What is this white foamy stuff in my sump?

[Joe31415]

It looked like a white fluffy sponge, until there was any movement near it, then it looked like the white precipitate you see when you dose alkalinity. If it was just a little bit I'd just assume that's all it was. However, it was *a lot* and you can see the white tube with the 90 deg connector on it. That's the tube for the alk doser (and calc and RODI) which goes directly into the return pump.
The only things I can think of are:
-That tube has a whole mess of splitters, connectors, check valves on it. A few days ago there was a clog so I pulled it all out to clean it. I know I saw some alk coming out of it while I was messing around with it. But it appeared to be just the little bit left in the last few inches of that tubing.
-Earlier in the day, I had measured the alk at 7.8 and dosed more. I supposed it's possible the dosing pump went overboard, but the alk reservoir doesn't look all that much lower than it was the last time I looked at it. When I checked it, I was worried the entire thing was going to be empty. Also, I'd be surprised if (or maybe I am surprised that) I could have an alk of 7.8 with a giant pile of it sitting there. Surely a lot made it into the tank if that much settled out.

Also, I had, just a few hours earlier (just before I dosed it) pulled samples for an ICP test. I pulled them right from that section of the sump. I'm pretty confident I would have noticed if that was there when I was doing that.

Now, this all happened late last night. I removed just about all of it other than what got kicked up in the process. I wanted to let it settle and mix with the rest of the water before retesting alk, but I fell asleep and forgot about it until now. I'll test it later today when I'm home. It'll be interesting to see if it's still in the 8ish range or if it skyrocketed.

So is it alk? Is it something else? I have no idea.

.
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One other thing I can think of. I hadn't been doing water changes for the past few days in either of my tanks. Last night I decided to do change a few gallons and the new water is pumped into that general idea. I suppose it could be from that, but I've never seen fresh salt water do anything like that.

 

[MnFish1]

It looked like a white fluffy sponge, until there was any movement near it, then it looked like the white precipitate you see when you dose alkalinity. If it was just a little bit I'd just assume that's all it was. However, it was *a lot* and you can see the white tube with the 90 deg connector on it. That's the tube for the alk doser (and calc and RODI) which goes directly into the return pump.
The only things I can think of are:
-That tube has a whole mess of splitters, connectors, check valves on it. A few days ago there was a clog so I pulled it all out to clean it. I know I saw some alk coming out of it while I was messing around with it. But it appeared to be just the little bit left in the last few inches of that tubing.
-Earlier in the day, I had measured the alk at 7.8 and dosed more. I supposed it's possible the dosing pump went overboard, but the alk reservoir doesn't look all that much lower than it was the last time I looked at it. When I checked it, I was worried the entire thing was going to be empty. Also, I'd be surprised if (or maybe I am surprised that) I could have an alk of 7.8 with a giant pile of it sitting there. Surely a lot made it into the tank if that much settled out.

Also, I had, just a few hours earlier (just before I dosed it) pulled samples for an ICP test. I pulled them right from that section of the sump. I'm pretty confident I would have noticed if that was there when I was doing that.

Now, this all happened late last night. I removed just about all of it other than what got kicked up in the process. I wanted to let it settle and mix with the rest of the water before retesting alk, but I fell asleep and forgot about it until now. I'll test it later today when I'm home. It'll be interesting to see if it's still in the 8ish range or if it skyrocketed.

So is it alk? Is it something else? I have no idea.

.
.

One other thing I can think of. I hadn't been doing water changes for the past few days in either of my tanks. Last night I decided to do change a few gallons and the new water is pumped into that general idea. I suppose it could be from that, but I've never seen fresh salt water do anything like that.

I have never seen anything like that. It looks like a precipitate - in an area of low flow - and likely relates to your dosing. I would siphon it off - and re-measure your pH, Alkalinity Ca and Mg. If your Mg is low - it can sometimes cause precipitation like this. You c0uld also try merely 'stirring it up' - but that runs the risk (if it is partially 'dissolved' ca and bicarb (or whatever you're using) - of rapidly increasing the alkalinity. Thats why I suggest removing (carefully) that area, recheck your parameters, adjust Mg++ first - if needed - then adjust your Ca/Alkalinity.

Hope this helps.

 

[Cell]

Calcium carbonate? Have you measured pH?

 

[HBtank]

Yeah looks like calcium carbonate precipitate in a low flow area

 

[Joe31415]

I just checked a few of my parameters. pH is 8.2, Alkalinity is 8.2 and Calcium is 483. That's higher than usual for my calcium, which I normally try to keep around 440, but not so high that I feel like a dosing pump went rogue to the point of leaving all that behind.

 

[MnFish1]

I just checked a few of my parameters. pH is 8.2, Alkalinity is 8.2 and Calcium is 483. That's higher than usual for my calcium, which I normally try to keep around 440, but not so high that I feel like a dosing pump went rogue to the point of leaving all that behind.

THe key - is your Mg - If it's low - it will promote precipitation (PS - I agree that your dosing pump did 'something'. However - that is not like 'rock hard' precipitate - and may dissolve with flow - thus greatly increasing your parameter shift - Seriously - I would siphon it off - recheck your parameters including Mg - and dose appropriate to that.

 

[Joe31415]

Mag is 1480.

Seriously - I would siphon it off

That was the first thing I did.

 

[Joe31415]

I think I just figured it out. At the beginning I mentioned a whole big mess of splitters and check valves that I had taken apart and cleaned.
One of the tubes either didn't get reconnected or disconnected itself later. The end of the tube was resting on the rim of the sump, behind the pump. Each time it dosed it was just dropping everything right in that back corner. Since I haven't seen any more accumulate since I removed it, I'm guessing that was from when I did an extra dose to bump the alk back up. Regular doses that happen throughout the day are much smaller and probably made their way into the pump.