Buffering Top Off Water?

[CastAway]

As a newbie, I'm sure there are gaps, big ones, in my understanding and methods in this hobby, and I might have found one today - "buffering".

Today at our local club meeting I learned that several members use an additive in their RO/DI store to bring the pH up prior to using it to top off. I do not, have not, and didn't know to buffer my top off water.

So my question is, does this have to be done? Should it be done?

I average 2 gal per day evaporative loss, and my pH is consistently low, which I've always attributed to the CO2 and my calcium reactor use. I've been contemplating limewater to address this. Now, I'm wondering if it might improve my chronically low pH by buffering my top off water. What's the difference between limewater and this buffering compound? Are they one and the same?

 

[Downbeach]

What are your pH, Ca, Mg and Alk readings? What are you using to measure your pH? Is your Ca reactor adjusted properly? Is it a dual chamber?
I would suggest using kalk to help elevate your pH, over a buffer. A buffer is just another form of an alkalinity supplement, that will raise your alkalinity, but do little to take up the excess CO2 which is what's causing the low pH. Adding kalk can raise the pH by taking up excess carbon dioxide and adding alkalinity, all without raising alkalinity relative to calcium, since its a good balance of both alk and Ca.

 

[GainesvilleReef]

Kalk will help your pH. But it's effect is based on the rate that you add it. CO2 will always be replaced from the environment. So you need a significant demand for Alk and Ca to be replaced to be effective. Right now that demand is being met by your Ca reactor. So while running the Ca reactor Kalk will not be very effective for you. What I would suggest is stop running the Ca reactor. Determine the Alk and Ca consumption in the tank as it declines and replace that with kalk. Depending on the consumption of your tank Kalk my or may not meet the entire needs. If it does not, start the Ca reactor again to supply the demand over what the max that kalk can supply.
The Alk and Ca that Kalk can supply is limited by the evaporation in the tank. With the evaporation rate of you tank kalk will probably meet all your needs. I would also recommend dosing a saturated kalk solution with a dosing pump instead of the ATO. Dripping it in will eliminate the pH spikes that you can get with the ATO. Remember I said it is the rate that it is added that effects pH. Too quickly will raise the pH significantly. The rate it is dosed can also be a limiting factor. But also kalk in a saturated solution is a very precise mixture. Randy says it is even used as a high pH standard. With that and a dosing pump you can really dial in your levels. Kalk is easier and way less complicated than a Ca reactor. In my opinion every tank should start off with kalk first, then 2-part and last a Ca reactor.

One thing to notice about Kalk, 2-part and Ca Reactors. The all add Ca and Alk in a balanced method. When you add buffer to correct pH you increase your alk and create imbalance and overdosing problems. And on top of that it's effect is only temporary because just like kalk it is really the rate that the buffer is added that matters. The CO2 will soon return.

I started with 2-part and switched to kalk because I have basement tanks and CO2 issues.

If you have not read this yet. This is one of Randy's best.

http://reefkeeping.com/issues/2005-01/rhf/index.htm

 

[CastAway]

My plan was to get a kalk stirrer, a pH controller, and dose to a set pH. This was to counter the effect my Ca reactor was having on pH. My pH is 7.8-8.0. Not problematic, just not where I want it. I think my SPS would do better at 8.3 or so.

But, now I hear about this buffering of RO/DI, and was curios if doing this might lessen the need to address the consistently low pH by buying several pieces of expensive equipment.

Thanks for all the input. Frankly, I'll have to absorb it.

 

[Downbeach]

Can you run an air line from your skimmer to an outside air source? Have you tried running the effluent from the Ca reactor through the skimmer, which might help blow off some of the CO2? BTW, I successfully ran a 180 predominantly SPS mixed reef for many years at those pH numbers.

 

[GainesvilleReef]

My plan was to get a kalk stirrer, a pH controller, and dose to a set pH. This was to counter the effect my Ca reactor was having on pH. My pH is 7.8-8.0. Not problematic, just not where I want it. I think my SPS would do better at 8.3 or so.

But, now I hear about this buffering of RO/DI, and was curios if doing this might lessen the need to address the consistently low pH by buying several pieces of expensive equipment.

Thanks for all the input. Frankly, I'll have to absorb it.

If you are happy with the tank leave it all alone. If the low pH is that big of a problem Ca reactors would never be used. If that is not what you want to do I would scrap the reactor and switch to kalk. It is so cheap and easy to do.

 

[hig789]

Assuming you don't run a lid on your tank I would just open the windows if possible and let some fresh air into the room and increase the surface agitation. Or like mentioned above run the air line for the skimmer outside and let it pull in fresh air.

Mine always ran about 7.8 even when running a skimmer(but I was running a lid on my tank too). I removed the lid and got some fresh air into the house and after a few days my ph has been staying at 8.2.

Like above everyone told me that a buffer is just a temp fix. You need to get to the root of the problem. From the research I have done its possibly a co2 build up.

I will probably still add kalk to my top off water when my ATO container gets finished. This will also help control the ph swing at night.

Here's Randy's article on the subject.
http://reefkeeping.com/issues/2004-09/rhf/index.htm

 

[Randy Holmes-Farley Verified Community Expert]

As a newbie, I'm sure there are gaps, big ones, in my understanding and methods in this hobby, and I might have found one today - "buffering".

Today at our local club meeting I learned that several members use an additive in their RO/DI store to bring the pH up prior to using it to top off. I do not, have not, and didn't know to buffer my top off water.

So my question is, does this have to be done? Should it be done?

I average 2 gal per day evaporative loss, and my pH is consistently low, which I've always attributed to the CO2 and my calcium reactor use. I've been contemplating lit lower the pH of seawater.mewater to address this. Now, I'm wondering if it might improve my chronically low pH by buffering my top off water. What's the difference between limewater and this buffering compound? Are they one and the same?

It is a fine way to boost the alkalinity of the aquarium. It is not necessary or even desirable if the alkalinity is not closely monitored.

The apparent pH of RO/DI is no concern. Adding pH 7 RO/DI water does not lower the pH of seawater. It might even raise it.

 

[CastAway]

Excellent. This seems to answer definitively the idea of buffering my RO/DI. I will not be doing this, because not doing so is apparently not decreasing my pH, and, my alk is where I want it via my Ca reactor.

Thanks everyone!

So I'm assuming that my club mates are buffering their RO/DI for the sake of alkalinity, not pH, even if unknowingly.

BTW, I do not run my Ca reactor effluent to my skimmer for two reasons: one, I'd have no easy means to visualize the flow rate, and two, I think there's some potential that doing so might cause Ca to fall out due to rapid pH change - 6.6 to 8.

 

[Randy Holmes-Farley Verified Community Expert]

So I'm assuming that my club mates are buffering their RO/DI for the sake of alkalinity, not pH, even if unknowingly.
.

Some people mistakenly think that adding top off water at pH 7 must lower the pH of the aquarium which is at about 8.2. They are wrong, but that may be why they do it.