2 Part Dosing Question

[Ryan S]

Assume the following:

 

You have two 25g barrels in a fish room, one full of alk solution, one full of ca solution. You bought this for the calcium, and this for the alkalinity. You also bought this for the magnesium, but it's not in a 25g barrel or anything. Each of the two 25g jugs is hooked up to one of these, which is on a digital timer, so it puts the exact dose of cal and alk into your tank everyday. The total cost you spent for this equipment is $500.

 

Each 25g barrel holds 94,000mL of solution. I currently dose 50mL/day of Ca and Alk. At 50mL/day, the barrel would last 5 years before it was empty! If you dosed more, such as 100mL/day, the barrel would last 2.5 years!

 

Note: the bulk ca, alk, and mag that you bought, actually makes 160 gallons of solution. So even after the 25g barrel is empty, you have plenty of solution left to use. In fact, at 50mL a day, it would take you 33 years to use it all! Or at 100mL a day, it would take 16.5 years! So 16.5-33 years of Alk, Ca, and Mag, for under $500!!

 

Since I've never seen a totm do this, and most use kalk reactors and/or ca reactors, could someone tell me what I am missing? It seems to me like 2 part should be the majority in systems, not in the minority, at least if my math is correct???

[lanman]

I use 2-part in my frag system; and it is usually the best looking of my three different systems, with good consistent growth. I purchase my 2-part, though; so it is a lot more expensive.

 

bob

[Origami]

First off, there are cultural aspects for the answer to your question, I think. For example, in Europe, where the Balling Method is more prominent than here, those tanks depend on a multi-part approach, similar to your two part. Here, we might do things differently.

 

Second, it's about convenience and consumption.

 

For convenience, Kalkwasser and calcium reactors are naturally balanced additives. Kalkwasser has the added benefit of being able to be tied thru your top-off system so you're not adding another system to monitor. It's also far less concentrated, so overdoses require significantly more additive to reach the same level.

 

Regarding consumption, let me focus on calcium uptake. A similar discussion would apply for alkalinity with the numbers being different.

 

At 50 ml per day, you're dosing ~1.850 grams of calcium per day since your calcium part has 37,000 ppm ((37,000 mg/kg) Ca. Kalkwasser is significantly less concentrated at 808 ppm - that's 45.8 times less. This means, you'd have to dose 2.29 liters (0.6 gallons) of saturated kalkwasser every day to deliver the same amount of calcium to your tank as you're getting in that 50 ml of your Part 1. However, if you're having to replace that much water to evaporation every day, kalkwasser is a simple and even cheaper alternative to (automated delivery of) two-part. (Kalkwasser has additional benefits that I won't get into such as precipitation of phosphates and some metals, and helps to maintain a good pH.)

 

However, when consumption (uptake) of calcium by your corals and other skeleton-forming inverts exceeds the amount that you can deliver in kalkwasser because, fundamentally, you can't dose more than you evaporate, other supplementation strategies are required. This can include replacing or augmenting the dosing system with two-part or with a calcium reactor.

 

As an example, in my system, I use both a kalk stirrer connected to my ATO and a calcium reactor. My kalk stirrer runs 35 minutes out of every hour, 24 hours a day, 7 days a week, replacing the 14 liters (3.7 gallons) lost every day to evaporation. In the process, I add 11.3 grams of calcium every 24 hours by this method. Unfortunately, this doesn't match my consumption, so I elected to add a calcium reactor (having found a good deal on a used one) to the system. At this time, I run 24 liters a day through the calcium reactor which doses another 6.85 grams of calcium (assuming my effluent's around 40 dKH - which normally it is) every day. In total, my system consumes around 18 grams of calcium every day on average right now and my corals are still, for the most part, small. I'd have to dose around half a liter of your Part 1 every day to match today's consumption. In the future, if I need more, I just have to increase the flow out of the calcium reactor. Still, when I do have an imbalance, I supplement with solutions normally used in multi-part dosing (calcium chloride, sodium bicarbonate, or magnesium chloride / sulfate and, rarely, strontium chloride).

