Weird issue while dosing Lanthanum Chloride...

jherrin215

jherrin215

GO COLTS!!
I have been reading up on phosphate control and decided to give this method a shot to initially bring down my ridicoulous phosphate levels then switching back to mainly GFO with a supplement of lanthanum when needed. I dosed for the first time today. My phosphates were around .5ppm using a standard test kit so I figured up that I needed to dose 1.5 ml to remove this amount with my roughly 220 gallon system volume. I mixed up 1 ml of phos-free in about a quart of water. I slowly (4 hours) dripped this into a 5 micron filter sock right at the inlet of my skimmer. Once I saw that everything was going smoothly I went ahead and laid down to take my nap where I worked last night. Whenever I got up from my nap the jug was almost empty but I noticed I didn't have any skimmer head. Almost everything that I have read talks about how dosing lanthanum makes everyones skimmers go crazy and skim really wet for a while. Mine quit. There was still water flowing through the skimmer but it almost seemed like the flow was lower than normal. I even pulled the venturi line off of the gate valve and let it get a full flow of air. It still didn't make any bubbles. I just emptied my skimmer cup right before dosing and bubble level was normal. I made no adjustments to the skimmer before dosing. I pulled the feed pump (Mag 9.5) off and am currently letting it run in vinegar water, which needed to be done anyway, to ensure that it wasn't stopped up. It seems to have plenty of flow. I am wondering if this is just a fluke coincidence or if the dosing had something to do with my skimmer stopping. I am fixing to remove the ventrui valve to ensure that nothing is blocking the suction hole but wanted to get the opinions of the gurus. Thanks in advance for any suggestions.
 
Many hobbyists add the lanthanum chloride so that it next enters the skimmer & have not reported skimmer problems. I would think the 5 micron filter sock would do a better job at removing the precipitants provided you provide ample time for the precipitants to form before the filter. Any lanthanum chloride that passes through the filter may precipitate out in the tank water, which can be collected by the skimmer. I don't see why it would cause a decrease in skimming.

That said, the lanthanum chloride will reduce your alkalinity, so keep an eye on it. ;)
 
If a lot of it made it through the filter before it reacted, you might build up Lanthanum Carbonate inside the pump. I wouldn't think it would be a problem but if the pump already needed a cleaning it might have pushed it over the edge.
 
I found the problem with my skimmer, had a vertimid snail blocking the venturi hole, guess it was weird coincidence. Oh well, skimmer needed a good cleaning any way. I did notice something that concerned me though. I now have a lot of precipitation at the bottom of my skimmer section of my sump. I dripped it slowly and made sure the filter sock was not overflowing. Not sure how all this made it out. It seems to all be trapped and I am going to do a wc to remove it but still not sure why it happened.
 
When you dose, you say the filter sock is submerged some and near the inlet of your skimmer. Do you have water flowing inside the sock from a separate pump? The sock should gunk up to the point where it is overflowing. If you drip into the sock without a water source in, I'd suspect there isn't enough po4 water to bind to the LC. Recommend you change that to have water flowing into the sock from either the return, a separate small pump, or even your skimmer output. I have my GFO reactor output going to the sock when I drip (usually before a water change). I've also never observed any sediment.... but that's just me. Good luck
 
Oops didn't motion that. The sock is over my overflow line feeding the sump. Right next to the skimmer inlet. The only thing I can figure is that the sock I got isn't really 5 Micron. It's brand new though, i ordered 5 micron and it feels kinda denser than my 100 micron socks.
 
iI didn't really notice the sock gunk up at all, its like all the lanthanum reacted in the skimmer chamber, not in the sock.
 
As noted the precipitating lanthaum phosphate and/lanthanum carbonate coud clog the pump or the venturi. The later will cause the skimmer to run with less air and more water thus less foam.
 
The problem with the skimmer was a vermetid snail. Now I just can't figure out why I had so much precipitate using a 5 micron sock
 
If you are getting precipitation after the filter, than either the lanthanum chloride is passing through the filter since it has not had enough time to mix in the water or your filter has too large a pore size. You can't see particle much smaller than 60 microns in size, unless massed together.
 
These were big chunks, probably 1-2 mm each. It had to get through the filter before reacting, but I don't know why. Could it possibly be too much flow through the sock?

Sent from my HTC
 
That would probably work fine, but I've read of many people using this method, so I think the method is fine, but something in my execution was off.
 
Ok, now its even more weird. I changed out the sock before you original post yesterday, completely cleaned out the skimmer section of my sump. Went back today and there is another pile of white precipitate. Looks about like a 1/4 cup of sugar on the bottom of the sump??? I have no clue now. And I have not dosed anymore lanthanum.
 
I'd guess (but only guess) that you're seeing more lanthanum phosphate that's settled or been moved around by pumps. I wouldn't worry too much, but I would reduce the flow through the socket for the next round of dosing.
 
It sounds like you're dosing to much to fast.

If you're dosing more lanthanum than can react with the volume of water in the sock it's going to pass through the sock precipitate in the sump
 
Ok Jonathan, i'll dial back that overflow some to see if that helps any before I dose next. As far as my phosphate level, I'm still showing around 0.25
 
Where is your point of entry (LaCl that is). Is it further upstream, say at your DT overflow; or are you dripping the LaCl right into the sock. Could be that the drain flow is so fast that there's no time for the reaction to take place within the sock prior to all of the LaCl washing through unreacted.... I think this could cause the same problem you're experiencing. In other words you might have to allow more opportunity for the reaction to take place prior to exiting your sock.

Sheldon
 
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