how to calculate kalk dosing

[imisky]

hey guys,

 

i have always wondered how to calculate the amount of calcium that your tank is taking in, so you can dose it back in with kalk

 

and how does one calculate how much kalk is needed to be added into a volume of RODI water so it can be dripped or dosed in via a dosing pump. is there a calculator for that?

 

thanks

[Kirin1]

Most people who use Kalkwasser replace all their evaporated water with Kalk. When added drip-wise by an ATO system that's controlled by a float switch or two, it's not really possible to overdose kalk. (Assuming everything functions properly.) If you've got or are getting a peristaltic pump, set it to deliver a few drops per second, and have it switched on/off by a float switch.

 

On mixing kalk, I believe it's 1-3 teaspoons per gallon. I used to drip kalk at night from a siphon bottle. I mixed my kalk in 1 gallon batches, with 1 heaping teaspoon per.

 

HTH

[Imaexpat2]

Yes I guess I am most people cause thats exactly what I do...slowly drip Kalk for all top off water lost due to evaporation. I too mix one tea spoon per a gallon which I use to fill a 1 qt drip bottle that I made. This has been working good for me for the last 4 years without issue in a number of tanks from 300 gallons to 10 gallons.

[imisky]

Yes I guess I am most people cause thats exactly what I do...slowly drip Kalk for all top off water lost due to evaporation. I too mix one tea spoon per a gallon which I use to fill a 1 qt drip bottle that I made. This has been working good for me for the last 4 years without issue in a number of tanks from 300 gallons to 10 gallons.

 

thanks guys for the reply, my only concern at the moment is i am using an aquaclear powerhead as the top off pump which delivers quiet alot of water at once instead of slowly topping it off. Im sure this will cause some problems as kalk mixed RODI water has a very high pH level. i dont really have the option of adding a bottle on top of the tank as there is no shelving above.

 

so i guess my question now is, is it alright to use a powerhead for a top off pump? or does it top off too much and will effect the corals.

[Mr. Fosi]

If you intend to top off using kalk, a powerhead is not preferable.

 

You can easily use an airpump and a pressure cannister instead of a powerhead and tub.

 

I use a 3L bottle with two holes in the cap. I have a whisper airpump that pressurizes the bottle and pushes kalk out.

[Mr. Fosi]

I just realized that no one answered the original question: how to calculate Ca/alk usage.

 

Simple. Get your Ca/alk where you want it then track it over the next several days. That'll give you a curve of usage. Do it again and again and average your results.

 

It shouldn't be too hard to figure out how much Ca(OH)2 goes into solution in FW... Take that info and combine it with your average usage and bang! You have your answer.

 

Of course, this measurement can be skewed by lot of stuff but you may get something you can use.

[imisky]

I just realized that no one answered the original question: how to calculate Ca/alk usage.

 

Simple. Get your Ca/alk where you want it then track it over the next several days. That'll give you a curve of usage. Do it again and again and average your results.

 

It shouldn't be too hard to figure out how much Ca(OH)2 goes into solution in FW... Take that info and combine it with your average usage and bang! You have your answer.

 

Of course, this measurement can be skewed by lot of stuff but you may get something you can use.

 

thanks Mr.Fosi,

 

so in order to measure the calc/alk consumption rate i should do a water change and get my levels to where they should be, than test how much is being used in 1 day? and after that day get the levels back to where they should be again and repeat?

 

or just get the levels where they should be and let it got for 2-3days

 

as for topping off with kalk, what is the best way to top it off with a pump? im assuming it would be using a dosing dump..something that can dose 1~2mls of solution at a time instead of 5~6. The idea of a 3L bottle with a air pump sounds like it could work, but how ridgid does the canister have to be? and how fast does it top the tank off now i just have to find a container which is perfectly sealed and can handle pressure if i was to use the air pump method

[Mr. Fosi]

I think you'll find that the Ca/alk usage is something approximating a logarithmic decay with the asymptote being somewhat above zero. You'd have to take a lot of data points to elucidate the curve though.

 

I would test every day for a week, then do a waterchange and do it again. This assumes that your waterchange will get your levels back up to the starting line. If a week is too long, you could do it over as few as 3 days, but you really want to have 5 or more days because it will improve your average and perhaps your standard deviation.

