Alkalinity decline without coral

keithIHS

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My 110 gal tank is a few months old, and pH was around 7.6 and alkalinity around 5-6 (Tropic Marin Pro). I'm trying to raise my alkalinity and pH by dosing baking soda (in RODI). I've gotten alkalinity up to about 8.5 (pH is about 8). Alk goes up by about 0.5 dKh after I dose, but then over a day or two it drops back down. Everything I've read about alkalinity is the context of replacing what corals and coraline consume, so I don't know what to expect when there is none. The only inhabitants are two small clowns. There's a little bit of very pale red macroalgae in the refugium, but no other algae and no coralline. What might be causing the alkalinity to drop?
 
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blasterman

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Yep :)

Sorry, I just answer this a lot.

Alk is consumed by many biological processes in a tank other than coral. Younger tanks can consume alk at an astonishing rate as their biology gets established. I've had young tanks drop 2 points of dKH a day for months as bacteria beds get established. No corals. Get a diatom bloom? Watch your alk plummet as the carbon is used as building blocks.

Calcium and magnesium however only get consumed by coral. The only time alk and calcium get consumed in a defined ratio is when you have a lot of healthy growing SPS.

Unfortunately the two part industry doesn't tell you this because they make a lot of money selling two part jugs of mostly water to newbs who aren't clear on the science. Repeat: unless you have lots of rapidly growing SPS you don't need to dose calcium.

Just keep the alk up with grocery store baking soda. I wouldn't bother checking more than once a week since you don't have coral. At some point the alk consumption will level off and that's usually when long term tank stability starts.
 
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keithIHS

keithIHS

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Thank you. That makes a lot of sense. I wonder also if I'm getting some precipitation that I just don't notice yet.
I should have mentioned that the 120 lb of rock has been cycling since last April and the 55 lb of sand since October with grocery shrimp bits, fish bits, and ammonium chloride. The Clowns went into the tank mid November. So I thought the rock and sand would be well established by now. I'll reset my definition of slow...again. Also, I bought two varieties of red macroalgae, Pom Pom and Red Ogo, for the sump and killed one and the other is a pale sad remnant of the original. Algae Barn speculated that my fuge light was too strong and pH and alk too low, so trying to get alk and pH back up for the algae. Actually, they said alk, but I suspect it was a typo and they meant pH. So I'm trying to get alk up to 9 because that's where I want it long term and this will get my pH up, a little anyway; and I want to see what my normal uncorrected pH will be with alk 9 so I can see if I need to run an outside air-line or CO2 scrubber or maybe dose with soda ash. I'm getting 20 lbs of GARF Grunge on Friday, along with some Chaeto, and I want to make sure I don't kill it, too. Lastly, I'm trying to practice stability, so to speak, in preparation for corals once it's appropriate.
Thanks again for the help.
 

Randy Holmes-Farley

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Thank you. That makes a lot of sense. I wonder also if I'm getting some precipitation that I just don't notice yet.
I should have mentioned that the 120 lb of rock has been cycling since last April and the 55 lb of sand since October with grocery shrimp bits, fish bits, and ammonium chloride. The Clowns went into the tank mid November. So I thought the rock and sand would be well established by now. I'll reset my definition of slow...again. Also, I bought two varieties of red macroalgae, Pom Pom and Red Ogo, for the sump and killed one and the other is a pale sad remnant of the original. Algae Barn speculated that my fuge light was too strong and pH and alk too low, so trying to get alk and pH back up for the algae. Actually, they said alk, but I suspect it was a typo and they meant pH. So I'm trying to get alk up to 9 because that's where I want it long term and this will get my pH up, a little anyway; and I want to see what my normal uncorrected pH will be with alk 9 so I can see if I need to run an outside air-line or CO2 scrubber or maybe dose with soda ash. I'm getting 20 lbs of GARF Grunge on Friday, along with some Chaeto, and I want to make sure I don't kill it, too. Lastly, I'm trying to practice stability, so to speak, in preparation for corals once it's appropriate.
Thanks again for the help.

