When to use salt for top off?

[Reefahholic]

I've always heard from the beginning that the salt stays in the tank and to top off with fresh RO/DI water.

Seems like this holds pretty true with my DT with all the sand and rock. I've been topping off about 1 gallon a day and not much change in salinity. Apparently it gets caught up in the sand and rock, which makes the salinity hold more constant.

However, My QT is a little different (bare bottom of course). I did a 40% WC today and topped off with complete saltwater with SG of 1.025 Cause my salinity was a little low and it brought it back to 1.025. Probably just luck, but it was spot on.

Just wondering what you guys have experienced over the years and how and when you add saltwater vs fresh.

My concerns with a tank full of corals and fish are possibly shocking the system. Now I see the need for small WC's at a slow rate. Maybe like weekly or biweekly instead of monthly. Especially if you have a tank full of SPS.

I noticed watching a Live Aquaria video, that they have both salt and fresh water stock tanks ready to use either/or for top off. Do any of you guys have two top off containers?

 

[mike_cmu04]

No I only top off with fresh water if my salinity drifts I will do a water change with a slightly higher salinity but it mostly stays right on

 

[Reefahholic]

Do you pump it in slow or just dump it in fast.

If you have a sump less QT (like most do), what's the best way.

 

[Jneighbors]

It's best if you just pump it in, pour it in really slow or use a cup.

 

[Chronicj7]

Your ATO is the best way to add the salt if it is low.

 

[Reefahholic]

Wouldn't that leave a lot of precip over time.

I wouldn't want to use salt and fresh in the same reservoir, or is that what most people do?

 

[dwd5813]

Shifts in salinity would typically only happen as water evaporates from the system. Salt does not evaporate so when the water does, the overall salinity increases and as fresh water is added during top off the salinity returns to normal. If too much fresh water is added the salinity will decrease and salt water will have to be added to bring it back. I would do this the way mikecmu04 describes, during a water change. Alternatively, or in the case of a sumpless tank like the QT you describe, I would simply remove a few cups of water from the system that is running a low salinity and replace with water of a normal salinity. Check the salinity often, allowing time for adjustment, and repeat until salinity has normalized. I would not add saltwater to my ATO personally, for the reason you describe.

 

[MXracer52]

i top off with fresh and if the salinity get’s low I adjust accordingly on the water change

 

[Reefahholic]

So it's really a guessing game after you know it's low. I was hoping there was a prescription as to if the salinity was this- you add that.

So just add slowly until you get it back up. That's it...got it.

 

[Reefahholic]

So it's really a guessing game after you know it's low. I was hoping there was a prescription as to if the salinity was this- you add that.

So just add slowly until you get it back up. That's it...got it.