Alkalinity dosing turning to “snow”

[cshouston]

I tested my tank today and the results were:
pH 8.3
Alkalinity 8.1
Calcium 440
Magnesium 1320

I dosed 10ml of Red Sea Reef Foundation B as I’m trying to slowly raise my Alk to 9. I dose above my MP40 and noted that it was starting to precipitate before it even hit the flow. Once it hit the flow, it basically blew across the tank as particles that didn’t seem to fully dissolve. Some of the fish were even trying to eat it! I added another 5ml to my sump over the return pump, but most of it settled out around the pump as precipitate. Am I missing something? Is there some imbalance causing this or am I overthinking it? Thanks in advance.

 

[725196]

I don’t use that anymore but when I did I would pour it in the overflow so it would not precipitate out like that. And if it did it was in the sump.

 

[Homebrewer]

Dilute it further. Add the 10mL to maybe another 100mL of RO/DI. The lower concentration should prevent precipitation when the larger volume hits the saltwater.

I don’t have an ATO. I use two part. I add the Ca directly to the tank, but I add the Alk to the daily top-off water then add the whole thing to the tank. No cloudiness or precipitation.

 

[cshouston]

Dilute it further. Add the 10mL to maybe another 100mL of RO/DI. The lower concentration should prevent precipitation when the larger volume hits the saltwater.

I don’t have an ATO. I use two part. I add the Ca directly to the tank, but I add the Alk to the daily top-off water then add the whole thing to the tank. No cloudiness or precipitation.

Thanks. I’ll give that a shot. I do have an ATO, but I’ll just try diluting 10ml in 100ml of RO like you suggested.

 

[Homebrewer]

Thanks. I’ll give that a shot. I do have an ATO, but I’ll just try diluting 10ml in 100ml of RO like you suggested.

Yeah I mean I had the same problem you did. No amount of flow was preventing precipitation. Because I do the manual top-off, I just made it part of my nightly habit.

 

[Randy Holmes-Farley]

Some cloudiness is normal. It is magnesium hydroxide that will temporarily form with any high pH additive. It will redissolve on mixing in.

Adding it more diluted, more slowly, and to a higher flow area will disperse it faster, before there is a chance to form the more problematic precipitate of calcium carbonate, which will not redissolve.