Salinity question

[FixIt]

So I bought a Red Sea refractometer and want to keep an eye on my water more actively but have a couple questions.

1. I know I want to keep my reef tank at 1.025 salinity but if I am at 1.030 or maybe a bit higher does that mean I am to low on water because of evaporation?

2. Do I need to get the salinity to a correct level before doing a water change?

All of the other parameters seem to be ok and I think I am past my uglies. Tank has been running about a month now.

Thanks for all the help.

 

[Ari_Ball]

Always to keep the water at 1.025

 

[Super Fly]

So I bought a Red Sea refractometer and want to keep an eye on my water more actively but have a couple questions.

1. I know I want to keep my reef tank at 1.025 salinity but if I am at 1.030 or maybe a bit higher does that mean I am to low on water because of evaporation?

Could be if there is no ATO (Auto Top Off) being used to replenish evaporated water with fresh RODI water.

2. Do I need to get the salinity to a correct level before doing a water change?

I would, it's ok to maintain level around 1.025-1.026
Also, please make sure the refractometer has been properly calibrated using a calibration fluid. This should be done weekly. FYI - temp of the refractometer should match tank water temp or close enough. If they are different by large amount, it will affect the reading.

 

[Waters]

So I bought a Red Sea refractometer and want to keep an eye on my water more actively but have a couple questions.

1. I know I want to keep my reef tank at 1.025 salinity but if I am at 1.030 or maybe a bit higher does that mean I am to low on water because of evaporation?

2. Do I need to get the salinity to a correct level before doing a water change?

All of the other parameters seem to be ok and I think I am past my uglies. Tank has been running about a month now.

Thanks for all the help.

If you started with a salinity at 1.025 and it is now reading 1.030 then yes, it is due to fresh water evaporating (or you have a TON of salt creep which is highly unlikely). You want to keep that number as stable as possible using an ATO or adding fresh water manually daily (sometimes more often depending on the size of the tank). Yes, you want your water change water to match the salinity of your tank water.

 

[PatW]

As water evaporates, it leaves the sal mix behind. Evaporation will lower the water level in your tank or your sump if you use one.

Some people mistakingly replace the volume with freshly mixed saltwater. In doing so they are adding additional salt to the same volume of water. In that kind of case, the salinity will creep upwards.

One needs to replace the volume lost to evaporation with the purest fresh water one can get. The best option is usually RODI water.

If the salinity is low, it can be slowly raised by topping off with salt water. If the salinity is high, it can be lowered by removing a small volume of water and replacing it with RODI water.

 

[FixIt]

As water evaporates, it leaves the sal mix behind. Evaporation will lower the water level in your tank or your sump if you use one.

Some people mistakingly replace the volume with freshly mixed saltwater. In doing so they are adding additional salt to the same volume of water. In that kind of case, the salinity will creep upwards.

One needs to replace the volume lost to evaporation with the purest fresh water one can get. The best option is usually RODI water.

If the salinity is low, it can be slowly raised by topping off with salt water. If the salinity is high, it can be lowered by removing a small volume of water and replacing it with RODI water.

So is over the 1.025 high or low salinity? I am confused about the numbers and the direction they go and correspond with salinity.

 

[Reefer Deez]

If your over 1.025 then the salt is too high and you would need to and some fresh RODI water to balance it out. Are you using 2 part dosing? If so when you change your water you might want to have the salinity a bit lower like 1.024 so when you dose alkalinity and calcium the salt will balance out. A good auto top off will keep the balance of evaporating water and salt.

 

[FixIt]

If your over 1.025 then the salt is too high and you would need to and some fresh RODI water to balance it out. Are you using 2 part dosing? If so when you change your water you might want to have the salinity a bit lower like 1.024 so when you dose alkalinity and calcium the salt will balance out. A good auto top off will keep the balance of evaporating water and salt.

I have a Coralife LED Biocube 32 and am not dosing and do not have a ATO. I think a ATO is my next purchase however. Any advice on a ATO that wont break the bank for a beginner?

 

[Reefer Deez]

Sorry I don't know of hand my tank came with a really small reservoir for an ato you won't need much.
You need a small container if it's designed for an ato it should have a tube and a float for gravity feed or you can pick up a tunze ato, if you have an apex controller you can get the apex version.
Or it's not as accurate but you could do the top off yourself every day.
I have a smaller 50 gallon system and I just top off every night and my fish and coral are happy.but it's not as balanced as the tank that came with the ato.

 

[Waters]

Do you have a sump? What size tank do you have? You can add the fresh water manually by just marking the water level on the tank (if you don't have a sump) or on the sump in the return pump section. I normally use a small piece of electrical tape. Just keep the water level at the tape by adding fresh water as needed. If you do want it automated, Tunze makes really good stand alone ATOs for all different sized tanks.

 

[tiggs]

I have a Coralife LED Biocube 32 and am not dosing and do not have a ATO. I think a ATO is my next purchase however. Any advice on a ATO that wont break the bank for a beginner?

