[LongShot]

I've been using the 2-part calcium/alkalinity supplement from ESV for awhile now, and although I'm pleased with the results (Ca = 400 ppm, dKH = 9.2), I've noticed that the stuff seems to have a transient effect on my salinity. I normally run a Sp.G. of 1.024, but if I check it right after dosing with the B-Ionic, it goes to 1.026. After a few hours, the Sp.G. settles back down to the usual 1.024.

Is this common with B-Ionic? Is it something I should concerned about? All the tank inhabitants look fine. I'm dosing at the rate of 15 ml of each component in a 65 gallon tank with about 75 lbs of LR. in it.

Thanks,
Bert

 

[Toadfish]

Try dosing through your sump.

 

[LongShot]

I have been dosing through the sump and taking samples for Sp.G. measurement from the main tank. Just for grins, I did try dosing in the main tank and saw the same effect.

Regards,
Bert

 

[bamann345]

What are you useing to measure the SG?

 

[LongShot]

A lab grade floating hydrometer used in a graduated cylinder. It isn't NIST certified or any thing., and may not be "dead-nuts" accurate. But it is precise enough that I believe these patterns I'm seeing are real.

Seems to me I read somewhere (can't remeber the source just now) that increases in salinity can happen with B-Ionic, but this sort of transient change puzzles me.

Regards,
Bert

 

[tdwyatt]

I've been using the 2-part calcium/alkalinity supplement from ESV for awhile now, and although I'm pleased with the results (Ca = 400 ppm, dKH = 9.2), I've noticed that the stuff seems to have a transient effect on my salinity...

hey Bert, welcome to TRT, a few related threads to start with:

SG and salinity effect on alkalinity and reated readings

and a seemingly unrelated thread that brings the meat of this thread to the table in the last few posts.

The last few posts in the second thread have links to Dr. Bingman's Aquarium Frontiers articles that fully discuss the effect listed here. The 2 part additives are for the most part, Calcium Chloride solution in one bottle, and Sodium bicarbonate/carbonate solution in the second bottle, usually in equimolar proportions per volume dose. Our corals use the Calcium and the alkalinity part of these solutions, leaving behind... SODIUM AND CHLORIDE. Over time, these elements build up in the water column, skewing the proportion of conservative elements in favor of a sodium chloride brine. This occurs as we test for SG and remove some of the water from the system to "drop" the salinity. We continue to add the 2 part additives, more sodium comes in, more chloride comes in, and the proportion of sodium and chloride in relation to the other elements slowly seesaws up until the next adjustment, and so on, untill the SG of the tank may totally depend on Sodium and Chloride alone, barely resembling seawater in any form.

This occurs more rapidly in systems that do not have regular 10% water changes, but will occur nonetheless in all systems that use 2 part additives as we know them now. Craig suggested at the last Louisville MACNA meeting (1999 I think) that folks that use such a Ca/Alk regimen perform regular 10% water changes every week to two weeks, and large water changes (on the scale of 50%) approximately once a year to reestablish the proportionality of the conservative elements.

HTH

 

[tdwyatt]

...Seems to me I read somewhere (can't remeber the source just now) that increases in salinity can happen with B-Ionic, but this sort of transient change puzzles me...

A compartmental dilutional phenomenon, it takes some time for the nascent NaCl to be fully diluted in multicompartmental systems. If you have a sump, it will have a dilution time in that system and another dilution time in the water above the sand bed, another in the interstitial water of the sand bed, and finally, the water contained in the live rock (even the biological compartments have a role in this). The time that it takes for the newly added/formed sodium chloride to diffuse to completion is a function of the total volume of distribution for each compartment per unit of distribution time as it is affected by the rate of diffusion from one compartment to the next. Sump to tank water is the fastest, tank water to the rock would (I think) be the slowest. The amount of time involved with reaching Vdmax would be totally dependent on the number of compartments, the volume of distribution (Vd) in each compartment, and the rates that the sodium and chloride take to reach equilibrium. Although it may appear that the salinity slowly goes back to "normal", in actuality, each time this addition occurs, the level of salinity goes back to a slightly more saline level.

Interesting math in calculating the rates of distribution, Le Chatelier would be proud!

 

[Casey]

whoooo Tom let me ask ya have you ever given a easy anwser

 

[tdwyatt]

whoooo Tom let me ask ya have you ever given a easy anwser???

YUP!

 

[LongShot]

While Tom's answer might not be the, uhhh, most concise, it is certainly the most complete. Thanks Tom!!

Having spent a good many years as a health care practitioner, I have some understanding of compartmental dilution between intracelular, extracellular and interstitial components of human fluid and electrolyte balance, and such a phenomena in a captive reef system would certainly explain my observations. I just never thought of it in that context. Glad to know I'm not losing my marbles after all.

The bottom line is I'm doing 20% water changes weekly right now, so maybe I'll be OK in the long run. Or maybe I'll just go back to the drudgery of mixing up and dosing Kalk. Ugh!

Again, thanx....
Bert

 

[Casey]

Bert I know I was just teasing him