Reef nutrition

Another salt question

Srt4eric

Vice President
BOD
I'm currently using Fritz rpm salt. It comes is a 55lb box with 4 13.75lb bags in the box. The box states it makes 200 gallons. Is it safe to assume that I can just dump one of the bags into 50 gallons and that should be fine? Of course I'm going to test salinity after mixing. I've never had to make this much water at a time before.
 
Yes, seems safe to assume but at what salinity level. Does the box tell you what salinity it mixes 200 gallons at? It may make 200 gallons total at 1.024, but you may want to run at 1.026 or 1.025.
 
Yes, seems safe to assume but at what salinity level. Does the box tell you what salinity it mixes 200 gallons at? It may make 200 gallons total at 1.024, but you may want to run at 1.026 or 1.025.
The box states 200 gallons at 35ppt
 
If you want to run at 35ppt/1.026, then 1 bag per 50 gallons should be good. If you want lower ppt/sg you can just add a little more water.
 
When I’m using salt I’m not as familiar with I first add about 80-90% of what I think I’ll need, fully mix it, then test salinity. Then add more as needed to get to target salinity. Keep track so next time you can just add the right amount.

Also when you say just dump the salt in, just wanted to point out that you shouldn’t just dump a whole bag of salt in. You need to add it in smaller amounts while mixing, letting each addition mostly dissolve before the next. If you just dump it all in you are more likely to have problems with incomplete dissolution and precipitation, that you won’t be able to fix with just more mixing. I made this mistake routinely during my early years of reefing.
 
When I’m using salt I’m not as familiar with I first add about 80-90% of what I think I’ll need, fully mix it, then test salinity. Then add more as needed to get to target salinity. Keep track so next time you can just add the right amount.

Also when you say just dump the salt in, just wanted to point out that you shouldn’t just dump a whole bag of salt in. You need to add it in smaller amounts while mixing, letting each addition mostly dissolve before the next. If you just dump it all in you are more likely to have problems with incomplete dissolution and precipitation, that you won’t be able to fix with just more mixing. I made this mistake routinely during my early years of reefing.
I have a powerhead running in my saltwater barrel, just slowly pour it in. Fritz dissolves pretty quickly even in cold water.
 
Same.
In addition to problems with incomplete dissolution and precipitation, I imagine the slow pour is easier on my recirculating pump doing the mixing.
 
What you want is a line on your mixing barrel that shows exactly how much water is needed
before you add the salt, such that a full bag ends up just right.

That is not so easy.

Step 1:
Fill barrel with about 45G of water. Less than will be needed by a bit.
Mark that line temporarily.

Step 2:
Add ALL the salt. Yes, salinity will be a bit high. That is ok unless way high.
(Slowly of course)

Step 3:
Measure the distance between that temporary line in step 2 and where it is now.
That is the extra volume due to salt.

Step 4:
Slowly add water, measuring salinity, until it is exactly what you want.
Usable now.

Step 5:
Subtract the distance in step 3 from the current water level, and mark that line permanently.
That is the key line for next time.
Just fill to that line with RO. (or have float valve stop there)
Then you can simply dump in a new bag, no measuring needed other than a quick double-check at the end.
 
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