my SG never drops, no matter what?

TomCs · 09/18/2008, 07:53 PM

i posted about this a couple weeks ago and still cant find any answers. i do use natural sea water with SG 1.024. i have an open hood tank that gets a good 3cm (1.2inch) of evaporation every day or so and i test several times a day and get no change in my readings. its been four weeks now since ive had the tank up and running and i havent needed to add RO once??? believe me i want to but every time i test when the water level drops its still at 1.024 so i make myself top up with more salt water. i test again an hour or so later and i still get 1.024. i think the answer lies with me using a swing arm hydrometer (i no i need a refractometer), i test multiple times, i rinse between uses and make sure no tiny bubbles sit on the arm so even though it may not quite be 1.024 its definitely not changing....any help? im adding peppermint shrimp soon so id like the SG to be spot on or at least stable.

microbubbles · 09/18/2008, 07:56 PM

it's broken... it defies all logic and reason that you have to make up water, yet there's no change in specific gravity. get a new hydrometer, or a good quality refractometer (even these will give incorrect readings if you go cheap). good luck

killagoby · 09/18/2008, 07:57 PM

Your SG should not be dropping with evaporation. It would increase. As the water evaporates, the salt remains, thus increasing the SG.

Kdocimo90 · 09/18/2008, 07:59 PM

Quote:

Originally posted by killagoby
Your SG should not be dropping with evaporation. It would increase. As the water evaporates, the salt remains, thus increasing the SG.

+1

AquaReeferMan · 09/18/2008, 08:46 PM

Get a refractometer. Believe me, your SG is fluctuating. The swing arm is just not picking it up, simple as that.

sps1-2-b · 09/18/2008, 08:59 PM

+1 on refractometer. It's a practical purchase compared to our investment in our livestock.

woogy · 09/18/2008, 09:01 PM

are you planning to do a water change? If so check the SG of the new water and see what it comes out to. If it reads 1.024 like your tank well u know

BTW...get a refractometer

tmz · 09/18/2008, 09:34 PM

I agree your measurement is off, A refractometer or salinity meter is much better than a sing arm. They are very inaccurate and prone to dificulty.

09/18/2008, 07:53 PM	#1
TomCs Registered Member Join Date: Jan 2008 Location: Australia Posts: 152	my SG never drops, no matter what? i posted about this a couple weeks ago and still cant find any answers. i do use natural sea water with SG 1.024. i have an open hood tank that gets a good 3cm (1.2inch) of evaporation every day or so and i test several times a day and get no change in my readings. its been four weeks now since ive had the tank up and running and i havent needed to add RO once??? believe me i want to but every time i test when the water level drops its still at 1.024 so i make myself top up with more salt water. i test again an hour or so later and i still get 1.024. i think the answer lies with me using a swing arm hydrometer (i no i need a refractometer), i test multiple times, i rinse between uses and make sure no tiny bubbles sit on the arm so even though it may not quite be 1.024 its definitely not changing....any help? im adding peppermint shrimp soon so id like the SG to be spot on or at least stable. __________________ "A thing is right when it tends to preserve the integrity, stability and beauty of the biotic community. It is wrong when it tends otherwise."(Aldo Leopold 1949). Current Tank Info: 50gal reef since Aug 08.

09/18/2008, 07:56 PM	#2
microbubbles Registered Member Join Date: Dec 2005 Location: Hacienda Heights, CA Posts: 1,010	it's broken... it defies all logic and reason that you have to make up water, yet there's no change in specific gravity. get a new hydrometer, or a good quality refractometer (even these will give incorrect readings if you go cheap). good luck __________________ flush out your headgear new guy. Current Tank Info: 90g: atb medium cone w/ airstar, schuran jetstream 1, aqualogic 1/3hp trimline, 2x250w de lumenbrights on a bluewave vii, tunze 6200, 6000, osmolator, panworld return + c/l

09/18/2008, 07:57 PM	#3
killagoby Registered Member Join Date: Jun 2005 Location: Monroe, NJ Posts: 2,150	Your SG should not be dropping with evaporation. It would increase. As the water evaporates, the salt remains, thus increasing the SG. __________________ How much money did you spend on that rock again?

09/18/2008, 08:46 PM	#5
AquaReeferMan Got Reef? Join Date: Aug 2005 Location: Under the Sea, Pa Posts: 4,593	Get a refractometer. Believe me, your SG is fluctuating. The swing arm is just not picking it up, simple as that. __________________ Couple SPS/Zoanthid tanks and a couple of FW planted tanks. Current Tank Info: 5 pieces of glass with some silicone and plastic frames holding them together

09/18/2008, 09:34 PM	#8
tmz ReefKeeping Mag staff Join Date: Apr 2006 Location: West Seneca NY Posts: 27,691	I agree your measurement is off, A refractometer or salinity meter is much better than a sing arm. They are very inaccurate and prone to dificulty. __________________ Tom Current Tank Info: Tank of the Month , November 2011 : 600gal integrated system: 3 display tanks (120 g, 90g, 89g),several frag/grow out tanks, macroalgae refugia, cryptic zones. 40+ fish, seahorses, sps,lps,leathers, zoanthidae and non photosynthetic corals.

09/18/2008, 08:59 PM	#6
sps1-2-b Registered Member Join Date: Nov 2007 Location: Anaheim, CA Posts: 1,248	+1 on refractometer. It's a practical purchase compared to our investment in our livestock.

09/18/2008, 09:01 PM	#7
woogy Registered Member Join Date: Mar 2007 Location: Western PA Posts: 986	are you planning to do a water change? If so check the SG of the new water and see what it comes out to. If it reads 1.024 like your tank well u know BTW...get a refractometer