bigcheese007
New member
Has anyone had luck with purple up. I have read that it can cause ph drops. Is it worth the risk or is there any better products?
purple up?
- Thread starter bigcheese007
- Start date
I don't think that product is a good thing to dose. There are a lot of threads on Purple Up. For coralline algae growth, the first steps would be to make sure that calcium and alkalinity are okay, and work from there. High phosphate might cause a problem in some tanks, but calcium and alkalinity are the basics. Magnesium is worth checking from time to time since it affects the consumption of calcium and alkalinity.
Jasonanatal
New member
I personally believe that Purple Up is not necessary. Corralline Algae will come in due time within every aquarium as long as your water parameters are where they should be. Spend the money on some Corals or Fish. 
MCsaxmaster
New member
One of a long line of products that is mostly powder-fine aragonite in water. Aragonite does not disolve significantly at seawater pH (hence coral reefs can exist and do not dissolve as quickly as they are formed). It is completely worthless as far as I'm concerned.
cj
cj
Sugar, where did you hear that, that is a new one to me. I think you have been mislead. It contains 10 micro aragonite and dissolved Calcium Chloride.
The real issue with PU is that that 10 mico aragonite just sits on the bottom and then if you hit the right Omeg value, for pH, Alk and Ca++, it goes into solution. It has happen to many, with the Alk and Ca++ going through the roof.
There are lots of threads on forums where the tank is fine on all parameters and additives used then>>> POOF. I ask them are they/were they using PU and the answer is yes. And when they change the water, siphon the sand top and stop using the PU the issue goes away. Some swear by it, that it is the greatest thing since apple-pie but I'n not a fan by a long shot
The real issue with PU is that that 10 mico aragonite just sits on the bottom and then if you hit the right Omeg value, for pH, Alk and Ca++, it goes into solution. It has happen to many, with the Alk and Ca++ going through the roof.
There are lots of threads on forums where the tank is fine on all parameters and additives used then>>> POOF. I ask them are they/were they using PU and the answer is yes. And when they change the water, siphon the sand top and stop using the PU the issue goes away. Some swear by it, that it is the greatest thing since apple-pie but I'n not a fan by a long shot
MCsaxmaster
New member
If the water chemistry in your aquarium is such that the powdered aragonite will dissolve, your corals are already dissolving. If the chemistry is such that your corals are growing, this aragonite won't dissolve. It will add some calcium because it has CaCl2 in it, but it is a waste of money as far as I'm concerned. You can get CaCl2 for much cheaper, and without a bunch of powder-fine aragonite that won't dissolve anyway.
Not if the stuff is in the sand bed and the pH drops Chris. The smaller the grains size, angularity and sharp edges the more soluble it is.
There are lots of threads on forums where the tank is fine on all parameters and **NO additives used *and then>>> POOF one day , where PU was used, a week , 2 weeks before.
Those high ALk and Ca++ Chris came form some where
However, in Alk tests many of those particles will dissolve on titration due to your low pH end point given false Alk readings and the same may be said for Ca++. But I do not think this is always the issue. I never advise to use PU for thes reasons
What is your comment ?
Calcium Carbonate as a Supplement
http://www.advancedaquarist.com/issues/july2002/chem.htm
There are lots of threads on forums where the tank is fine on all parameters and **NO additives used *and then>>> POOF one day , where PU was used, a week , 2 weeks before.
Those high ALk and Ca++ Chris came form some where
However, in Alk tests many of those particles will dissolve on titration due to your low pH end point given false Alk readings and the same may be said for Ca++. But I do not think this is always the issue. I never advise to use PU for thes reasons
What is your comment ?
Calcium Carbonate as a Supplement
http://www.advancedaquarist.com/issues/july2002/chem.htm
MCsaxmaster
New member
Boomer,
Agreed, if the stuff makes it down into a sandbed or other place with a locally low pH it can dissolve, but to get any appreciable dissolution at all the pH has to drop pretty low (say around 7 or lower). That is unlikely in most tanks, even with a heavy organic load. Eventually this stuff can and will dissolve in such a situation (as will any other aragonite), but the rate is so low as to be essentially inconsequential in the context of an aquarium where calcium and alkalinity are in fairly high demand (even a low demand in a tank is very high demand relative to how slow this will dissolve). Even so, the concentration of calcium and alkalinity will tend to drop down to much lower than NSW levels over time since the pH of most of the tank will be much too high to get net dissolution. The only reason that the surface ocean in the tropics is able to maintain substantially supersaturated levels of aragonite over long time scales is that much of the ocean (lower than a few hundred meters in the Pacific, or a couple kilometers in the Atlantic) is near or below saturation with respect to aragonite. The surface waters are fairly far from equilibrium and this state is maintained by larger expanses of the ocean being at or below saturation due to high TCO2.
