Alk dropping in storage

authentic · May 9, 2016

I keep 50 gal of SW in storage for my automatic water change (stenner)I'm down to about 20 gal,the storage lasts me about 6 weeks.just checked my alk and it tests at 4.7,checked with Hannah and salifert.magistrate at 1300.it was 8.5 when I filled it.could alk drop like this over time?..also checked salinity..still on point at .25

joshkirkland83 · May 9, 2016

Yes, thats why most salt manufacturers recommend using their salt in a few hours after mixing.

Downbeach · May 9, 2016

Do you have any pumps or heaters in the containers?

Randy Holmes-Farley · May 9, 2016

I'm a bit surprised it got that low. Did you measure it earlier in this same batch?

authentic · May 9, 2016

Yes I did measure when first mixed ,, it has a heater and a pump that mixes it occasionally during the week,,, any ideas why it would get that low??

JOKER · May 9, 2016

After mixing it once I wouldn't heat or run a pump. Will cause precipitation. I have some I mixed a month ago in mine. Got me curious so im going to check mine.

twilliard · May 9, 2016

Same here also. My alkalinity will drop if not used within 24 hours

Randy Holmes-Farley · May 9, 2016

authentic said:
Yes I did measure when first mixed ,, it has a heater and a pump that mixes it occasionally during the week,,, any ideas why it would get that low??

No, but there's no need to stir it after initial mixing. I leave mine for more than a month. Yes, there will slowly be some calcium carbonate precipitation, but generally it is not that important, and unless you are doing big water changes, it likely doesn't matter much.