Interesting Case

[sphelps]

I met another reefer the other night and I was taking a look at his tank and talking about some of the routine maintenance he performs and I was blown away to discover he has to clean his return pump and skimmer pump every 2 weeks or they will physically stop working due to lime build up. It’s become such a routine that he has two spare pumps which he switches out every two weeks. The pumps are MAG 1800, his tank volume is about 160 gallons and it’s moderately stocked with about a dozen smaller SPS colonies, 3 clams at 4” and maybe half a dozen larger LPS corals. I wouldn’t consider it a high demand tank but he claims he needs to dose 400mL/day of Calcium and 800mL/day of Alk supplement just to keep his calcium at about 420 and Alk at about 8.2. He’s using Randy’s recipe #1 and he also doses Kalk through his top off.

It seems obvious he’s overdosing a ton but his PH sits at 8.2 and he claims he’s verified his test readings multiple times with different tests kits including Salifert, Seachem and Hanna. The recommended dosage for his tank should be in the range of 80mL/day but he’s dosing 5 to 10 times that plus the Kalk.

I thought it was a bit of an interesting case so I’m opening it up for discussion. All his corals look fairly healthy, SPS are a little washed out but he’s using a lot of carbon and GFO. He also skims very wet and consistently changes water weekly at a rate of about 5%, uses H2Ocean salt and RO/DI.

[mark]

Been using a reactor for my needs but go years between cleaning on my pumps and even then it's more just a thin slime coat.

Every 2 weeks, is he dosing directly in front of the pump's intakes?

[sphelps]

Been using a reactor for my needs but go years between cleaning on my pumps and even then it's more just a thin slime coat.

Every 2 weeks, is he dosing directly in front of the pump's intakes?
Not really, he doses directly into sump after skimmer and a couple chambers back from return.

[phi delt reefer]

maybe a second set of eyes should check his testing. those tests all use a color scale and he could be interpreting them wrong or looking at them in the wrong light, etc.

Sphelps - maybe he can bring you a water sample and you could test it and report back?

[cathyg_99]

maybe his RO unit isnt filtering enough out of the water? thats why hes getting a build up... as for the dosing that seems really high, id have someone else do my testing for me

[Aquaria]

It's got nothing to do with the rodi I know people who use tap water and if that's the case should they not have the same problems?

[Delphinus]

My guess is low magnesium. Before I would track magnesium, I noticed calcium buildup on many of my pump's magnets and shafts. Powerheads .. skimmer pumps .. etc. Calcium precipitates easily when Mg is low. This effect has been profoundly reduced since keepng Mg where it should be. Now I still notice some buildup on the Tunze magnets but nothing that needs to be removed more than say once every 6 months or so.

[Lance]

Does the sump chamber where he doses have fairly low flow, or is he dosing the calcium and alk too soon to each other? I had the same problem for awhile in the 90g, (though not as extreme). I use the same recipe, and found if I dose the calcium and the alk into the same chamber I have to make sure there is at least 6 hours between the dosing times or I get calcification. In fact the water in that chamber was even a little milky from the two reacting together. I eventually moved the calcium dosing line to a different part of the sump that has more flow and that helped a lot. Within days after doing this the volume of calcium and alk I needed to dose to keep parameters in line dropped considerably.

[asylumdown]

This sounds exactly like what was happening to me when my water chemistry went weird.

a) what alk supplement is he using? is it baking soda from a grocery store, or something prepared specially for reef tanks? I know they're supposed to be essentially the same, but when I used baking soda, my water chemistry went haywire, and the ratios of solution made no sense. I also ended up with pumps failing weekly due to precipitation.

b) is he adding carbonate or bicarbonate as his alk source (carbonate would be if he's 'cooking' his bicarbonate)? With pH levels and dosing volumes both being that high, I suspect he's adding something with a lot of carbonate, which is considerably less soluble and more likely to precipitate out than bicarbonate.

c) It sounds like he's adding so much carbonate/bicarbonate that his levels are never balanced. Is he using an auto-doser? If he's pushing one past the 'limit', addition of the other will instantly react and precipitate out. I think you can get in to a vicious cycle. I bet at one point in the past he overdosed on one additive (likely alk), which caused a precipitation reaction that depressed his levels of calcium. On a test kit, it would have looked like he had low calcium and normal alkalinity. If he's using a doser, he would have then upped the amount of calcium he was adding every day. However, there would still be excess carbonate being added, so the precipitation would continue, and appear to depress his alk levels. So then he upped the amount he dosed alk, which would depress the calcium levels again... so on and so forth, always upping one, seeing a drop in the other, upping it, then seeing a drop on the other side. The end result would still look like he has 'normal' levels in his water, but that's because massive amounts are instantly precipitating out on pumps, etc. If this is the case, he needs to start dialing back on the amounts he's adding in the same way he upped his dosing volumes.

