lanthanum chloride dosing

jelly · Dec 1, 2017

I been reading about dosing lanthanum for lower po4. I understand most of it in using a 10 or 5 micron bag and dosing it slowly and dont drop it more then 3ppm per day. So like I said I understand most of it. The area I have trouble with is how much to use In a 1000ml iv bag. I have read 3mls for a 1000ml bag and read others. Is the amount of lanthanum chloride used determined on the amount of water volume and amount of po4? If there isn't a set amount to use it is just something that needs to played with to find the right amount to use to drop po4 down by 3ppm per day until close to 0. And once close to 0 is achieved then finding a maintenance dose to maintain it there?

Second question. My buddy has several tanks and he wants to use lanthanum chloride. He was told to use a 10 or 5 micron bag but to just dose the 3mls right to the bag in a full dose and not drip it. Y is dripping a better method so I can explain it better by him.

Randy Holmes-Farley · Dec 1, 2017

jelly said:
I been reading about dosing lanthanum for lower po4. I understand most of it in using a 10 or 5 micron bag and dosing it slowly and dont drop it more then 3ppm per day.

3 ppm per day? Typo?

How high is yours?

jelly · Dec 3, 2017

.03 I ment

Randy Holmes-Farley · Dec 4, 2017

To some extent the dose is figured by trial and error. It does not just precipitate phosphate, but likely carbonate and maybe other things, so the relative amounts of these in the water may impact the required dose.

In a perfect world where only lanthanum phosphate precipitated, adding 1 gram of anhydrous lanthanum chloride solid (containing 0.56 g lanthanum) to 100 gallons of aquarium water with sufficient phosphate could remove 0.39 grams of phosphate, or 390 mg/379 L = 1.03 mg/l.

TMB · Dec 4, 2017

The "safe" dose that I have been using is 6 ml SeaKlear LC to 1000 ml RODI for every 300 gallons of tank volume. For smaller tank volumes divide everything appropriately.

As Randy stated above the reduction of PO4 depends on several factors (most of which are above my head, I'm no chemist). In order to safely dose LC you need to have a reliable way to measure PO4 before and after dosing. The reason for this is that LC is not good at reducing PO4 below ~.04 in my experience. When the PO4 gets too low the LC seems to stop reacting and begins to cloud the water. This tells me the reaction is becoming inefficient, and I do not try to get lower than .04 with LC for safety reasons.

As far as dripping vs. "dumping it in" I would only drip it slowly into the overflow - which in turn needs to be draining to the 5-10 micron bag. I drip the diluted solution at a rate of about 1 drop per second. So dosing 1000 ml takes several hours.

One more thing, you need to keep an eye on ALK when dosing LC, as it tends to lower it in the process.

I don't have anything but my experience dosing LC (weekly for the last year or so) to back up my assertions, but this process has worked well for me. Hope this helps

TMB