Specific gravity too low

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leafyseadragon

Aquarium Advice Freak
Joined
May 29, 2003
Messages
205
Location
California
I just started setting up my first SW tank. :D

I first put the washed aragonite sand in. Then I added water, 3 gallons at a time, using a jug. I added a 1/2 cup of IO per gallon like the bag said. I didn't add the salt to the jug, I dumped it into the tank after each jug of water.

I attached the heater to the tank and plugged it in. I also put in an airstone to circulate the water. When I left the tank, it was really cloudy.

This morning the tank is still cloudy, but I can see the outline of the heater in the back. I checked the specific gravity with a floating glass hygrometer, and it's only 1.018 or so. Is this because:

1. I need to wait longer for the salt to dissolve because I just dumped it into the tank.
2. I have to add more salt.

I was hoping to add the LR today, but I better have the SG worked out first.
 
IMO I would say ditch the floating Hydrometer and get yourself a deepsix or a seatest. From My experience the floating ones are not that acurate.. Depending on the size of the tank and the filter system it could take a few days for the water to begin to get clear.. IMO if its a 55gal or above i would wait approx 48hrs before adjusting the salinity. You might try mixing up the Lower Portion of the tank as well.. It will add to the cloudiness but should help in adding the salt it get properly mixed into the water.. From my experience with larger tanks it seems if you mix the salt in the tank it takes a little bit of time for it all to dissolve.. But thats just MHO.. If I am incorrect someone please correct me.


Just my 2 cents worth,
James
 
The deep six and the seatest's are not even very accurate...the only way to get a good accurate measurement os to by a refractometer....They can be a little pricey but if you want close to exact...thats what you have to get....now, I use a seatest, but only untill I can get a refractometer.....Drop a Powerhead or two into your tank .....they will help the water circulate and mix the salt so you don't have to get in there and do it by hand. Test the salinity after the water is up to temp and it has cleared. If it is still low....just add more salt and let it mix untill you get the right numbers :wink:
 
Large floating hyrometers (as those used in brewing) are very accurate, much more so than a swing arm hydrometer.
 
I just tested the water with an Aquarium Systems SeaTest Hygrometer. It read 1.0215 (I carefully tapped out the air bubbles), but the floating glass hygrometer still reads 1.018. I am inclined to believe the SeaTest, but should the two readings be this far off?

BTW, it's been 48 hours and the tank is still a little cloudy. Is this normal? I have yet to get a powerhead. Probably tomorrow.
 
IMO my tank has been running for about a week now its a 55gal.. I have a Magnum 350 on it using a paper filter for now.. It just got cleared up just the other day.. I think it took about 3 or 4 days for the water to be crystal clear.. My Salinity is 1.023 @ 80F The floating Hydrometer is that the one with the thermometer on it? I would tend to believe the Seatest one... I believe my floating hydro reads about that much off as well. When i first set up my 29gal I bought the floating one and adjusted it to where it read 1.023 and then decided to buy the Deep Six. That one stated that my SG was 1.027.. What filter are you using.. and with what media is in it?

James
 
My tank is a 37 tall. There is nothing in it except sand, salt, water, and a small airstone. Yup, the floating hygrometer also doubles as a thermometer. I thought it was giving accurate readings because it recorded tap water at 1.000.

There is no filter for the tank, I was planning on adding LR once the tank clears.
 
ok

reefrunner69 said:
Large floating hyrometers (as those used in brewing) are very accurate, much more so than a swing arm hydrometer.
where do you get one of these?
 
I would trust the floating hydrometer over the seatest hydrometer. They are more accurate, as Kevin stated.

They can be purchased a few places. Any homebrewing/wine making store will have them. I actualy saw some on the shelf of a new LFS I found (color me impressed) They can also be found in ceramic supply stores some craft stores may even carry them. (the hunt is on!)

I just ordered a refractometer cause I can't stand the seatest POC and my brother keeps hogging my floating hydrometer after we brew...

Leafy, I get the impression that part of your cloudiness issue is partly due to the lack of water movement, your salt isn't completely disolving in the tank. By now it probably is all disolved but i think the cloudiness are other particles that need to be completely absorbed.. The airstone is certainly moving some water, but very little, and especialy in terms of a SW tank. Run out at pick up a few PHs. You're going to want about a total of 400GPH when your tank is set up anyway, so I would start now :D
 
My deep six is spot on to my new refractometer. :|

I use instant ocean salt which is supposed to be a rapid desolving but it still took about 24hrs for the salanity to quit rising. I guess it needs to completely dissolve.

a piece of advice, take a min of 3 measurements for I've gotten some way out of whack readings before. You get 2 or 3 the same and call it good. Also be sure to wash it completely with freshwater after each use. The moisture left inside will evaporate leaving the salt which will drastically obscure the next readings.

I would also assume that alot of your salt fell to the sand before it was disolved. I premixed mine, poured it in an empty tank and still ended up with salt laying on the bottom.

I also find that circulating the water w/o a canister or HOB type of filter, only prolongs the cloudiness. You're not allowing the particals to settle with the circulation.
 
Also be sure to wash it completely with saltwater after each use
I'm pretty sure dogofwar meant rinse with FRESH water, which is what you want to do.

in terms of cloudiness from salt.. you don't want it to settle, you want it to disolve into the water. if the salt settles and doesn't get disolved i'd be worried about a sudden spike in salinity if something stirs up the settled salt in the future.
 
I think the best way to mix your salt whether it be in the tank for a new set up or in a bucket for water changes is to use PH to mix it up. Let it run for a few hrs or even a day or so, the water will constantly be moving and the salt will mix better. You won't have to worry about settling salt and lots of fluctuations in readings when testing it. Also, make sure it is at the temperature of your tank when tanking the readings as well.
 
BillyZ said:
Also be sure to wash it completely with saltwater after each use
I'm pretty sure dogofwar meant rinse with FRESH water, which is what you want to do.

in terms of cloudiness from salt.. you don't want it to settle, you want it to disolve into the water. if the salt settles and doesn't get disolved i'd be worried about a sudden spike in salinity if something stirs up the settled salt in the future.

:oops: YEP, my bad, SW would defeat the whole purpose.
 
IMO, this is probably from two reasons, some salt that had settled originaly, and perhaps some sand/silt is beign kicked up from the new PH. it will certianly clear up.. you should be well on your way.
 
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