 

The idea of a 3L bottle with a air pump sounds like it could work, but how ridgid does the canister have to be? and how fast does it top the tank off...

 

Not could work, does work. I have been using it for ~1 month and it looks like it is set to go for many more. The rigidity isn't the issue, the seal is. You could use a ziplock bag as your top off reservoir so long as the seal will hold.

 

Some people have used brand new, never used gasoline containers but that plastic isn't rated for potable usage so I wouldn't use it on my tank. Almost anything with a screw-on lid will probably work.

 

now i just have to find a container which is perfectly sealed and can handle pressure if i was to use the air pump method

 

Not that hard. We're not talking about a lot of pressure and if you use a really beefy air pump, the seal doesn't have to be that great either.

[imisky]

I think you'll find that the Ca/alk usage is something approximating a logarithmic decay with the asymptote being somewhat above zero. You'd have to take a lot of data points to elucidate the curve though.

 

I would test every day for a week, then do a waterchange and do it again. This assumes that your waterchange will get your levels back up to the starting line. If a week is too long, you could do it over as few as 3 days, but you really want to have 5 or more days because it will improve your average and perhaps your standard deviation.

Not could work, does work. I have been using it for ~1 month and it looks like it is set to go for many more. The rigidity isn't the issue, the seal is. You could use a ziplock bag as your top off reservoir so long as the seal will hold.

 

Some people have used brand new, never used gasoline containers but that plastic isn't rated for potable usage so I wouldn't use it on my tank. Almost anything with a screw-on lid will probably work.

Not that hard. We're not talking about a lot of pressure and if you use a really beefy air pump, the seal doesn't have to be that great either.

 

Thanks again Mr.Fosi for the detailed explaination

 

one last question on the measuring, once i get my ca/alk levels to where they should be, i dont dose for that whole week?

 

im guessing that it would be cheaper to use the air top off then a dosing pump as those are expensive, which type of plastic should i be looking for? when picking out a container to hold the kalk solution

[Mr. Fosi]

You don't want to dose during your week of measurements because you want to see whether the usage changes. I suspect that usage will go down as Ca goes down because there is less Ca to use and the uptake mechanisms probably have a threshold below which they cease to function efficiently. The only way to know is to watch the usage for several consecutive days. You would probably have to go for somewhat more than a week to figure out what your tank's threshold is, but I doubt it is worth knowing.

 

Keep in mind that your usage will change over time. As you get more coralline, they will use more Ca. Same with LPS or other calcerous corals; the bigger they get the more Ca they will use. This means that you will have to re-check your usage every so often if you plan to try and match your kalk addition. How often? Beats me, you'll have to figure that one out.

 

For the kalk, I would look for something made of polyethylene (pop bottle material). It is fairly non-reactive and won't break down when exposed to the high pH of kalk. It is also safe to store potable water in, which is good because you don't want to release all kinds of strange organics in your tank. You can buy carboys made of this material from places like Fisher Scientific or other such vendors. I have a couple 2g jugs but you could get one as big as 5g if you like.

[imisky]

You don't want to dose during your week of measurements because you want to see whether the usage changes. I suspect that usage will go down as Ca goes down because there is less Ca to use and the uptake mechanisms probably have a threshold below which they cease to function efficiently. The only way to know is to watch the usage for several consecutive days. You would probably have to go for somewhat more than a week to figure out what your tank's threshold is, but I doubt it is worth knowing.

 

Keep in mind that your usage will change over time. As you get more coralline, they will use more Ca. Same with LPS or other calcerous corals; the bigger they get the more Ca they will use. This means that you will have to re-check your usage every so often if you plan to try and match your kalk addition. How often? Beats me, you'll have to figure that one out.

 

For the kalk, I would look for something made of polyethylene (pop bottle material). It is fairly non-reactive and won't break down when exposed to the high pH of kalk. It is also safe to store potable water in, which is good because you don't want to release all kinds of strange organics in your tank. You can buy carboys made of this material from places like Fisher Scientific or other such vendors. I have a couple 2g jugs but you could get one as big as 5g if you like.

 

thank you so much helped alot!