Help with stability

[Whiterabbitrage]

How do people keep their salinity stable? I thought bigger tanks were supposed to be more stable but this tank has been nothing but problems since day one. One of the recurring problems is holding a stable salinity. I had rigged up an ATO to drip R/O water into the sump at a drop every five seconds but that ended up being a disaster. Also the tank seems to evaporate at different rates on different days. How do other people cope? Is an osmolater the only solid choice?

 

[kmbyrnes]

Define stable. My salinity has been 1.025 or 1.026 for almost 2 years during my weekly tests. There has been one 1.024 and one 1.027. That seems pretty stable to me.
I have an ATO system and a float valve in the sump. If my water level drops enough to trip the float switch, the ATO will refill it. Usually happens about twice a day.

 

[C.Eymann]

How do people keep their salinity stable? I thought bigger tanks were supposed to be more stable but this tank has been nothing but problems since day one. One of the recurring problems is holding a stable salinity. I had rigged up an ATO to drip R/O water into the sump at a drop every five seconds but that ended up being a disaster. Also the tank seems to evaporate at different rates on different days. How do other people cope? Is an osmolater the only solid choice?

there are many good ATOs on the market, but the osmolator is by far the most redundant, fool proof option.

 

[Ron Reefman]

You have almost 1300 posts here at RC and you are having trouble keeping your salinity stable? How is that even possible? I have 4 tanks with fairly heavy evaporation and my salinity hardly moves at all.

What is the range of your salinity swings and over what period of time? Are you doing water changes? Is that possibly a source of salinity being 'unstable'?

 

[gone fishin]

My salinity does not really move unless I make it move. I have had an osmolator for quite awhile now and no issues with the unit or salinity.

 

[Marchillo]

The reason why you are having trouble is bc you are dripping water in that doesn't correlate with the evaporation.

I have two tanks one with a JBJ and one with a hydor ato. They are ok. I've never used a tunze but they are supposed to be best. I've also heard good things about smart ato.

Just get an ato. Even with the cheaper ones my salinity is stable. I have the JBJ rigged so if the first float valve fails the second float valve will shut off the unit. Neither one of my Atos have failed.

 

[Marchillo]

One other thing. When doing your water changes make sure you match the tank. I use a digital refractometer that I calibrate but no matter what I test the display water and the water going in. That way even if the meter is off .01 etc I am keeping things stable. Also make sure the volume going in matches the volume coming out.

 

[lmforbis]

I use a gravity ATO. I is just a float valve similar to the one in a toilet. It is made by eshopp and cost around $20. It works well. Keeps everything very stable.

 

[jayball]

Yeah, just get an ato. A stand alone or some float switches on a controller.

 

[Coelli]

If you have a 150g tank and salinity is fluctuating that much... what are you measuring it with?

 

[Sk8r]

FLoat switch or pressure tube. I use one from Avast, a little less sensitive than a pressure switch, but my salinity in a 105 is rock steady for weeks. It's fairly inexpensive.

 

[Fish Keeper82]

Wet skimming can affect it aswell if you are getting alot of wet skimmate and adding fresh water to top the balance will be a salinity rate that will constantly decine untill you make up for it in a WC. Something to consider if your salinity is dropping. Thats why i tend to dry skimm.

 

[CStrickland]

I made this one and added a relay and a snail guard. Was cheap.
http://www.melevsreef.com/node/684
It's probably no more difficult than setting up the steady one you have now. Anything that is adding water according to how much evaporates is going to be more stable than a constant drip.

 

[Whiterabbitrage]

Thank you guys. Seriously. I have become so frustrated over this that last night I was considering giving up the hobby. My last tank was so successful. Now to have problems with something so basic, it's embarrasing, humiliating, and so aggrivating. The specific gravity has bounced from 1.021 to 1.027! It's ridiculous and I can't figure out how it's even happening which is even more frustrating. I measure with a salinity check probe and double check with a refractometer. Yes, they are both calibrated. Yes, I have a fresh battery in the digital probe. Yes, I match parameters when I do a water change. I don't know what's causing this. It's been happening since summer. Pretty much all my corals are toast now. I've watched them die one by one. We are down to a few Zoas and a toadstool leather that has had no PE for weeks. It's pathetic. I'm so frustrated. Your kind words and ideas really help. I've ordered a lab grade salinity probe, osmolater and salinity alarm. My last tank never needed all this. I think this new tank is cursed. Sigh.

 

[droog]

An ATO that replenishes the evaporated water with RODI should keep your salinity rock steady.

I bought this digital refractometer for testing water and found it was the best piece of equipment I ever bought. I keep 35ppt and salinity never varies by more than 1ppt.

A few caveats

1] Your float switch needs to be installed in the section of the sump that changes water level as evaporation happens. Usually thats the return section. You may need to create this section in the sump if its doesn't already happen

2] Set the ATO to drop 2 drops/sec or so when the float switch is "open"

3] Don't mess with the ATO once its setup

I used a tank maintenance service last year and discovered that the maintenance guy would mess with the float valve every week! My salinity would bounce up and down as the ATO reservoir dumped water into the tank. Fired the guy - rock steady salinity ever since...

-droog

 

[Ron Reefman]

A swing in salinity from 1.021 to 1.027 is a huge swing, but unless it happens very quickly, it really shouldn't be killing your corals. How fast does that kind of a swing happen?

You would have to do 5 water changes of 30 gallons each with new water that was 1.030 in order to raise your salinity from 1.021 to 1.027.

Or the other way, to get from 1.027 down to 1.021 you would have to remove 35 gallons of tank water and add in 35 gallons of fresh water!

That's crazy man. I'd be looking very seriously at your tools.

 

[Sapelo]

For what it's worth, we upgraded from a 90 to a 300 this summer. I don't think I ever gave salinity more than a passing thought in the 90 but with the 300 it's been much more of a challenge. I don't know if there's simply more room for evaporation or if the swings are bigger because the tank is bigger? At one point I blamed the salt but have since ruled that out.
Somehow an ATO has been the last thing to be added and I am hoping that helps reduce the swing. Having said that, the swing with ours is always up in salinity and thus I conclude always due to incorrect (lack of) top off.
We certainly know that evaporation happens at different rates on different days due to a variety of factors so it might well be that your constant RO drip is magnifying what is already a slight swing.
Regardless, it sounds like you're taking steps to try to remedy the problem and I sure hope they work! Best of luck to you and keep us posted!

 

[Whiterabbitrage]

Thank you. If I believed in such things, I'd say the tank is cursed. I can't even dose because the tank uses up things so strangely. Some days it uses lots of Alk, other days it uses none. I have to test every day before I dose. It's just been crazy.

 

[OrQidz]

Something's gotta be off - that's a huge change for a tank that size. Evaporation can definitely happen at different rates. Hot summer day, fans blowing, etc. But as others have pointed out, that's a lot of water to make that kind of change. How much does it vary day to day, if you aren't messing with it? Is it creeping up slowly and then changes when you do a water change? Could your tank be leaking somewhere? What's your set up like? Maybe we can help troubleshoot. Don't give up! There's got to be a way to fix it.

 

[bat21]

Is your tank located below your kitchen? Because with a small hole in the floor, all it takes is a box of salt with a small hole, right near a small hole in your cabinet right above that small hole in the floor, and boom, you've got salt pouring into your tank causing salinity issues. I've seen it a thousand times.