 

As for economy, I don't have the exact math for you (though it could be easily calculated, I suppose). But if I were to do so, I would consider not only the aquisition cost but also the resale value of equipment, and the operations costs associated with the materials (supplements). While, as you've observed, there's some difference between the equipment cost, there can also be a significant difference in material costs. Lime and calcium reactor media can be pretty cheap when compared to some chemical supplements, though even these expenses can be brought down if you use commonly available substitutes.

 

Hope this was helpful.

[Boret]

I am currently using a very similar setup to Origami's for my tank. A Kalkwasser stirrer connected to the ATO and a Calcium Reactor running 24/7 (unless the pH runs too low -- which normally means I have to add line to the kalk stirrer).

When I first researched this subject I came across this article. It is a very good guide for aquarium chemistry. The most interesting part for me was towards the end where the author displayed this chart:

 

[Boret]

Another table from the article that presents some interesting info:

 

[Origami]

Thanks, Boret. I would add, though, that two-part using generic chemical substitutions like Randy's Improved 2-Part recipe, ( http://reefkeeping.com/issues/2006-02/rhf/index.php ) can be made much cheaper by the DIYer than what was listed in his 2003 article.

 

For example, you can use Dow or Tetra calcium chloride for calcium supplement; good old Arm and Hammer baking soda for the alkalinity supplement; and Mag flake or pellet plus Epsom salts to supplement magnesium. Dow flake should run under $20 (locally) for a 50# bag, baking soda is cheap at the grocery and even cheaper at Cosco, and Mag flake costs under $20 (locally) for a 50# bag. So there are cheaper ways than what was presented in the original article.

Edited July 2, 2009 by Origami2547

[Boret]

Well, the chart also doesn't account for the initial setup cost of two-part systems. You can go the easy/cheaper route and use a gravity drip mechanism, or you can get fancy and use peristaltic pumps that will make it more expensive.

[Origami]

Well, the chart also doesn't account for the initial setup cost of two-part systems. You can go the easy/cheaper route and use a gravity drip mechanism, or you can get fancy and use peristaltic pumps that will make it more expensive.

 

I hadn't noticed that. That should certainly be added and Ryan's accounted for that in his original post. That's the convenience / stability factor. Fixed costs are, in one sense, recoverable (in part or, if buying used, often in large part), so I consider them secondary to operational costs. Those big numbers that Randy had in the operational columns were assuming use of B-Ionic's product line rather than to use generic substitutions. At the time (in 2003), I don't think Randy had done his analysis on chemical substitutes. His subsequent work in this area has enabled a lot of people to save a lot of money, and still remain confident in the quality of the additive they're dumping into their systems.

[Boret]

Hey Tom, did he (Randy) put together an updated version of the article? Have you found any recent cost break down for more up to date solutions?

[basser9]

I f you have the room for good sized containers 2 part is the way to go......hate anymore pumps on my system then nessary......fill my 10 gall 2 part cont very rarely way cheaper and less things to go wrong......diy 2 part is the best if you check around you can find all the stuff local and cheap.....my 50 lb bag of Dow last me 2 years at 25.00

[Ryan S]

Hey Tom, did he (Randy) put together an updated version of the article? Have you found any recent cost break down for more up to date solutions?

 

That's a good chart, but it's a little outdated now? B-ionic was, and is, way more expensive than buying the Ca and Alk in bulk, such as from BRS.com. It would be cool to see an updated table with them included in it. I am sure they would be the cheapest yearly, and over time.

 

Origami - If you dosed 500mL/day, of the 2 part system, as described initially, with that $500 investment, even on your demanding system, it would still last 40 months, or 3.3 years. If you used the 25g barrels, they wouldn't be empty for 188 days (or 6 months) at a time. That's pretty nice...

Edited July 2, 2009 by Ryan S

[Origami]

Hey Tom, did he (Randy) put together an updated version of the article? Have you found any recent cost break down for more up to date solutions?