In either case, there's no other answer, he's adding too much. That's the only explanation for the precipitation. The 'normal' levels he's seeing aren't 'normal' at all, they're what's left over after the precipitation of the excess he's added to the system.

[asylumdown]

To add:

If you're finding that you're adding twice as much alk as calcium and you keep upping the amounts of each, I think you should first try dialing way back on the rate you dose alk. It seems counter intuitive, but if you're precipitating out large amounts of additive due to an imbalance, you're not likely going to see normal levels in one, and way high levels in the other, it will look like 'normal' levels of the one you're over-dosing, and low levels of the other.

[PoonTang]

Yes i would say that he is at the point of the "viscous cycle". His tank sounds about the same as mine but my corals are probably larger and my demand may be higher. The only thing i dose is Kalkwasser and never have to add any 2 part except i will tweek the levels every month or so but never by all that much. I wouldnt worry about the ph at all mine sits around 8.0 and if i try to move it higher (such as in my battle with dinos) it just falls back within a couple of hours. Its a no win battle. Cal and alk are a funny thing as we all know, they work fine when they are all balanced but if you get 1 out of wack then it has the opposite effect on the other. This is partly why i prefer the Kalk route, as it is basically balanced to start with. I would check his mag too. I havnt had to clean a pump from calcification in a year and a half and some of the pumps have never been cleaned.

[Red Coral Aquariums]

My guess is low magnesium. Before I would track magnesium, I noticed calcium buildup on many of my pump's magnets and shafts. Powerheads .. skimmer pumps .. etc. Calcium precipitates easily when Mg is low. This effect has been profoundly reduced since keepng Mg where it should be. Now I still notice some buildup on the Tunze magnets but nothing that needs to be removed more than say once every 6 months or so.

I have seen this before. Interested to see the mg levels.
Kevin

[sphelps]

My guess is low magnesium. Before I would track magnesium, I noticed calcium buildup on many of my pump's magnets and shafts. Powerheads .. skimmer pumps .. etc. Calcium precipitates easily when Mg is low. This effect has been profoundly reduced since keepng Mg where it should be. Now I still notice some buildup on the Tunze magnets but nothing that needs to be removed more than say once every 6 months or so.

He doses magnesium weekly to maintain it at 1500

[sphelps]

Does the sump chamber where he doses have fairly low flow, or is he dosing the calcium and alk too soon to each other? I had the same problem for awhile in the 90g, (though not as extreme). I use the same recipe, and found if I dose the calcium and the alk into the same chamber I have to make sure there is at least 6 hours between the dosing times or I get calcification. In fact the water in that chamber was even a little milky from the two reacting together. I eventually moved the calcium dosing line to a different part of the sump that has more flow and that helped a lot. Within days after doing this the volume of calcium and alk I needed to dose to keep parameters in line dropped considerably.
Not super low flow, it's a decent size sump but the mag 1800 is running at full open so the sump turn over rate is pretty high. The alk is being dosed automatically along with the kalk top off but calcium is added manually each day. I believe the full 400ml is added at all at once which could be an issue.

[sphelps]

This sounds exactly like what was happening to me when my water chemistry went weird.

a) what alk supplement is he using? is it baking soda from a grocery store, or something prepared specially for reef tanks? I know they're supposed to be essentially the same, but when I used baking soda, my water chemistry went haywire, and the ratios of solution made no sense. I also ended up with pumps failing weekly due to precipitation.

b) is he adding carbonate or bicarbonate as his alk source (carbonate would be if he's 'cooking' his bicarbonate)? With pH levels and dosing volumes both being that high, I suspect he's adding something with a lot of carbonate, which is considerably less soluble and more likely to precipitate out than bicarbonate.

