aggieMEDIC Posted October 8, 2012 Share Posted October 8, 2012 I understand that over time the water evaporates and the salt remains. My wife came home today and the tank was pretty bubbly which i know means it needs topped off. My tank is a stock JBJ NanoCube 24g. so here is my questions... why is my salinity right where it needs to be? i forget the number off hand and im currently at work, but i believe it was right at 1.022. I check it with a float guage. do I add NSW or RO??? if I add RO the salinity would suffer, but understanding my first sentence i know i shouldnt add NSW either. I do not have a refractometer. I thought had one but its been lost over the last few moves. Thanks in advance. Quote Link to comment Share on other sites More sharing options...
ClarkiiCircus Posted October 8, 2012 Share Posted October 8, 2012 Honestly, unless you have checked w/ a refractometer to ensure that your float gauge/hydrometer is accurate before, I wouldn't trust it. I have seen them be off by as much as .008. I would top off with RO. Most everything can handle salinity being lower than it should (mimics a heavy rain), but having salinity higher than it should be is a lot more stressful. Do you make your own saltwater? If you buy it at a store, it could be that they had just made it and it hadn't finished mixing when your purchased it, which would leave the water at a lower salinity than desired in the first place. (Ie, the water you originally put in your tank was low and the evaporation would increase it slightly). Take a sample of the water to be tested w/ a refractometer at any LFS or Petco if you want to be 100% sure, if you haven't already added. 2 Quote Link to comment Share on other sites More sharing options...
Bpb Posted October 8, 2012 Share Posted October 8, 2012 +1 on upgrading to a refractometer. I started my tank with a swing arm hydrometer, and for months couldn't figure out why my zoas wouldn't grow, and why my other corals were bleaching and lookin terrible. Half my cuc died too. Hydrometer was reading 1.025. I upgraded to a seawater refractometer (Veegee), and when I checked it I was shocked. What my hydrometer was reading as 1.025, was actually 1.032. I consider it a must to have a refractometer. Some may disagree. If I could go back, a refractometer and ROdi filter would have been the first two things I purchased before the tank itself even. Until you get one, you really have no idea what your salinity truly is. Quote Link to comment Share on other sites More sharing options...
jestep Posted October 8, 2012 Share Posted October 8, 2012 I had my first tank crash due to 2 faulty hydrometers. IMO, auto topoff and a refractometer are the first things I would get for a tank. Otherwise, I agree that you should topoff with RO and perform regular water changes. Quote Link to comment Share on other sites More sharing options...
Juiceman Posted October 8, 2012 Share Posted October 8, 2012 A nano won't differ much in salinity with that small of a water volume anyway. I only check salinity when I do a water change. Otherwise, I just top off with ro and call it a day. Also on the refractometer kick. My hydrometer is off by .001 ppm. Tested at my lfs against a refractometer. 1 Quote Link to comment Share on other sites More sharing options...
aggieMEDIC Posted October 8, 2012 Author Share Posted October 8, 2012 I agree I need the refractometer. Id like to find one local thats not an arm and a leg. Sent from my Galaxy S III using Tapatalk. Quote Link to comment Share on other sites More sharing options...
bige Posted October 8, 2012 Share Posted October 8, 2012 You top off with ro water. Once you know what your salinity is. You would only top off with sw if your salinity was low but a water change could fix that. Quote Link to comment Share on other sites More sharing options...
jestep Posted October 8, 2012 Share Posted October 8, 2012 (edited) If you don't have a refracto, just make sure you get your water from a good source and keep up with water changes using the exact same amount each time. This way the salinity should remain constant with the exception of salt being lost to salt creep or spillage. I wouldn't ever use this method if I were mixing my own water, but you should be more or less good indefinitely with strict volume control during a water change. Edited October 8, 2012 by jestep Quote Link to comment Share on other sites More sharing options...
DerrickH Posted October 9, 2012 Share Posted October 9, 2012 My old lever meter was off by .003ppm when I first got it so I marked it at 1.025(where I ran my SG). I dropped it a couple times getting in and out of the stand ect....next time I checked it, it was .006ppm off..... In short, get a refractometer, much more dependable. Also with a smaller volume of water, I would think that any change in the SG by adding RO water would be amplified DUE to the small amount of water in the DT compared to larger tanks. Like adding 10 gallons of fresh water to a 300g tank.....doesn't do squat but add 10g of fresh water to a 20g tank and see what happens..... Quote Link to comment Share on other sites More sharing options...
+etannert Posted October 10, 2012 Share Posted October 10, 2012 Also, you should really top off every day or two. Mark a "fill" line somewhere inconspicuous with a Sharpie, and refill to that line daily. Quote Link to comment Share on other sites More sharing options...
Bpb Posted October 10, 2012 Share Posted October 10, 2012 Auto top off is on my wish list as well. But I wanna research them more. Someone mentioned topping off everyday or two? I top off first thing in the morning, when home from work, after dinner, and before bed. I try to keep it as constant as possible. My in laws come by twice a day when I'm out of town to top off for me. I got my tank salinity to 1.024, and just mix my water for water changes to the same. I double check it each time with the refractometer. Top offs are always with RODI. Any salt lost due to skimming and salt creep is replenished with water changes so no need to salty up the top off water Quote Link to comment Share on other sites More sharing options...
Timfish Posted October 10, 2012 Share Posted October 10, 2012 If you want to top off every day or two that's fine. I have a top off on one of my systems but most just get topped off when I do a water change every week or two. I haven't had any problems with systems seing a 7% - 8% fluctuation and have moved corals back and forth without incident. One of the reasons I favor a big sump is it helps reduce the need to do frequent chores like topping off the tank. Quote Link to comment Share on other sites More sharing options...
Bpb Posted October 10, 2012 Share Posted October 10, 2012 Lol I am just a little compulsive. Quote Link to comment Share on other sites More sharing options...
victoly Posted October 10, 2012 Share Posted October 10, 2012 Lol I am just a little compulsive. you're in the right hobby Quote Link to comment Share on other sites More sharing options...
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