 for more then a week.
I am not sure which buffer I am using--will have to check later when I am off work.
I understand completely what you guys are saying and I appreciate it
It is a new house, with air on , closed windows and three dogs(one's a big lab) I can see where co2 could be an issue.
It was at xmas---if we had a large number of people over the pH would drop rapidly in the tank.
So how do you address a co2 probllem when you can drip kalk?

[SJimmyH]

http://www.reefcentral.com/forums/sh...readid=1148592

Funny you should ask... I just posted what I am doing in the above thread.

[capn_hylinur]

Originally posted by SJimmyH
http://www.reefcentral.com/forums/sh...readid=1148592

Funny you should ask... I just posted what I am doing in the above thread.

Thanks I just read through the post----I think my problem is in the poorly vented small room where the 110 gal is. It is already covered with a wooden canopy. The coral life lighting was causing a major heat issue before so we added to external fans plus the three fans in the canopy. The evaporation is still 5 gal every other day. But I can see co2 building up in that room very quickly.
I am going to try to hook a fan up at the door way to try and recirculate the air better and see if that makes a difference in the pH-----like I mentioned it did at xmas.
I was just under the assumption that surface exchange would not be as problematic with a 30 gal sump and 30 gal fuge in the basement
Thanks for all the help--everyone
Scott

[SJimmyH]

Originally posted by capn_hylinur
Thanks I just read through the post----I think my problem is in the poorly vented small room where the 110 gal is. It is already covered with a wooden canopy. The coral life lighting was causing a major heat issue before so we added to external fans plus the three fans in the canopy. The evaporation is still 5 gal every other day. But I can see co2 building up in that room very quickly.
I am going to try to hook a fan up at the door way to try and recirculate the air better and see if that makes a difference in the pH-----like I mentioned it did at xmas.
I was just under the assumption that surface exchange would not be as problematic with a 30 gal sump and 30 gal fuge in the basement
Thanks for all the help--everyone
Scott

Good Luck! Keep in mind though... if the home is retaining CO2, then ventilating with air from the home won't do you much good. You will need fresh air that you know has low CO2 in it.