c) It sounds like he's adding so much carbonate/bicarbonate that his levels are never balanced. Is he using an auto-doser? If he's pushing one past the 'limit', addition of the other will instantly react and precipitate out. I think you can get in to a vicious cycle. I bet at one point in the past he overdosed on one additive (likely alk), which caused a precipitation reaction that depressed his levels of calcium. On a test kit, it would have looked like he had low calcium and normal alkalinity. If he's using a doser, he would have then upped the amount of calcium he was adding every day. However, there would still be excess carbonate being added, so the precipitation would continue, and appear to depress his alk levels. So then he upped the amount he dosed alk, which would depress the calcium levels again... so on and so forth, always upping one, seeing a drop in the other, upping it, then seeing a drop on the other side. The end result would still look like he has 'normal' levels in his water, but that's because massive amounts are instantly precipitating out on pumps, etc. If this is the case, he needs to start dialing back on the amounts he's adding in the same way he upped his dosing volumes.

In either case, there's no other answer, he's adding too much. That's the only explanation for the precipitation. The 'normal' levels he's seeing aren't 'normal' at all, they're what's left over after the precipitation of the excess he's added to the system.

I believe he is using baking soda which he bakes in the oven first. I agree this is the likely the main issue, adding 10x the recommended dosage of this is going to cause a lot of precipitation which builds up on his equipment. The addition of Kalk is likely a factor as well which eats up all the CO2 in the tank, great for keeping algae growth down but not so good for dissolving all the additives.

[Delphinus]

Given that he is dosing Mg then I would agree with your last assessment. But also:

I believe the full 400ml is added at all at once which could be an issue.

I think that is probably it right there, or at least that should be confirmed is the case how it's being added. At the best of times that's quite a sawtooth wave happening, that quick rise in levels is going to have an effect.

[PoonTang]

The Unbaked version (#2) of Randys recipe is the normal one to dose when using Kalk, although i dont know if this would cause any issues. The thing that seems so wierd to me is that he has to add it in such an un-balanced proportion. The 2 part recipies are meant to be dosed in equal portions but he is dosing double the alk as should be needed. Makes me think that something is way outa wack.

[PoonTang]

Given that he is dosing Mg then I would agree with your last assessment. But also:



I think that is probably it right there, or at least that should be confirmed is the case how it's being added. At the best of times that's quite a sawtooth wave happening, that quick rise in levels is going to have an effect.




I would disagree based on personal experience. I have dumped far more than that in my sump with only a short time between the Cal and Alk being added and never have any precip problems. However if his levels are actually way higher than is indicated than it could be a problem.

[Coleus]

You should try to test his water with your test kits and see the reading. My tank is about the same size as his, I also use Mag 1800 and I have not cleaned it for months. I did not clean my return pump for 2 year with my old one until the front plate got broken :-)

I dose around 80ml for both calc and alk with Randy recipe. But only have small- medium sps corals right now.

[asylumdown]

The only time I got precipitation was when I was doing twice the alk as the calcium, and then I was only adding 150ml of alk to 75 calcium and my pumps were fried in a matter of weeks.

This is first year chemistry:

It's an equilibrium reaction. Calcium carbonate isn't totally insoluble, it's just highly insoluble under normal conditions (like a Ksp of 4.0X10-9 or something). At any given moment in all of our tanks, a small amount of very soluble calcium and carbonate ions are reacting with each other and precipitating out. If things are in balance, the amount that precipitates out equals the amount of calcium carbonate that dissolves back in to the water, favouring the aqueous states of carbonate and calcium. It looks like this:
<-----------------------------------
1Ca(2+) + 1CO3(2-) <----> 1CaCO3

This is highly simplified standard temperature & pressure equation, and when things are normal, you need to worry about pH, carbonic acid/bicarbonate levels, magnesium levels, reaction of carbonate with other ions, uptake by corals, etc. to determine the exact nature of that relationship and how much calcium carbonate you'll produce. But in a balanced system, those other elements that affect that reaction will never lead to pump failures. We're talking about affecting the appearance of molar quantities of calcium carbonate so small you will never, ever notice it in a balanced system (and can barely even measure outside of a lab).

He's adding so much of each, and in such disproportionate ratios, that none of those other, more subtle elements are going to matter. When you provide a gross excess of either of those ions in a solution, you shift the arrow of that equilibrium reaction so that it looks like this:

------------------------------------->
1ca(2+) + 1CO3(2-) <----> 1CaCO3

all the other factors, pH, the relationship between carbonate and carbonic acid/bicarbonate, magnesium levels etc. - none of that matters if you dump so much of one of the primary ions in the above reaction in to the water that you shift the equilibrium way to the calcium carbonate side. Those things are still going on and are important in balanced systems, but the net result of what he's doing is exactly what he's seeing, ruined pumps on a weekly basis.

