What causes SPS to lighten/bleach

[Wiskey]

NO3 is probably up from all the rock basting.

I'm encuraged to see the CA and Alk down,.. that means something is taking it up Plus, with all the water changes, and ALK of IO coming in so high, something is taking it up even faster than it looks.

Whiskey

[tdwyatt]

Amy, remember that longterm use of 2 part additives slowly drops over time the percentage of Mg++ in your ASW, even if your S=35. This is due to the accumulation of sodium and chloride from the parts of the two part additives that don't get used to make CaCO3... This may mean that you need to do some high percentage water changes to bring up ALL of your conservative elements of seawater rather than just supplement your Mg++...

[YLChik]

I have been changing out 5 gallons a day since Dec 1.

My rock seems to be shedding some very gross black stuff. YUCK!

Tom will daily water changes do the same thing, or should I plan on 1 larger change?

[tdwyatt]

Originally Posted by YLChik

I have been changing out 5 gallons a day since Dec 1.

My rock seems to be shedding some very gross black stuff. YUCK!

Tom will daily water changes do the same thing, or should I plan on 1 larger change?

Gradual small changes can make a difference, but you'll need to do several large percentage water changes to really impact the water column and see a true correction of this situation. If not, 5% of a dilutional change over a long period of time really just muddle the situation more as time goes by. Suppose you had 100 gms of a substance you were trying to remove by dilution with a 5% water change once a dy and there were no incoming sources of this substance (an example for illustration purposes)... 5% of 100gm=95gm remaining after the first change, then 5% of 95%=90.25gm after the second change, then 5% of 90.25=85.73gm, then 5% of 85.7375=81.45~, yadda yadda yadda... Vs 50% change of the water of 100gms = 50gms after the first change, and 50% of 50gms = 25gms, then 50% of 25 gm = 12.5, etc. you get the picture. The same is true when replacing upscale using aliquots of fluids). Not only is using larger amounts quicker, but the aliquot losses do not leave the accumulated fractions gathering to further skew your total numbers.

Personally, I would consider a few 80+% changes with well-matched pH, alk, ca, temp, salinity, etc. numbers to correct the situation (four at least at somewhere in the 90-95% range), then maintain with 5-10% changes once q 2 weeks for the next year, then repeat, using your Mg numbers to follow just how skewed the overall proportionality of your conservative elements has become during the year, ESPECIALLY IF YOU CONTINUE TO USE 2 PART SUPPLEMENTS AS YOUR PRIMARY MEANS OF SUPPLEMENTING CALCIUM AND AKALINITY.

There is nothing wrong with using 2-part supplements, it's just that you need to indirectly monitor how much extra NaCl ends up in the tank by continuously monitoring your Mg levels in the tank and your salinity (which will gradually increase over time using 2 part additives for Ca++ and alk unless you remove a portion of the water column on a regular basis and dilute what is left with RO/DI or distilled water). I avoid this issue by using a balaned additive, either Kalkwasser when making water changes ASW or as the CO2-driven Calcium reactor for tank suplementation. This creates calcium ions and carbonate/bicarbonate ions without the need for the intermediate dry crystals of calcium chloride (CaCl2) to make the calcium chloride solution or sodium bicarbonate (NaHCO3) to make the alkalinity solution of the generic 2-part supplements. Obviously the Ca++ and HCO3-- make the CaCO3 plus a proton (H+), which the corals and the Corallinaceae use hermatypically. however, when we use the two part additives for supplements, for every mole of CaCO3 that is biologically (or abiotically for that matter) precipitated out as skeleton (or precipitate on heaters, pump impellers, etc.), we end up with a mole of NaCl that is increasing its percentage in the water column, gradually over time decreasing the percentage proportions of all the rest of the conservative elements that make up your salinity... This salinity increase will occur in spite of maintining your system's total volume with automatic top off devices.

I hope the rational for this is clear, post q's if it is not.


HTH

[YLChik]

Tom, I just took sudafed...

I got the bit about large water changes in succession being more benifical, dilutes nasties faster and corrects imbalances faster as well.


once ya got into the calicum /alk bit and preciptation you lost me. Can you try again with Kindergarten words? I think what I understood is that dosing 2 part like I am leaves some portions of those elements unused which ends up in the water column... one of the unused parts is salt ( Nacl2) and that raises the sg of my tank over time. To deal with that I need to keep up with 5-10 % water changes every 2 weeks and may need to add ro/di water in addition to my top off water to keep my sg level.

[tdwyatt]

Originally Posted by YLChik

...one of the unused parts is salt ( Nacl2) and that raises the sg of my tank over time. To deal with that I need to keep up with 5-10 % water changes every 2 weeks and may need to add ro/di water in addition to my top off water to keep my sg level.

well, kinda...

