Advice from the chemistry god.....:)

[Lousybreed]

Randy, I am a big fan of yours. I have followed you for years, but only started reefing like 1.5 yrs ago. I am a chemical engineer, so I enjoyed your articles. Inorganic chemistry in an organic system, super interesting for sure!!!!

Things have gone well so far. I am using kalk for my 80 gal system that i am currently running. My only actual question is what is the saturation of kalk? I found on the web 1.73g/L of RODI at 70F. I never fact checked this with literature or you. Is this the correct saturation level?

Anyways I am in the stages of planning a 240 gallon system now. For the 240 system I am leaning towards a Ca RX but still dose a bit of kalk for pH stability. I feel that a Ca RX does free up other elements that are vital for coral growth. I just sent out my water for ICP testing via Trition. I am expecting to find major deficiencies in my trace elements since kalk doesnt supply any. I have been eyeing up going with the Ca RX and dosing Red Sea's trace elements. The triton method is waaaaay too expensive for me. Plus I dont agree that water changes are not needed. At some point there has to be some untested stuff that builds up. So my thoughts are small water changes (5% every other week) Ca RX, and trace dosing.....if you have any opinions they would be welcome!!!

 

[Lousybreed]

I should add that I have a scale and I prefer to not use the "2 tablespoons of kalk per gallon of water" adage. I mix large quantities of kalk at a time with a calibrated barrel. Fill it up, calculate the amount of kalk needed, weight it out, and mix it for several minutes....

 

[sundog101]

Randy you have fans!

 

[Randy Holmes-Farley Verified Community Expert]

Randy, I am a big fan of yours. I have followed you for years, but only started reefing like 1.5 yrs ago. I am a chemical engineer, so I enjoyed your articles. Inorganic chemistry in an organic system, super interesting for sure!!!!

Things have gone well so far. I am using kalk for my 80 gal system that i am currently running. My only actual question is what is the saturation of kalk? I found on the web 1.73g/L of RODI at 70F. I never fact checked this with literature or you. Is this the correct saturation level?

Anyways I am in the stages of planning a 240 gallon system now. For the 240 system I am leaning towards a Ca RX but still dose a bit of kalk for pH stability. I feel that a Ca RX does free up other elements that are vital for coral growth. I just sent out my water for ICP testing via Trition. I am expecting to find major deficiencies in my trace elements since kalk doesnt supply any. I have been eyeing up going with the Ca RX and dosing Red Sea's trace elements. The triton method is waaaaay too expensive for me. Plus I dont agree that water changes are not needed. At some point there has to be some untested stuff that builds up. So my thoughts are small water changes (5% every other week) Ca RX, and trace dosing.....if you have any opinions they would be welcome!!!

Thanks

The exact saturation level will depend on temp, but at 25 deg C is 0.0204 M, or 1.51 g/L. This is known in the literature and is used as a pH standard for high pH solutions. More dissolves at lower temps and your quoted value may also be correct.

https://pdfs.semanticscholar.org/45c8/c706731288472fdad035617ea93caf696215.pdf

In terms of water changes and such, here's a copy and paste from another recent thread where folks were asked what method they'd use if they were starting over. here's what I wrote:

In terms of water chemistry maintenance, I'd maintain calcium and alkalinity with limewater (maybe pH limited to pH 8.55 or less to prevent overdose; probably on dosing timer rather than ATO) and a two part (if needed; maybe also pH limited to pH 8.55 or less). I'd like a continuous alk monitor, and if Mindstream comes on line, I'd monitor ammonia 24/7 and in different system location (main tank, exit from refugium, etc.) for interests sake.

There are some ions I would dose essentially independent of measurement because I don't think measurement is particularly useful for them (e.g., iron because it is typically below detection limits; silicate because it depletes so fast).

There are a bunch of ions that I do not consider important at the levels reefers typically have (e.g., lithium, maybe barium, I'd need to think through this list) and I would make no effort to control those either by export or by dosing.

I would likely experiment on the tank over time to re-verify for myself that my longstanding opinions on certain chemicals are not useful if dosed to maintain natural levels, despite the fact that many reefers do. If they showed a positive effect, I'd rethink dosing them. These include iodide and strontium.

There are a whole bunch of biologically active trace elements that I'd likely measure and dose which I did not in the past, but which also tested low (e.g., molybdenum) and I'd likely dose these to roughly NSW levels. I might experiment on these in a variety of ways (e.g., allowing one to go undosed for a long time and then restart and see if anything apparently changed).

I'd probably do automatic water changes, but again, might also experiment on the amount, from none to a couple of percent a day.

As to other "methods", I'd likely do some or most of these that I partly copied from Ashish's post:

Ato
Temperature control (temp controller to kick on heaters or cooling system)
Skimmer
Rodi unit with inline tds
Nutrient export (macroalgae, gfo, organic carbon dosing, GAC, maybe experiment with organic resins like Purigen)
Might try LED lights to save electricity, but I'm not yet convinced I'd like the look

 

[Lousybreed]

Great info. Thank you. I am divided on my decision for alk and Ca addition. I am almost evaporation limited on kalk already. I dose kalk rather than ATO because evaporation rates change too much throughout the year. I am only using about 2 gallons a week of RODI compared to 12 gallons of kalk. I am going to keep researching trace element addition for the tank. I will probably settle on a hybrid system, Ca RX and kalk or 2 part and Ca RX. I am also interested in how my big fuge uses trace elements. We will find out soon when I get my ICP results.