He's spending money on additives to plate his tank in calcium carbonate.

If I were him, I would stop dosing all additives until things have balanced themselves out. His levels will crash, which will be stressful on the system, but once they're down he can start bringing them back up in a balanced way again.

[trilinearmipmap]

My guess is low magnesium. Before I would track magnesium, I noticed calcium buildup on many of my pump's magnets and shafts. Powerheads .. skimmer pumps .. etc. Calcium precipitates easily when Mg is low. This effect has been profoundly reduced since keepng Mg where it should be. Now I still notice some buildup on the Tunze magnets but nothing that needs to be removed more than say once every 6 months or so.

+1

[sphelps]

I've got him to cut back on dosing to 100mL/day of each and stop the kalk altogether. I wanted him to stop all dosing for a bit so see how things balance out but he wasn't that comfortable with that so we settled on a much lower and balanced dosing schedule. I will be maintaining his tank for 9 weeks this summer so I guess we'll see if I can sort things out a little for him.

[StirCrazy]

I've got him to cut back on dosing to 100mL/day of each and stop the kalk altogether. I wanted him to stop all dosing for a bit so see how things balance out but he wasn't that comfortable with that so we settled on a much lower and balanced dosing schedule. I will be maintaining his tank for 9 weeks this summer so I guess we'll see if I can sort things out a little for him.

did you find out if he is dosing all at once.. if so I am willing to bet this is the problem. he needs to spread his dosing out though the day. some in the am, some at lunch, some after work some befor he goes to bed.

my guess is that when he doeses he creats a temporary high concentrating in the sump which will percipitate easily then as it is mixed it is dropped back down to a normal level.

I had the same problem befor I put my Ca reactor online. actualy that was the reason I went to a Ca reactor and a Kalk reactor.

Steve

[sphelps]

The alk was dosed automatically throughout the day and the Ca was dosed all at once each day. While I agree dosing this much at once is a problem the main issue is the amount. Any tank should be able to handle a daily dose all at once provided it's not an overdose.

[Delphinus]

True.... although ... it's still better to add it slowly than all at once. It takes time to mix in and become homogenous.

Now that I think about it some more, that was something I used to do when I had calcium buildup in the past, I'd just do Ca in the morning and Alk at night and just dumped it into a fast moving part of the sump or the overflow itself. It still takes a little while to dissipate into the overall tank volume and in that time what's happening? This is going back like 10 years or more so memory is faded a little, but I did used to dose 2-part, then I thought that was for the birds, went to a Calcium reactor and also thought it was remarkable that the Ca reactor, although maintaining less ideal values than the dosing did, the growth in the tank was better (and the calcium buildup was gone). Fast forward a few years and the pendulum swings the other way, I conclude that CO2 cylinders are for FW tanks (instead of birds this time) and I go back to dosing but this time using timers and slow dosers, adding slowly and spread out over the day (while still alternating Ca/Alk) and yeah it's like the best of both worlds. Nicer params, good growth and no ca buildup in impellers.

In your friends case it's probably a combination of factors that each on their own wouldn't be enough to cause it but in concert together they are.. That's my guess anyhow. Should be interesting to see, 9 weeks should be plenty of time to get it sorted and settled, methinks anyhow..

[sphelps]

Yeah I'll be making a few changes to start with and all the dosing will be automatic throughout the day, but for now I just needed him to cut back.

[StirCrazy]

The alk was dosed automatically throughout the day and the Ca was dosed all at once each day. While I agree dosing this much at once is a problem the main issue is the amount. Any tank should be able to handle a daily dose all at once provided it's not an overdose.

sorry was at work for the last two days.

it isn't that the tank can't handle it, but rather when you dump that much Ca in at once the sump Ca level is probably spinking over 1000ppm untill it gets mixed completly with the total volume of the system.. these levels cause percipitation hence the frequent cleening of the pumps.

as for the amount you will find that once you spread out the dosing in snaller amounts through out the day the consumption will drop due to less percipitating out of solution. his tank isn't realy using that much but his pumps are :mrgreen:

PS. don't test and comeback saying he is not over 1000ppm it was just a number I grabbed out of think air to make the point ;) but depending on the size of the sump it may be an accurat number or not.

Steve