Reason for 24 hours settling of saltwater

[fijiwigi]

I haven't really understood why the saltwater has to sit for 24 hours with a powerhead before use so I researched. I have been told it needs to become aerated. I googled this article Making Saltwater from what I got from it is it needs to be mixed for 24 hours because freshly mixed saltwater is somewhat caustic (corrosive I think) Like getting salt burn?? once the salt dissolves in the water its not as caustic. From what I assume. the article didn't really state anything about a powerhead for aerating the water. I was thinking I could just keep a powerhead in my RO/DI so the water was already aerated and just let the salt settle for a few hours guess not. I assume the powerhead is really for just helping to mix the salt into the water faster so that it is less caustic. . Just thinking I could mix the saltwater in the AM and do the PWC in the PM but looks like thats out of the question. Just some general thoughts about mixing water. thought I would share.

[cmor1701d]

I too have been unable to find any science behind the mix/aerate for 24 hours before use. It may be due to salt mixes that do not dillute well, leaving unmixed traces behind. I don't know that anyone has proved that sw mixed for two hours is any more caustic than sw mixed for 24. The powerhead is more for mixing than for aerating the sw mix. You can do the same by putting anything in the container that would keep the water moving. A powerhead is just the easiest method of doing that.

I really don't see a reason that you can't do an am mix and pm change, but I'm also not going to take that risk on my tank

[Hara]

Mix two buckets of saltwater in an identical manner. Leave one sit. Put a powerhead in the other and make sure it is really well aerated (water movement at the top of the bucket). 24 hours later, test the ph in both.

[fijiwigi]

PH reasons make sense. My powerhead in my mixing tub is in the bottom of the tub do I need to point the power head toward the top to raise PH?? PH is it really like the oxygen level inside the water? What about freshwater tanks without powerheads is this why their PH requierment is less? would an airstone in a freshwater tank increase PH Just trying to understand things

[Innovator]

24hr mixing is called "aging" and allows your mix to fully dissolve and stabilize. Other than Ca, Alk, etc., pH can be a factor in relation to ambient CO2 in reaching a "normal" level (some salts are chemically made up to mix at a higher pH). If you are in a bind, many salts can be reasonably mixed within 2hr time frame.

[fijiwigi]

Originally Posted by Innovator

If you are in a bind, many salts can be reasonably mixed within 2hr time frame.

This is kinda what I was wondering. 2 days ago I added some Caribsea aragonite reef sand I rinsed it in a 5 gal bucket with RO/DI water then gently poured into my tank by lowering with a kool-aid type pitcher. My water turned so cloudy I couldn't see anything in my tank. Guess I didn't rinse well enough. it settled after half a day but everytime I move the sand even a little bit the entire tank turns cloudy again. I wanted to do a PWC but didn't mix my water until 8am this morning I work tommorrow and wanted to do the water change tonight.

The other question I have is say I mix my water to a SG of 1.025 but the water was cold after it warmed up I tested the SG and it was 1.020 so if I add 1 or 2 more scoops of salt to the water to reach the correct SG should I wait another 24 hours from that point or would 2 hours beyond that point be ok.

[Innovator]

I'm assuming this is for a new tank? When adding new sand, whether pre-rinsed or not, there is always some silt left over. I would gravel vacuum the substrate to remove the actual silt.

If the temperature matches that of the systems water I would add salt if needed.

[fijiwigi]

Originally Posted by Innovator

I'm assuming this is for a new tank? When adding new sand, whether pre-rinsed or not, there is always some silt left over. I would gravel vacuum the substrate to remove the actual silt.

Not that new of tank just wanted a nicer sand covering so my shrimp/goby pair would have a nice cozy home when they arrive this week. I think I will vacuum the silt and change about 15 gallons of the total 60gallons volume tonight 10hours after mixing the salt hopefully won't have any issues(PH is 8.2). In the future I need to do a better job of planning ahead.

[roka64]

Depending on if you are using a hydrometer or a refractometer, will depend on the readings of salinity. I mixed SW and was testing with a hydro (with cold water) and had hard times getting a good reading. My refracto is able to read at a larger range of temps.

[fijiwigi]

Using a refractometer I decided today that I am going to get a heater for the RO/DI container(32 gallon trash can) as well as my heater for the saltwater mixing tub. that way I always have the right temperature water on hand so that I can mix accurately I don't know the scale of SG to Water temp I know that temp affects it.