Why is my SG so high?

[chickenofthesea]

Ok, so I purchase saltwater from my local fish store. I tested it when I first started buying it and the SG is always 1.023. I noticed recently that my mushroom spend a lot of time closed up when ussually they are spread wide open and taking in the light.

I tested my parameters and the only thing off was my SG. It was at 1.028 and though my fish seem to be fine, this seems really high. All my corals look great and my coralline has started blooming all over the place.

What I can't figure out is why my SG is getting so high. I don't add salt and I do a 10g water change every other week (my system is 44g). Why is my SG climbing?

 

[Boomer]

First what are you testing it with exactly ? And what is the salinity of the salt you are adding to it ?

 

[MGDMIRAGE]

And are you always replacing evaporation with fresh water?

 

[Frankie]

Both posts pretty much sum up the problem here.

How are you testing your salinity and what are you doing to top off evaporated water with?

You need to add freshwater as it evaporates from the system. Salt will not evaporate, so as the freshwater evaporates from the system the salinity go's up. If you add back saltwater then it go's up even more. To maintain a specific gravity you would need to top off with freshwater.

Be sure to top off with RO or better quality freshwater to avoid potential contaminates. No tap water.


Next we should talk about what the saltwater salinity level should be.

Frank

 

[chickenofthesea]

I use a Coralife Deep Six Hydrometer. I know these aren't the most prefered but I have had my water tested by my LFS in the past and our readings were the same. I do not top off with freshwater. I didn't think about the evaporation being a problem because of salt creep. When I go get the water for my next change, I will be sure to pick up a 5 gallon of RO as well. Should I use any of the RO water for this change to bring the SG down or should I do my normal change and then just start topping of with the RO?

So now that we have that out of the way, school me Frank!

 

[Boomer]

The Deep Six is the worst thing to measure seawater with. And the LFS tested your water with what ? If there is a realness to your readings and the LFS then it was due to doing WC and not taking in Evap.

 

[CoralPropsMichael]

As has been mentioned, evaporation needs to be replaced with fresh water, not salt water. I'd suggest investing in a refractometer. These can be calibrated and tested, against a reference sample, to improve accuracy.

 

[chickenofthesea]

The LFS used a refractometer and because I purchase the water from them and it reads 1.023 with their refractometer I have no reason to believe the problem is any thing more than what you have all said, not topping off with fresh water.

Hey boomer, what do you mean by "Doing WC"? I don't know what the wc stands for.

I am totally on board with purchasing a refractometer but I am a reefer who is in the military and on a very tight budget so it has been low on the list of things to get since I do have a way to measure the SG.

 

[MGDMIRAGE]

Yeah what it sounds like is you are getting a bit of evaporation and not replacing it but doing water changes each week and probably filling tank up to normal level. All the while you are slowly increasing your salinity, keep the tank topped off with fresh RO water, a tank your size should lose around a gallon a day unless its fully covered.

WC = Water Change

You could start lowering the salinity now by tanking out a gallon of saltwater and replace it with fresh, do that each day until the salinity is where it is supposed to be.

And yes while hydrometers are considered not very accurate, i too have a couple and one is a deep six and its dead on with my refractometer but not all of them are.

 

[Frankie]

WC = Water Changes

I agree that the deep six is good for a land fill or something. Invest into a refractometer as Michael suggested.

Your going to raise your salinity to 1.026 SG at a temperature between 76-80f. I shoot for 76-78f.

Basically were riding you to consider making your own saltwater and investing into an RO/DI filter unit to filter your tap water. Buy your own salt and learn the chemistry of your aquarium water.

Frank

 

[Guerry]

+1 Frankie, most LFS use the cheapest salts they can buy and while 1.23 may be fine for a fish only system corals perfer 1.26 JIMO

 

[chickenofthesea]

I am looking into making my own saltwater. I have a few really nice frags I am waiting to sell and as soon as they are gone I will be investing in my own RO/DI system. So much easier and not so hard on the gas tank as driving 20 min to the LFS every week. I promise I will work on the refractometer, lol. As for now, the Deep Six is all I have so I will make the best of it.

I purchased some RO/DI along with some saltwater this morning so I will do my normal WC minus one gallon and add the RO/DI to top it off. I will update this post this afternoon as soon as I do the change and test the water.

 

[IPisces]

+1 Frankie, most LFS use the cheapest salts they can buy and while 1.23 may be fine for a fish only system corals perfer 1.26 JIMO

You do mean 1.026 I'm sure.

 

[Boomer]

I hope so Pis

 

[chickenofthesea]

I did my water change on Sunday and replaced a gallon of saltwater with a gallon of fresh and brought my SG down to 1.025~. I will continue to replace evaporated water with fresh between water changes and try and keep the SG as close to 1.026 as possible. I am still having issues with the one red mushroom staying balled up but its not dead so I'll continue to keep a close eye on it. Hopefully it recovers.