 

No. I don't think he updated the article. I think the selection criteria remain pretty much the same. The costs are what may differ today. In the end, as operating costs drop, it's not cost that becomes the deciding criteria. It's other factors. Factors such as convenience, quality, risk, start-up cost, continued availability of supplies (chemicals), etc. A special note on the last part: It wasn't that long ago when Dow announced that their Dowflake product would undergo a change in processing, resulting in increased bromide. It was unknown at the time what the implications of this would be on the reefkeeping hobby. Consequently, reefers using two-part scrambled to buy up bags of Dowflake from older lots known to have come from the old processing method. As those bags became more and more scarce, some people were compelled to go back to using more expensive chemicals (name brands and stuff from BRS, for example), while others just started using whatever they could find (and crossing their fingers). It wasn't until rather recently that the bromide question was "answered" and some comfort was restored to many reefers who's daily peace hang in the balance of such questions, and that some acceptability to Dowflake has been restored. (BTW, Tetra has an excellent process and their CaCl2 finds use in many aquariums. And, as late as last year, Tetra made some of it's CaCl2 in the same plant - in China - that makes CForce Calcium Chloride.) Without cheap trustable sources like DowFlake and MagFlake, we would be forced to use more expensive chemicals, thereby changing the cost dynamic of this trade once again.

 

In the end, I spend so much on this hobby that goes well beyond the amount to be gained by anwering this argument, that the answer (if there really is one) doesn't really matter. For me, it's a question of can the method keep up with demand, how convenient is it, and what additional benefits and risks come with it.

 

As it is now, I service my kalkstirrer once a week (I never keep a whole lot in it for safety reasons) and can run my calcium reactor for ages before it needs attention. That averages out to maybe 5 minutes a week. There's more to be gained from optimizing other parts of my system than this part.

[Origami]

Origami - If you dosed 500mL/day, of the 2 part system, as described initially, with that $500 investment, even on your demanding system, it would still last 40 months, or 3.3 years. If you used the 25g barrels, they wouldn't be empty for 188 days (or 6 months) at a time. That's pretty nice...

 

Yes. But my system's young (and not really demanding). That amount would be expected to increase.

 

I don't like mixing chemicals up for a six month run, to tell you the truth, so I'd be unlikely to mix up 25 gallons at a time of two-part. There's two reasons for this: The first reason is simple: Concentrated solutions of aqueous calcium chloride, when exposed to carbon dioxide, will begin to precipitate insoluble calcium carbonate, thereby weakening the solution. Try this: Mix up a strong solution of calcium chloride in a clear glass and blow bubbles through it using a straw. You should see the clarity of the solution begin to drop as calcium carbonate is formed. The same problem exists for calcium hydroxide (lime, kalk) by the way. That's what the crust is that forms on the water's surface in kalk stirrers - calcium carbonate. (Once the film's formed, though, it hinders the further absorbtion of CO2.) Just like I'd never make up six months of kalkwasser, I'd never make up six months of calcium chloride.

 

The second reason is risk. I'd never tie in 25 gallons of any concentrated chemical, or even an unlimited source of fresh water, to my system without appropriate safeguards and redundancy to those safeguards.

 

But that's just me. I accept that others come to different conclusions and do things differently. It's that variability in what we do and our results that makes this forum of sharing exciting and educational. If it were one size fits all, it would be pretty boring.

Edited July 2, 2009 by Origami2547

[Boret]

Thanks Tom it is always a pleasure to read you thoughts on these and many other subjects.

I like tinkering with my system.... which it's probably not a very good idea, but it is really appealing to try different and new things.

 

I end up going for the Ca Reactor and the Kalk stirrer because I got both used for great prices.

 

The stirrer is the small of the old style from GSA. It works great and have been in service for about 3 and 1/2 years between previous owner and myself. I run it with a JBJ ATO which I have been using for about 2 years. The ATO will stop pumping after 3 minutes in case the float switch gets stuck. Works like a charm but I am looking into more redundancy. I don't want to deal with a kalk overdose.