Yes, some of this will dissolve--there's no doubt about that. The amount is so small as to be negligible, however, especially at the pH (i.e., carbonate concentration) typical of a reef tank or of surface waters.
Yes, I suppose that if someone measures calcium or alkalinity while this is still suspended in the water, they likely would get a false high reading due to dissolution of the particles in cell.
Typically in my experience people are able to maintain appropriate or high calcium and alkalinity when using a product like this ONLY if they are also using tapwater. I used to maintain modest calcium and relatively higher alkalinity in a tank years ago just by using tapwater. The tapwater was pretty hard and had about 300 ppm calcium and 7 meq/l alkalinity (if I recall correctly) and demand for calcium and alkalinity in the tank was low. I'm sure that had I been dosing purple up or similar products the results would have been similar.
Chris
Agreed, if the stuff makes it down into a sandbed or other place with a locally low pH it can dissolve, but to get any appreciable dissolution at all the pH has to drop pretty low (say around 7 or lower). That is unlikely in most tanks, even with a heavy organic load. Eventually this stuff can and will dissolve in such a situation (as will any other aragonite), but the rate is so low as to be essentially inconsequential in the context of an aquarium where calcium and alkalinity are in fairly high demand (even a low demand in a tank is very high demand relative to how slow this will dissolve). Even so, the concentration of calcium and alkalinity will tend to drop down to much lower than NSW levels over time since the pH of most of the tank will be much too high to get net dissolution. The only reason that the surface ocean in the tropics is able to maintain substantially supersaturated levels of aragonite over long time scales is that much of the ocean (lower than a few hundred meters in the Pacific, or a couple kilometers in the Atlantic) is near or below saturation with respect to aragonite. The surface waters are fairly far from equilibrium and this state is maintained by larger expanses of the ocean being at or below saturation due to high TCO2.
Yes, some of this will dissolve--there's no doubt about that. The amount is so small as to be negligible, however, especially at the pH (i.e., carbonate concentration) typical of a reef tank or of surface waters.
Yes, I suppose that if someone measures calcium or alkalinity while this is still suspended in the water, they likely would get a false high reading due to dissolution of the particles in cell.
Typically in my experience people are able to maintain appropriate or high calcium and alkalinity when using a product like this ONLY if they are also using tapwater. I used to maintain modest calcium and relatively higher alkalinity in a tank years ago just by using tapwater. The tapwater was pretty hard and had about 300 ppm calcium and 7 meq/l alkalinity (if I recall correctly) and demand for calcium and alkalinity in the tank was low. I'm sure that had I been dosing purple up or similar products the results would have been similar.
Chris
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MCsaxmaster
New member
:thumbsup:
I forgot 
According to recent data the Alk of the ocean is rising due to dissolution of CaCO3 from a higher pCO2 but yup this has been over many, many years. And I forgot that many people that have had a deep sand bed for a few years and measured bed depth have seen a noticed loss in bed thickness.
According to recent data the Alk of the ocean is rising due to dissolution of CaCO3 from a higher pCO2 but yup this has been over many, many years. And I forgot that many people that have had a deep sand bed for a few years and measured bed depth have seen a noticed loss in bed thickness.
MCsaxmaster
New member
Rising ocean alkalinity is slow as the dickens. Oceanic pH will drop and stay low for quite a while before enough weathering/dissolution of carbonate minerals to return to saturation states like what we have today and the past.
People do sometimes notice that deep sand beds seem to get shallower over time, but I'm not convinced that this is due entirely to dissolution. In fact, I'm suspicious that very little of the sand bed is dissolving and the reduced depth is the result of compaction over time. I mean, the rates of dissolution in the kind of water chemistry we're talking about, even given a pretty significant reduction of pH in the porewater of the sand bed just isn't fast enough to make much difference.
People do sometimes notice that deep sand beds seem to get shallower over time, but I'm not convinced that this is due entirely to dissolution. In fact, I'm suspicious that very little of the sand bed is dissolving and the reduced depth is the result of compaction over time. I mean, the rates of dissolution in the kind of water chemistry we're talking about, even given a pretty significant reduction of pH in the porewater of the sand bed just isn't fast enough to make much difference.
Billybeau1
Premium Member
I like the compaction theory myself. Makes more sense.
Hi guys. :wavehand:
Hi guys. :wavehand:
Reefer Steve
New member
Just curious, what if used in a tank with zero aragonite? Would it be any more or less effective?
MCsaxmaster
New member
Unless you use it in something to the effect of a calcium reactor where pH is very low due to the injection of CO2, it is going to be essentially an inconsequential source of calcium and alkalinity (save for the calcium chloride in it, which WILL add calcium). It might be slightly less effective without a sand bed or rock where it won't be able to work its way into low pH environments, but less of almost nothing is still almost nothing.
cj
Thanks Chris and yes compaction is an issue but I don't think it is all due to compaction. I guess one would have to run real weight tests.
