This is a huge observation... You ran all those sorbant materials as well as performed massive water changes and your Tin doubled? Am I reading that correctly?
If I perform a simple conceptual mass balance on Tin this scenario suggests to me that 1) possibly your RODI water is massively contaminated, 2) one or more of those sorbant materials leached Tin into your system, or 3) you have a different independent source providing an ongoing addition of Tin that's increasing over time (18, 22, 45ppb).
I doubt it's #'s 1 or 2. Have you inspected your system for corroding metal items? Hinges, screws, nails, impeller shafts, clips, knobs, filter sock rings - anything metal whatsoever. Corrosion of metal is a process that starts slowly and then increases with time. However, leaching of Tin from glass and plastics decreases over time. It's plausible to me that our calcium carbonate rocks may adsorb Tin - but even if they did they wouldn't release what they stored to a level twice (45) what it was before (22) after a massive water change with presumably 0ppb Tin. That's not how adsorption equilibrium works.
Yes, despite all those products being used AND massive water changes, the Sn level increased. (The following is a little more accurate compared to what I wrote yesterday. Sorry I rushed a little last night):
5/11/20--Triton ICP:
Sn = 18 (set pt is 0.1) I then performed 4 water changes over the next 5 days: 25%, 30%, 30%, 30% which should have brought the level to about 4.8. I then used TLF Metasorb for 5 days (placed in sump mesh sock so had good water flow on/thru it). I then performed another 20% water change, so even if the Metasorb did nothing, the level should have been around
3.9. On
6/1, I sent water to Triton and ATI. Triton showed
22 and ATI showed
45.84 (set point is 0.47 for ATI) (when I was expecting < 3.9).
Next......After 8 days of a combination of Polyfilters, Seachem Cuprisorb, MetaSorb, carbon and Power Cleanse (3 days)…..and enough water changes to lower the tin from 22 (Triton) to about 8.5 (even if other products didn’t work)….the ICP showed the tin at
18 (Triton) on 6/22.
RO/DI, RODI holding tank, and salt mixing tank were all confirmed, more than once, to be free of tin.
Now it was time to disassemble my tank and I started testing "components" individually or in groups, in separate tanks. (ATI was used for all tests to follow since they run 2 samples per kit). These "trials" included:
-
GROUP "A" (first set of "trials"; "soaked" for 5 days before sampling):
A-1. Live Rock Tank. 25 lbs of live rock and all livestock (fish), including 30+ SPS frags were moved to a 29 gal tank for the duration of "trials".
Sn = 13.73
A-2. Artificial Rock. 40 lbs soaked in new saltwater; aerated).
Sn=30.55
A-3. Hang-on Algae filter. Run on 10 gal tank.
Sn=N.n.
A-4. Sump (of Red Sea Reefer 170; also contained GHL probes, magnets and ATO apparatus) after thorough cleaning with RO/DI and filled with new saltwater.
Sn= N.n.
A-5. Main tank (after similar cleaning as sump)
Sn=7.61
A-6. Misc Tank "A": In a plastic storage container, I ran the protein skimmer and soaked the main pump, Echotech pumps, pvc pipes and misc pvc items, magnets, etc.
Sn=201.3
A-7. Kalk water (from reactor) and
ATO water run thru GHL doser (50:50 mix):
Sn=125.1
A-8 New Saltwater (80% TM + 20% IO);
Sn=25.53
The
A-8 value is very disturbing because this is the water that was used in all the tests above (except A-7) so how can Sn in A-3 and A-4 be "undetectable"? I'm forced to temporarily ignore this value and look at the extremely elevated values in A-6 and A-7.
Next batch of tests, GROUP "B" (to further explore A-6 and A-7):
B-1-New salt mix (used in these Group B trials; TM only)
Sn=N.n
B-2 Main pump (I took the pump from A-6 above so I could see if I can use it when I start up main system again):
Sn=N.n
B-3 Misc Tank "B"- I took only the skimmer (minus its pump) and Red Sea pipes/tube from Group A and tested them olone, this time in the 10 gal glass tank from A-3 (shown to be N.n.). I was concerned that the high Sn in A-6 may have come from the plastic tub.
Sn=199.0
B-4 Kalk water (this time I eliminated the ATO water and all tubing from A-7 and just sampled water directly out of the Kalk reactor.
Sn=150.3
From GROUP B it appears that there are 2 independent sources of the tin (B-3 and B-4).
This is why I set up Group "C" (Results pending for this group--8/13). (C-1 and C-2 will narrow down B-3; and, C-3 and C-4 will narrow down B-4)
C-1 Skimmer (soaked in 10 gal glass tank)
C-2 Plumbing from Red Sea Reefer (Sched 80 pipes and green plastic hose)
C-3 Kalkwasser (newly mixed kalk in RO/DI)
C-4 Kalk reactor. (Reactor was flushed with garden hose, towel dried, rinsed with RO/DI, dried; then filled with RO/DI and allowed to sit for 5 days.
MISC COMMENTS:
-I seriously doubt that there is metal causing the problem, being that no other metal was elevated on the ICP tests, everything was brand new 7 months ago, and since I "broke down" the system, it was easy to look for metal. Also, the results tend to suggest otherwise.
-I know a lot of people say "don't worry about tin" and/or "take ICP results with a grain of salt". I agree that one should not jump to conclusions from just one elevated element from a single test. But with all the "positive" values I have gotten, it has to be significant. And, yes, I do believe that my SPS are being affected.
-I think glass as a source can be ruled out given the results above. (The slight level of Sn in A-5 could be from leftover water I didn't get out when I cleaned the tank, or possibly from Sn that was adsorbed and released by the plastic overflow box. In any case the relative low value of 7.6 compared to the 150-200 values makes me put the "glass idea" on the back-burner for now.)
-I'm fairly convinced that rock can adsorb AND release tin. This would make sense and may explain A-1 and A-2. (We know rock can do that with phosphates and copper, so why not with tin?)
-I'm very curious to see if the tin sources are the two acrylic/plastic reactors: skimmer (from B-3) and kalk reactor (from B-4). (I don't want to mention brand names at this time but I think they are made by the same mother company; both purchased in 12/19).
Anybody still following this??
I just jokingly told my wife that "Everybody is going to think I'm crazy!" Her reply of "They're not the only one" was not much appreciated! :) So.....do you guys agree with her or do you think I'm 'on to something'?