I expect that precipitation of calcium carbonate happens in all tanks (the evidence is often obvious on heaters and pump impellers) and it is especially prone to happen in tanks with new calcium carbonate sand that is providing lots of surface area to seed precipitation.
 

living_tribunal

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My 110 gal tank is a few months old, and pH was around 7.6 and alkalinity around 5-6 (Tropic Marin Pro). I'm trying to raise my alkalinity and pH by dosing baking soda (in RODI). I've gotten alkalinity up to about 8.5 (pH is about 8). Alk goes up by about 0.5 dKh after I dose, but then over a day or two it drops back down. Everything I've read about alkalinity is the context of replacing what corals and coraline consume, so I don't know what to expect when there is none. The only inhabitants are two small clowns. There's a little bit of very pale red macroalgae in the refugium, but no other algae and no coralline. What might be causing the alkalinity to drop?
Have you had any changes in nitrate levels?
 
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keithIHS

keithIHS

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Thanks, @Randy Holmes-Farley. BTW, somewhat related, where can I find a calculator for Ω and do you know where I can find your Reefkeeping articles, e.g. Reef Aquarium Water Parameters, http://www.reefkeeping.com/issues/2004-05/rhf/index.php, where the symbols are all present? Maybe the problem is my browser, but in a number of your articles there are missing symbols. Thanks.
@living_tribunal I haven't been tracking Nitrate. I know I need to, or at least will need to once I get closer to getting corals. I tested it mid Dec with the Nyos kit and got 12-25 ppm. Testing just now I get 5-12.
 

Cheeze

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Any update on your Alk level? Has it stabilized, and what have you done?

The Alkalinity in my tank has also dropped...it's been cycled a couple of months now, so no corals yet, and I went through a diatom phase but it seems to have disappeared. But now my water has been "cloudy" for a few days, wonder if my Alk dropped because of another pending algae bloom.
 
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keithIHS

keithIHS

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I think the algae in my refugium is consuming the alk. I've been growing GHA, sort of by accident, in the refugium because everyone seems to be out of chaeto. So I just let the GHA grow. When I have lots of GHA, the alk seems to drop about 0.5/wk. I harvested most of the GHA and the alk drop was less. Also, if my alk is above 9, it drops much faster. If I let it get down to 8.5, it doesn't drop nearly as fast. I haven't been rigorous about testing all this: I've been changing some other things like fuge light schedule and intensity, salt brand, amount of food into the tank, adding fish, etc., but I really think it's the algae consuming the alk and the consumption rate increases with increasing alk. No precipitation by the way, and calcium is unchanged.
I just harvested GHA again and added sea lettuce and gracilaria to the sump, so it will be interesting to see what happens...
 
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keithIHS

keithIHS

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FYI, my rock has been cycling for a year, the sand for about 6 months. First 2 fish went in to the aquarium 5 months ago. I'm now up to 5 fish, a shrimp, and a half dozen small hermits and a half dozen small snails...and GHA, sea lettuce, and gracilaria in the sump :) No light on the aquarium yet and no coral yet :(
 

arking_mark

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I think the algae in my refugium is consuming the alk. I've been growing GHA, sort of by accident, in the refugium because everyone seems to be out of chaeto. So I just let the GHA grow. When I have lots of GHA, the alk seems to drop about 0.5/wk. I harvested most of the GHA and the alk drop was less. Also, if my alk is above 9, it drops much faster. If I let it get down to 8.5, it doesn't drop nearly as fast. I haven't been rigorous about testing all this: I've been changing some other things like fuge light schedule and intensity, salt brand, amount of food into the tank, adding fish, etc., but I really think it's the algae consuming the alk and the consumption rate increases with increasing alk. No precipitation by the way, and calcium is unchanged.
I just harvested GHA again and added sea lettuce and gracilaria to the sump, so it will be interesting to see what happens...
I'd say your GHA is consuming CO2 and raising your pH. Higher pH increases Alk consumption biological and abiotic precipitation.
 