2-part calcium and alkalinity additives almost always are made of a solution of calcium chloride (CaCL2) for the calcium part, and a separate solution of sodium bicarbonate (baking soda or NaHCO3) to supplement alkalinity. At first glance, you'd think that we should just be able to mix them together in one bottle rather than two and be done, but this results in a huge precipatory event where the calcium and carbonate ions in the presence of each other preferentially react to form calcium carbonate, and at concentrations that are MUCH higher than the solubility of this very insoluble salt: it would form one big white brick! It is this very concept that allows corals to biologically concentrate bicarbonate and calcium ions from seawater into the calcioblastic endothelium location between the coral tissue and old skeleton to precipitate at the desmosomes* to make new skeleton. It is this process that uses up the calcium and the bicarbonate part of the additives from our seawater column, but there is nothing in our tanks to use up or consume the sodium and the chloride these solutions also contain. Since sodium and chloride are very soluble in water, they accumulate in their dissolved/ionic form, and begin to make up a greater portion of the specific gravity in seawater used to determine salinity (grams of salts per milliliter solution).

Seawater is a very unique solution in that 75% of the Earth is covered by seawater as ocean, and although the salinity may vary from location to location (the actual number of grams of the salt mixture samples contain per milliliter solution at a particular location), the proportion of the different salts that make up that seawater is in a fixed proportion, regardless of the location from which it was taken. This tennet of chemical oceanography is known as the conservative nature of the proportionality of seawater, or the first law of chemical oceanography**.

Originally Posted by Dana Kester

...all the species of seawater contain the same ingredients all over the world, these being very nerly the same proportion to each other, so that they differ only as to the total amount of their saline contents...

Continued use of 2 part additives over time becomes much like adding spoon after spoon of sugar to a glass of tea with lemon: if you add 15 teaspoons of sugar to your glass, it gets so sweet that you have to pour out the syrupy solution and add some unsweetened tea back to it to make it drinkable, but by the time you've diluted it down to drinkable, you've poured out allmost all the lemon flavoring. You're doing the same when you use a two part solution: the added solute is NaCl instead of sugar, the intensity of our solute is salinity rather than sweetness, the conservative elements like Mg, K, SO4, etc. are the lemon flavoring, and the water content of the sample is the unsweetened tea. In order for us to bring our salinity back to 35 PPT (or a SG of around 1.026 @ 80^oF ), we must first "pour out" (remove a gallon or so) some of our ASW, but in doing so, we remove not only the sodium and chloride, but also the balance of the conservative elements (our lemon squeeze) dissolved in that sample. Then we must dilute what is left in the tank with some RO/DI (pouring back in some of the UNSWEETENED TEA to reduce the sweetness) which then dilutes all the salts to bring our SG back to normal. Although the total salinity is now correct, it is no longer a sample representative of seawater, because we have reduced how much total conservative elements we have in the sample, but increased the proportional amount of both sodium and chloride in the sample (the part of the 2-part additive left behind ith each adition of 2 part solutions). This becomes a vicious cycle over time, and will accumulate to the point that all that is left in terms of our original mix of seawawter is a salt water brine of sodium chloride. It may be at the right concentration (35 PPT salinity), but will no longer contain the mix of the right amounts of our list of conservative elements. We can measure this effect by measuring how much Mg++ we have in a given sample, and although we could just add some Mg additive, we would then lose a means of measuring (albeit indirectly) how far off our mix is from the ideal ASW mix based on how much Mg we have as compared to how much we should have.



Is this any clearer for you?








* http://www.fiu.edu/~goldberg/2001b.pdf

**coined by Dana Kester

[YLChik]

Tom, I will need to read that over a few more times, but I think I understand a little more... do me a favor, DON"T teach kindergarten

What is it you DO do for a living?

[YLChik]

cal 360
dkh 6.4
sg 1.026
ph 8.3
temp 76.9

[tdwyatt]

Originally Posted by YLChik

What is it you DO do for a living?

I teach Kindergarden...

[YLChik]

funny funny guy

[YLChik]

kinda using this as a log now...

I am seeing better PE and I am sucking WAY less junk off the sand bed... granted I stopped up the kitchen sink with all the sand and my husband is THRILLED about that let me tell you

changed 25 gallons on Sunday - THAT was a chore, but REALLY good for the tank.

sg 1.024
temp 79.5
cal 400
dkh 7.0

[tdwyatt]

Originally Posted by YLChik

kinda using this as a log now...

I am seeing better PE and I am sucking WAY less junk off the sand bed... granted I stopped up the kitchen sink with all the sand and my husband is ... ...changed 25 gallons on Sunday - ...REALLY good for the tank.

sg 1.024
temp 79.5
cal 400
dkh 7.0

So what all is different that you're doing now?

Boost your alk just a bit, shoot for 9-ish dKH alkalinity at 400 PPM calcium, bring your SG up to 1.026 at 80^oF for S=35 PPT. How are you supplementing your calcium and alkalinity? Do you have a DSB?

[YLChik]

all the water changes and returning to blowing rocks off

changed carbon out
changed flow to a better through the rock pattern
cleaned off bulbs

I adjust dkh to 9 and cal to 425
driveway heat cacl2 and baking soda
i lowered sg since the dosing has been rasing sg - i figured it would give me a buffer instead of driving it too high

no dsb - 2-3 in of sand