Strontium nitrate addition

[LouCiro]

In 1991 Klostermann published an article in FAMA on "Phosphorus in the Marine Aquarium" where he recommended Strontium addition to eliminate phosphorus. Has anyone used this? I have used lanthanum Chloride and had problems with large tangs going belly up. They revived when placed into a tank with no Lanthanum. It seemed like a threshold was reached where phosphates were lowered and then suddenly the lanthanum became toxic. I am working with a 3000 gallon system and working on cyano removal and phosphorus reduction. Currently Ca++ = 390-420, temp = 77.7, Alk= 2.95-3.01, Po4= 0.08-0.14, ORP= 392-408. We change 400 gallons/ week and are increasing to 1000 gallons/week of fresh salt mix, Instant Ocean. We use some Iron removal and some Kalkwasser. Feed is primarily Zeigler pellets. Mix of corals and fish. Any suggestions for improvement. I am looking at building a anerobic bacterial column to reduce phosphate. Any articles on designs, calculations etc ? Thanks for the help.
Lou

 

[Uncle99]

From a marine tank perspective, that PO4 at 0.08-.14ppm is pretty normal IMM.
Why is it you want to reduce that number?

 

[Randy Holmes-Farley]

IMO, simple strontium dosing is not a good way to precipitate phosphorus and I think it is doomed to fail. It is not insoluble enough to do anything useful unless strontium is raised quite high.

Could one use it in a complex system like they did, raising the pH way up? Seems far fetched to me. Magnesium hydroxide will be precipitating at elevated pH.

They also di not verify if strontium is rising, just asserted it won't.

 

[Randy Holmes-Farley]

FWIW, I do not think that author has a strong understanding of solubility chemistry.

if you look up the solubility (by KsP) of CaHPO4 and SrHPO4, you find that SrHPO4 is actually more soluble (not less).

The Ksp of CaHPO4 is claimed to be 1 x 10-7

Ksp Table

KsP of SrHPO4 is claimed to be 4 x 10-7

https://acsess.onlinelibrary.wiley.com/doi/abs/10.2136/sssaj1962.03615995002600010013x

Thus, there's no scenario where one would precipitate SrHPO4 from solution, as the authors claim, without raising the normal strontium concentration in seawater (8 mg/L) to far above the normal calcium concentration of 420 mg/L.

 

[LouCiro]

Thank you for the replies. We are seeing a strong growth of red cyano in main 3000 gallon tank and are exploring ideas to improve the conditions. We also have a 120 g tank on the same system that gets much less light. The main tank gets sunlight most of the day. The small tank has many soft corals
and little cyano. We also think it gets more blue spectrum light. We are going to change out the large system LED s to more blue as an experiment. Any other ideas for improvement?
Thanks,
Lou

 

[marke]

antibiotics---e myacin

 

[blasterman]

I've fiddled with strontium dosing. Nothing heavy, but it had zero affect on corals and did nothing with phosphate.

Convinced its just taken up by coral skeletons because it looks like calcium.