Stable PH or Alk .... Can't have both

Lazylivin

Premium Member
As we all know dosing Soda Ash raises PH. Additionally when the lights come on PH increases. Many dose their alk solution when lights are out to flatten the PH rise and falls. However that makes for a larger Alk swing by not dosing during the entire light cycle. So my question is which is better, flatten PH swings or Alk swings. I can dose on an oscillation and remove the alk swing all together but the PH swing will be higher or I can minimize PH swing by dosing Alk on a schedule opposite to the lights. Which is better for the corals? I realize both are acceptable and can be successful either way I am looking more for a discussion on this topic.
 
I check Calcium & Alkalinity stability first. Using a Kalkwasser/RO mixture in my ATO, I have yet to read anything lower than 8.1 or higher than 8.4 in the tank (4 years of testing).
 
Ph and ALK are linked and should be tested in the morning only as they can change from tank activity. The morning reading will be the most accurate. Also in newier tank they tend to take time to balace out as the tank matures say at least 1 year maybe longer.
So if your tank is newier and your morning reading is in the safe range then i would not mess with it , let it do its thing.
 
Ph and ALK are linked and should be tested in the morning only as they can change from tank activity. The morning reading will be the most accurate. Also in newier tank they tend to take time to balace out as the tank matures say at least 1 year maybe longer.
So if your tank is newier and your morning reading is in the safe range then i would not mess with it , let it do its thing.

I understand pH will change due to various factors during the day, and alk will go down some, but what makes you think testing pH and alk in the morning is any more accurate than testing any other time of the day? Testing accuracy is in the ability of the tester and equipment, not the time of day. Getting a repeatable and representative number means you should do the tests at about the same time of day every time you test, but morning, afternoon or middle of the night shouldn't make any difference.

I agree that tanks do take 6-12 months to fully mature and settle into a smoother pattern. But pH and alk should be fairly stable within a month or two after the ammonia cycle is done. pH should be fairly stable within a range, say 8.0 and 8.2 over a 24 hour period. And it should stay in that range for long stretches of time (weeks or months) if nothing dramatic happens to the tank. Alk and cal should be stable and shouldn't need much to keep them consistant until you start to introduce lps and sps corals. Sure, most of the critters we keep use some cal & alk (snails, shrimp, crabs, fish...), but they don't use that much. Get to the point where sps & lps are growing fast and are of bigger size and you will need to dose much more alk & cal (and mag) to keep things stable.

To the OP: Don't sweat swings of 0.2 or 0.3 in pH over the course of a day. Just don't let it track or trend away from that range over time. Keeping alk stable isn't that critical either (as long as you stay in a safe range). It's more important if you have lps & sps corals. And then you can have some drift over time, but avoid sudden changes and try to keep in a range between 7-9 dKh. Good luck.
 
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Keep the alk stable and do not worry about the ph swings. Your corals are far more stressed by fluctuating alk than they are with ph.
 
^Agreed

Dose alk supplements based on alk tests. PH will generally fall in line but dosing to maintain a certain PH will usually lead to troubles with alkalinity and calcium.

Testing at the same time every day is wise. The actual time of day has no impact on the accuracy of the test.
 
I agree with Jerpa above. pH is also a function of Carbon Dioxide level in the atmosphere, and it will trend downward in a closed room. Using it to control the amount of dosing Alk can be problematic. It's much safer to simply do an Alk titration to adjust your Alk dosing.
 
In this hobby were extreme patience is a minimum prerequisite lets agree that 6 - 12 months in no way represents a mature reef tank.
 
In this hobby were extreme patience is a minimum prerequisite lets agree that 6 - 12 months in no way represents a mature reef tank.

Why do you think that it would take more than 12 months to establish a tank? This seems somewhat absurd to me given that any bacterial cultures would have more than enough time to stabilize in far less than a year.

Please dont misunderstand my tone, I'm not confrontational I am just curious what data you have to support that assertion. From what I have seen most of the people on these forums would agree with you, but I have never seen anyone explain why.
 
I agree with Jerpa above. pH is also a function of Carbon Dioxide level in the atmosphere, and it will trend downward in a closed room. Using it to control the amount of dosing Alk can be problematic. It's much safer to simply do an Alk titration to adjust your Alk dosing.

The CO2 would trend upward, causing pH to trend downward, I think. Just to clarify. Night time pH drops typically because of there is less CO2 being used up via photosynthesis with lights on - which is why many like to run refugiums or algae scrubbers during night cycle. I find the french method of pH/alk stabalization is very intriguing... Anyone check out Jean's video? and the other examples he posted in his thread? Pretty amazing results...
 
Why do you think that it would take more than 12 months to establish a tank? This seems somewhat absurd to me given that any bacterial cultures would have more than enough time to stabilize in far less than a year.

Please dont misunderstand my tone, I'm not confrontational I am just curious what data you have to support that assertion. From what I have seen most of the people on these forums would agree with you, but I have never seen anyone explain why.

No worries. I would say "established" is the point where the intended life can be supported without too many problems. It would probably depend alot on what your keeping. I'm sure most reefers are going to be there in the first 6 - 12 months. (hopefully). Mature would be more thought of as a growth stage. I would think a mature SPS tank would be 2 - 5 years, were well established varieties of bacteria are functioning to give a well balanced system. A mature tank can withstand major parameter problems (temp, pH, salinity) if they occur with out massive losses as long as they are corrected in a reasonable timeframe. I think the room for error gets alot larger as the tank gets older. This is just what I've experienced in 20+ years of invertebrate husbandry. As far as Data goes, we'll we reefers just seem to make most of this up as we go anyways don't we.:wildone: Sorry to detract from the original post.
 
No worries. I would say "established" is the point where the intended life can be supported without too many problems. It would probably depend alot on what your keeping. I'm sure most reefers are going to be there in the first 6 - 12 months. (hopefully). Mature would be more thought of as a growth stage. I would think a mature SPS tank would be 2 - 5 years, were well established varieties of bacteria are functioning to give a well balanced system. A mature tank can withstand major parameter problems (temp, pH, salinity) if they occur with out massive losses as long as they are corrected in a reasonable timeframe. I think the room for error gets alot larger as the tank gets older. This is just what I've experienced in 20+ years of invertebrate husbandry. As far as Data goes, we'll we reefers just seem to make most of this up as we go anyways don't we.:wildone: Sorry to detract from the original post.

Hai Sensei !

Yes, I'd agree with you ... my current 500g display is almost 6 years old now and it didn't really do much until it was around 3 years old since which time the sps has gone beserk ... it grows out of the water ! Why it takes so long for things to mature and establish an equilibrium that is conducive to sps is a mystery to me, but I see with my eyes. :hmm5:
 
Why it takes so long for things to mature and establish an equilibrium that is conducive to sps is a mystery to me

Probably has a lot to do with establishing periphyton on the rocks. Plus, any change in lighting, flow, or - god forbid - flipping a rock over, will destroy a lot of the periphyton.
 
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