As far as zero aragonite and PU it may be less effective as Chris pointed out for another reason also. Fresh carbonates in seawater at normal pH, Salinity, Alk, Ca++ and Mg ++ have a habit of actually pulling Ca++ and Mg++ out of the water and lowering the pH and Alk at first. These fresh carbonate surfaces in seawater like to grow to a point. They are called surface poisons or surface overgrowths and are made of Hi- Magnesium Calcite. And the affinity or rate of growth on fresh carbonates is also dependant on what kind of carbonate it is, i.e., Calcite, Aragonite, Dolomite etc. However, I really can't speak in terms of 10 micro aragonite in all certainty, as all lab test done are on sand or gravel
As far as zero aragonite and PU it may be less effective as Chris pointed out for another reason also. Fresh carbonates in seawater at normal pH, Salinity, Alk, Ca++ and Mg ++ have a habit of actually pulling Ca++ and Mg++ out of the water and lowering the pH and Alk at first. These fresh carbonate surfaces in seawater like to grow to a point. They are called surface poisons or surface overgrowths and are made of Hi- Magnesium Calcite. And the affinity or rate of growth on fresh carbonates is also dependant on what kind of carbonate it is, i.e., Calcite, Aragonite, Dolomite etc. However, I really can't speak in terms of 10 micro aragonite in all certainty, as all lab test done are on sand or gravel
MCsaxmaster
New member
Boomer,
Agreed, I don't think that compaction explains 100% of the loss of sand, but I do think it explains most of the change in depth. I'm certain some dissolution does occur within the sandbed (and within rock and any place with locally low pH), but the rate is quite low. Usually a change in sand depth is noticable after many months to years. Even if 100% of this was being lost to dissolution the tank would still be woefully undersupplied with calcium and carbonate to fulfill the demands of calcifiers in all but the lowest demand scenarios.
As you mention, often a noticable effect upon adding aragonite to sea water with chemistry like in the surface ocean is a REDUCTION of calcium and alkalinity concentrations. The normal state and the one in which we want to keep our aquariums is one of significant supersaturation (~300 - 500% in nature, sometimes higher in aquariums). This favors precipitation of aragonite, and hence our critters calcify rapidly. By adding a whole lot of nucleation sites we encourage the tank to move toward equilibrium which is in fact lower calcium and carbonate concentrations (assuming constant pH). Yes, once hi-mag calcite covers enough of the surface the rate of precipitation does slow down dramatically, but by that time we've depleted our calcium and alkalinity by some amount.
At normal sea water chemistry this stuff simply won't dissolve, and in fact will induce some abiotic precipitation of CaCO3, lowering calcium and alkalinity. The only way to get much of this to dissolve is to lower pH, dramatically increase pressure, or both. That's how the ocean does it. If somebody wants to hook their tank up to a big sump where they dose aragonite, inject CO2 (or organic material to decompose) and push the pressure to a couple hundred atmospheres, this will work fine and will be a reasonable mimic of nature. That, however, seems a bit much to me
Agreed, I don't think that compaction explains 100% of the loss of sand, but I do think it explains most of the change in depth. I'm certain some dissolution does occur within the sandbed (and within rock and any place with locally low pH), but the rate is quite low. Usually a change in sand depth is noticable after many months to years. Even if 100% of this was being lost to dissolution the tank would still be woefully undersupplied with calcium and carbonate to fulfill the demands of calcifiers in all but the lowest demand scenarios.
As you mention, often a noticable effect upon adding aragonite to sea water with chemistry like in the surface ocean is a REDUCTION of calcium and alkalinity concentrations. The normal state and the one in which we want to keep our aquariums is one of significant supersaturation (~300 - 500% in nature, sometimes higher in aquariums). This favors precipitation of aragonite, and hence our critters calcify rapidly. By adding a whole lot of nucleation sites we encourage the tank to move toward equilibrium which is in fact lower calcium and carbonate concentrations (assuming constant pH). Yes, once hi-mag calcite covers enough of the surface the rate of precipitation does slow down dramatically, but by that time we've depleted our calcium and alkalinity by some amount.
At normal sea water chemistry this stuff simply won't dissolve, and in fact will induce some abiotic precipitation of CaCO3, lowering calcium and alkalinity. The only way to get much of this to dissolve is to lower pH, dramatically increase pressure, or both. That's how the ocean does it. If somebody wants to hook their tank up to a big sump where they dose aragonite, inject CO2 (or organic material to decompose) and push the pressure to a couple hundred atmospheres, this will work fine and will be a reasonable mimic of nature. That, however, seems a bit much to me
ginger7286
New member
I have the W/M cal max is this good in a reef tank to maintain alk/cal? I have stopped using the PU. Thanks
