Question about salinity/SG

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limitup

Aquarium Advice Regular
Joined
Jun 30, 2004
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57
Location
Dallas TX
I'm new to the hobby so please bear with me if this is a dumb question ...

I have a 150g tank that is set in the wall in my living room. The space it is in is basically the area under the stairs that go upstairs, and there is a door to gain access to everything. So basically it's a tiny enclosed room. This required the use of a chiller, which generates even more heat.

Because it's a small enclosed room and it gets hot, we get quite a bit of evaporation. This is replenished automatically with clean fresh water that also has some calcium in it.

So generally speaking, if you replenish what evaporates with fresh water, overall your salinity/SG should stay about the same right? However, I do notice quite a bit of salt residue on just about everything in the room so obviously some of the salt is also leaving the tank via evaporation.

I don't know if this is the reason, or if my salinity has always been this low and I didn't realize it because I was using a crappy hydrometer, but I just bought a high-end refractometer and my water is about 1.022 which is too low according to the "expert" who helped set everything up. He says I want to be right around 1.025.

He is out of town for a few weeks and I am just curious how to go about raising it from 1.022 to 1.025. I assume there is some type of salt mix or other solution I can buy and slowly add to the tank to bring it up?
 
I would say the "easiest" way to raise your SG back up to 1.025 would be to mix your top off water to a salinity of 1.025 each night. Keep doing so until your main take comes back up to 1.025. Any salt water mix will do, but people say its best to stay consitent, do you know what type was used in making up the salt water for the tank and for water changes?
 
Do it slow, jerking it up all the way in one shot will stress the fish and other life inside.


also, the salt is all over the room? its probably from splashes and not evaporation, salt can't evaporate. It gets left behind when water evaporates.
 
That's pretty strange ... all I know is that everything in the room is covered with a thin layer of salt and it's not from splashes. If you lick the wall it even tastes a little salty. I think a little bit of salt does evaporate, that's the only thing that would explain it. I actually grew up in Hawaii and one of the things that happens in Hawaii is that anything metal rusts pretty fast. It's not unusual to have a 5-10 year old car that is covered with rust. Everyone says it's because of the salt in the air ...
 
It sounds like you could use some ventilation in the small space. You should think of some way of installing fans to bring in cool air. Maybe a bathroom vent fan?
 
Yeah we have been thinking about that. However, the noise level is a factor. The system is already pretty loud with all the pumbs, the chiller, etc. Cutting a hole in one of the surrounding walls to make a vent will just allow that much more noise to escape into the surrounding areas of the house. Not sure we want that.

The evaporation is not really a problem. I have a big tank that I just pour 5 gallons of clean fresh water into it at a time as needed. It refills the tank automatically, so it's no big deal aside from the apparent salinity change over time.
 
Its not evaporation, it's humidity...the air is damp with saltwater (so it's not technically evaporating)...that coats the walls, and then the water evaporates.

So you're both right, just using inaccurate terms :)
 
Cool, that makes sense. Is there some way to combat this "problem" automatically? I guess I could set-up some kind of drip system that drips really salty water into my refill tank, which would increase the salinity of that water a little, which would then slowly increase the salinity in my tank as it refills the tank? Or is this something I need to do manually all the time?
 
Also, one other question. If I just want to raise the salinity a tiny bit at a time, is it OK to just pour a tiny bit of salt mix into the sump every now and then. I mean a really small amount - like a quarter cup here and there. Then check the SG a day or two later, etc. Or do I have to go through the whole process of actually mixing up separate salt water, aerating it for a day, etc. etc. before pouring it in??
 
Or do I have to go through the whole process of actually mixing up separate salt water, aerating it for a day, etc. etc. before pouring it in??

I would say yes....leaving it for a day makes sure everything is fully dissolved, even the stuff you can't see. If the salt were to get on a fish or a coral it could pretty much burn it for a lack of a better word and kill it
 
if you have a fish only tank. i would just recommand to keep the salt level about 1.017 - 1.019, that way it could help reduce the risk for parasites infection ike infection on the fish, i keep my about 1.017 for my 60 gals and 1.018 on my 10 gals. and all my fish and live rocks are doing fine :mrgreen:
 
That's not healthy... you shouldn't keep fish at anything that far below NSW levels.
 
i went to all my lfs, and they suggested me to keep it at that level and i see my fish really healthy and my lfs fish is really healthy too.
 
It's detrimental to the normal physiology. Other than that, it's your call.
 
Atari said:
It's detrimental to the normal physiology. Other than that, it's your call.
Agreed, it also does absolutely nothing for parasite control. :wink:

Cheers
Steve
 
I've heard that it does help with parasite control, that's why all the LFSs do it - they have less chance of selling you a fish that will die and they will have to replace out of their pocket. More importantly however, once fish are in your established tank, a higher number like 1.025+ will really help to draw the ammonia out of your fish which will keep them super healthy. Fish rely on the salt in the water to draw the ammonia out of their bodies.
 
Call me cynical but I suspect the LFS does it to save on salt more than anything. In any case, a few weeks of hypo in an LFS isn't so bad, but permanent housing in low salinity is very bad. I think that was the point trying to be made.
 
OK Atari, you're cynical - lol. That may be true in some cases, but my lfs, which I don't think would do it to save money, keeps theirs at 1.018. I think it MAY help with parasite control but is not good for the long term health of the fish. Per steve-s's advice, I keep mine at 1.024-1.025.
 
I don't think Atari is cynical at all. I think there are many LFS that do this to save money. There are even more that are completely miguided by this belief. I can assure you, there is no way a SG that high will affect a parasite with any benefit.

Cheers
Steve
 
Dunno if this would work, but could limitup use a small dehumidifier to combat the problem of the salt depositions? - might be a lot quieter as the unit would be in the fishtank room (as the extractor idea was nixed!) just a thought!
 
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