 

I got the stirrer and about 40lbs of Missisipi Lime for about $100.

 

I got a great deal on a KNOP reactor (the smallest one), 5lb CO2 canister and CO2 regulator. The Ca reactor used to turn on when the pH reached a set level, in my case 8.30. I was advised to run it 24/7 so that is what I do now. I still have it so it will stop the CO2 when the pH in the tank reaches 8.00 but otherwise stays on all the time. I can throttle both the CO2 bubbles and the amount of water flowing from the sump into the reactor and back into the sump. I paid $175 for the whole thing including 10lbs of media.

I have been using the same CO2 canister for over 9 months since I last refilled it. ($15 refill)

I added an aqualifter pump to feed the reactor. $10

 

So far I have spent $300 total for the setup and media. I probably have enough Lime for about 50 years!!! I have enough Ca Media for about 2 years maybe more.

[Ryan S]

Thanks Tom it is always a pleasure to read you thoughts on these and many other subjects.

 

x2. And same to you Boret for your input. I am sure one day I'll have a kalk and ca reactor. I just need to find a good deal on both like you did Boret!

Edited July 3, 2009 by Ryan S

[nelson_crn]

These might be total newb questions....does 2-part degrade over time? Is there any risk that 3 months down the line the remaining solution will (for lack of a better term) "spoil"? What about bacteria growth in the low flow/stagnant sloutions (or would you have a circulating pump in your 25g containers)?

[F&Fmgr]

fwiw, i run a calcium reactor and kalk reactor everyday, all day in my sps system which is ~ 400 gallaons. I maintain huge growth rates and my calcium sits at 500 ppm + and dKH is between 14-16. I know thats high, trust me I know, I'm the one that cleans and replaces the impeller sets on every pump twice a month. BUt some thing to think about, even at maintaining levels that high my cost is very low, initial cost was low as well because I built the CA reactor from a prefab canister. So for the average hobbyist, who would maintain 400-450 ca and 9-12 dkh, the cost would be substantially lower than mine, which is already very low. I have a five gallon bucket of kalk from BRS that is still 9/10's full and ive refreshed two kalk reactors about six times each on this one bucket. for the calcium reactor i use a mix of Bwel's Neo Mag, Aqua medic's hydro carbonate, and carib sea coarse ARM. Ive tested potassium, strontium, calcium, magnesium, and alkalinity. Between the two systems, my average cost per two months ( i only added calcium reactor medium 6-7 times per year) is around 25-30 bucks. Now that's on a 400 gallon sytem packed with sps. If I take the systems off line i drop about 100-150 mg/l of calcium every 24-48 hours and my alk drops rapidly. I guess for me, if I could afford to dose B-ionic and not have to raise my prices I would because ive seen alot of before and after pics and it is a solid product. It grows softs as well because of the iodide in the formula. The mix of calcium reactor media that I use gives all of the major and some of the minor elements, i dose a supplement for all of the trace.

 

Just thought id chime in

 

Sean

[Coral Hind]

Sean, Thanks for bringing back a slightly old thread. I missed this the first time. About how many gallons of kalk water do you add a day to you system?

[dtfleming]

I have a smaller tank then most of you. In my 40br I dose 50ml of 2-part a day. I made my own DIY doser for both that doses 10ml 5 times a day throughout a 24hr period. I have to check them from time to time, but they work well and coral growth is excellent. In a system like my its cheaper to dose 2-part then a bigger system. If I had a bigger system I would def have to go the reactor route.

[dtfleming]

I have a smaller tank then most of you. In my 40br I dose 50ml of 2-part a day. I made my own DIY doser for both that doses 10ml 5 times a day throughout a 24hr period. I have to check them from time to time, but they work well and coral growth is excellent. In a system like my its cheaper to dose 2-part then a bigger system. If I had a bigger system I would def have to go the reactor route.

 

Oh, I should add that I add a tablespoon of Kalk to my 5gal ATO container once in awhile.