Hi Steve,
Sorry my bad. Guess I engaged fingers before brain was fully functioning from the coffee this morning. LoL
I have not observed this in my system with the Purple and Yellow Tangs but I dose small amounts of high purity Foz Down frequently, have a consistently low Phosphate level and don't have an old Scopas Tang. Here is the article to which you may be referring to.
http://www.beananimal.com/articles/l...and-tangs.aspx
Some things I noticed about the article.
1. A small tank of 75 gallons.
2. Most likely using the highly concentrated pool version as they dosed 1ml/day.
2. Only the Scopas Tang was affected
3. It looked like it had been in a fight with another tang and then developed a secondary bacterial infection.
4. After massive water change the fish begins to improve.
5. Lanthanum dosing stopped.
My questions are? Was it the massive water change that helped the fish get better or was it the discontinuing Lanthanum dosing? Did the whole episode have anything to do with Lanthanum at all? The author makes it quite clear that it is anecdotal info.
There are a lot of public aquariums that rely on Lanthanum to control phosphate in their displays. Some use sand filters to remove flocks but I doubt it catches all of them or any non reacted Lanthanum.
As for the SPS I have some fairly sensitive species such as Echinata and they are fine. I will be doing pics today so can take one of the Echinata.
I have not observed this at all and I have both acrylic and glass tanks in the system. In the tank where I removed a lot of Phosphate(1400mg/l) I did not notice this either. I removed the Phosphate over a period of 2 weeks.
Here is the article that talks about the precipitation and SPS issues.
http://www.coralmagazine-us.com/cont...ling-phosphate
It must be noted that Daniel removed 1.3mg/l in a couple of days. Here is the quote from the article "They were adapted to a phosphate concentration of 1.6 mg/l, and in consequence grew slowly, and it seems that when this concentration dropped to 0.3 mg/l within a few days as a result of the drastic treatment, the complex physiological processes that take place in these corals were thrown out of balance."
From both of these old articles one can deduce that:
1. Lanthanum may or may not affect old Scopas Tangs.
2. Don't use too much too fast as you will shock corals and may cause precipitates to form.
The ideal best practice may be to dose the Lanthanum in a separate tank and trickle the water through it as you suggested. Next best would to slowly add diluted Foz Down into a 5-10 micron sock and have a small pump pumping water from sump through it. At the end of things we may or may not find that the precautions were necessary. It is up to the hobbyist how they want to operate their reef tanks. It has been over 6 years since people have started using Lanthanum in their tanks. If there was an issue one would think it would be all over the internet. Just my Timbits. ;-)
Cheers,
Tim