Both Tunze and Smart ATO make good products that won't break the bank and will fit inside a Biocube rear chamber

 

[theKoolAidMan]

So is over the 1.025 high or low salinity? I am confused about the numbers and the direction they go and correspond with salinity.

Depends on how high over. For a reef tank, the general acceptable range is from the low 1.020's up to about 1.027, with most reefers running at 1.024 or 1.025. There are some exceptions based upon what livestock you're keeping. The higher the number, the saltier the water is. If you're at 1.026 or 1.027 most of the time, It's not some emergency and things aren't going to start dying because of it, but most folks would advise trying to get that closer to a stable 1.025. 1.030 is too high, however and while you're likely not going to see stuff start dying, it can start to stunt coral growth, and higher salinity is tougher on the fish. The reason we keep reef tanks at 1.025 is really for the corals, which prefer it. Most evidence suggests it's easier on the fish at much lower specific gravity than that, which is why systems with only fish and rock and no coral run their salinity quite a bit lower than reefers do. The main reason high salinity can be bad for the fish, especially is because the higher the salinity, the less dissolved oxygen in the water which the fish need to breathe.

 

[CindyKz]

So is over the 1.025 high or low salinity? I am confused about the numbers and the direction they go and correspond with salinity.

As the number goes up, the salinity goes up. 1.025 - 1.026 is your target. If the number is above 1.026, the salinity is too high ie there is too much salt in the water. If the number is below 1.025 the salinity is too low, ie there isn't enough salt in the water.

Make sure you get some refractometer calibration fluid and calibrate it frequently. Personally, I check the calibration on mine every time I use it. Others check once/week.

 

[chipmunkofdoom2]

1. I know I want to keep my reef tank at 1.025 salinity but if I am at 1.030 or maybe a bit higher does that mean I am to low on water because of evaporation?

2. Do I need to get the salinity to a correct level before doing a water change?

1. A specific gravity measurement of 1.030 is high for a reef tank. Does that mean you are too low on water? No, not necessarily. There are plenty of other ways that salinity can become high aside from evaporation. However, if you have not been topping off with freshwater, then that is a likely cause of the high salinity. If your salinity is high, you need to add freshwater to bring it down, whether you are low on water or not.

2. Not necessarily. An ideal water change should match your tank's parameters as closely as possible. I personally match on salinity and alkalinity, but some people choose to match more. If you mix up saltwater to 1.030 SG (S = 39ppt), then there is likely little difference between the water you take out and put in. This would be unlikely to negatively affect the animals in your tank.

Personally, I would not change water until I have the salinity under control. Drop the salinity by 1 ppt or less per day until it is around 35 ppt (1.0264 SG), then do your water change.

 

[Captain Quint]

As water evaporates, it leaves the sal mix behind. Evaporation will lower the water level in your tank or your sump if you use one.

Some people mistakingly replace the volume with freshly mixed saltwater. In doing so they are adding additional salt to the same volume of water. In that kind of case, the salinity will creep upwards.

One needs to replace the volume lost to evaporation with the purest fresh water one can get. The best option is usually RODI water.

If the salinity is low, it can be slowly raised by topping off with salt water. If the salinity is high, it can be lowered by removing a small volume of water and replacing it with RODI water.

+1. Did you perhaps topoff with some saltwater at some point?

It is not a dire ememgency so you need not ruch a sudden drop. You could replace perhaps a gallon a day of the saltwater with RODI fresh until you get back to ~35%

 

[Super Fly]

Any advice on a ATO that wont break the bank for a beginner?

I use this ($38) http://autotopoff.com/Standard/index.html with an Aqua Lifter pump ($27) https://www.bulkreefsupply.com/aqua-lifter-vacuum-pump.html FYI - the float should be cleaned once in a while to prevent mineral build up and avoid getting stuck. For the water reservoir, I use an old 5-gal spring water jug.

 

[Captain Quint]

Always to keep the water at 1.025

Ari_Ball, why is that my friend? it is good to keep stable and yes 1.025 is good. Please explain why 1.025

Many keep lower or a tad higher and I'm curious as to the rationale behing the '1.025' post. Thanks.

 

[Sailingeric]

Mine is around 1.023-1.024, gives me a little wiggle room if the ATO runs dry or if too much water gets in the sumps.

 

[Ari_Ball]

Ari_Ball, why is that my friend? it is good to keep stable and yes 1.025 is good. Please explain why 1.025

Many keep lower or a tad higher and I'm curious as to the rationale behing the '1.025' post. Thanks.

Cause the seawater is 1.025???

 

[Forsaken77]

You don't need to get your water to the correct salinity before doing a water change. You can compensate for that with the salinity level of the new saltwater. You may be +/- .002 off from 1.025, but that's rarely something to worry about and can be fixed in the next change or add or lower the level of water in the sump if you like.

I keep my salinity at 1.024 so any evap doesn't have a dramatic affect. I also refill top off water manually though.