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keithIHS

keithIHS

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My original post was due to alk drop with almost no algae in the fuge. Blasterman above says "Alk is consumed by many biological processes" so it's probably GHA, diatoms, bacteria, and who knows what else.
I had hoped that algae would raise my pH, but my Apex pH probe has been telling me ~8 with a daily swing +/- 0.05 for months. One thing that was cool was we went away for a few days in March and the pH rose to 8.1 with almost 0 daily swing. This tells me the pH is being driven, at least partly, by CO2 in the air in our home. When we're home, there's more CO2, lowering the pH. I'm sure the GHA is affecting the pH because the daily swing in pH changed when I changed the fuge light from 24 hrs/day to 12 hrs, and consumption of CO2 by GHA is certainly having an effect on pH. Maybe pH would be even lower if I didn't have GHA. I need to stop tweaking multiple things at once (too much fun), and see if I can get a better idea of correlations of parameters.
 

Randy Holmes-Farley

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My original post was due to alk drop with almost no algae in the fuge. Blasterman above says "Alk is consumed by many biological processes" so it's probably GHA, diatoms, bacteria, and who knows what else.

Either his comments, or your interpretation of them, are seemingly not correct. We do know what depletes alkalinity, and the only thing that is significant in a reef tank (aside from calcification) is conversion of ammonia to nitrate. That depletes alk. A rise in nitrate by 50 ppm will deplete 4.5 dKH or alk.

There is not a big list of other "processes" that deplete alkalinity. No other normal processes by algae or bacteria or anything else deplete alkalinty.

Bear ion mind that many organisms form calcium carbonate and deplete alkalinity. Worms (some types), snails, bivalves, etc. can deplete alkalinity. Abiotic precipitation of calcium carbonate is also often significant and can be the major sink in a new tank.
 

Cheeze

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Sorry for hijacking the convo!

My alkalinity has dropped significantly to about 4.6 (shame on me for not testing it for a couple of weeks), but both my Ammonia and Nitrate is 0. I have just 3 hermits and 3 snails in a 38 gallon tank, no corals yet, 1 fish. Obviously my tank isn't stable yet, been just under 3 months since it cycled, but could anything else be attributed to this drop?

I do weekly water changes with RODI and have been using RedSea blue bucket.
 

Randy Holmes-Farley

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Sorry for hijacking the convo!

My alkalinity has dropped significantly to about 4.6 (shame on me for not testing it for a couple of weeks), but both my Ammonia and Nitrate is 0. I have just 3 hermits and 3 snails in a 38 gallon tank, no corals yet, 1 fish. Obviously my tank isn't stable yet, been just under 3 months since it cycled, but could anything else be attributed to this drop?

I do weekly water changes with RODI and have been using RedSea blue bucket.

It is likely mostly precipitation of calcium carbonate. It happens in all tanks, and more so in newer ones.
 
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keithIHS

keithIHS

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@Cheeze no shame, at least not to me. I didn't know it would drop either. The vast majority of discussion on alk drop is in the context of coral. We just missed this topic because it was overwhelmed by coral discussions. When my alk was first dropping I had an insignificant amount of algae and no inverts, at least none I'm aware of! It must be the conversion of ammonia to nitrate as @Randy Holmes-Farley said. My nitrate is now also near 0 (due to the algae?) My calcium is rock steady and I haven't seen any precipitate. Thanks Randy for the info.
 
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Randy Holmes-Farley

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Thanks Randy...do you suggest I dose soda ash or baking soda to bring it up, or just stick with water changes and wait until it (perhaps) stabilizes back up?

If you want a pH boost, use sodium carbonate/baked baking soda/soda ash.

If you do not want a pH boost, use sodium bicarbonate/baking soda.

If you do not know your pH, just pick one at random. :)
 
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keithIHS

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@Cheeze what's your pH? The pH boost will be temporary. If you dose it continuously you will get a continuous pH boost, but I dont recall how much of a boost. This is what I'm going to try next: daily dosing of a small amount of sodium carbonate. I have a Neptune DOS so might try dosing tiny amounts more frequently than daily. My pH hit 7.8 yesterday. Need to 2x check pH calibration and if in spec then I've got a problem I need to solve before I get corals. Also planning to run an air line to my attic to feed my skimmer.
 

Miller535

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ime, most of the time in newer tanks especially tanks without corals, the alk is precipitating straight into the sand. i had this happen in a fowlr tank that I started with dry sand. Turned the whole sand bed into large clumps of sand, started first underneath and around the rocks, then traveled out. The Fowlr tanks I started before that with "live sand" did not do that.
 
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