How to top off?

[ferchoz]

My water evaporates very fast since I dont have a top (read it was better this way). I tested my salinity and its a little too high and my LFS told me to top off my tank using fresh water not salwater... Right now I top off my tank with Saltwater I buy from my LFS, I wanted make sure I am doing the right thing when topping off my tank since my LFS have given me wrong information in the past.
Thank you.

 

[HN1]

That is correct. The water evaporates and the salt etc. doesn't. That's why your SG rises. Use RO from the LFS if you don't make your own. Are you checking your salinity with a hydrometer or refractometer?

 

[ferchoz]

They use a Refractometer.. and excuse my question, I know what RO water is, because I've buckets of R/O water in my LFS LOL, but whats the benefit of it vs. buying just fresh water (for freshwater tanks)??? since RO water is more expensive

 

[HN1]

RO/DI is pure (should be as close to 0 TDS as possible) and gives you a known starting point. Regular FW contains a lot of stuff that won't cause major issues in a freshwater tank, but can in a SW tank.

 

[ferchoz]

So you recomend not to use FW???

 

[jessicasmarine]

In SW its best to always use RO/DI because all the impurities are out of it. Regular tap water contains anything from phosphates, nitrates, to chlorine, chloramine, distillates and a plethora of other chemicals and organisms. The RO water, as said earlier gives you a clean slate with every top off/PWC.
Use FW just preferbably fresh RO water.

 

[CementShoes]

RO water is further purified FW (if you will). You are trying to relate to terms in a way that is incompatible with their respective definitions.

Think of it this way.

Freshwater : Water without salt added to make salt water (be that tap water, well water, RO water, RO/DI water)

Saltwater : Freshwater with salt added.

RO Water : Freshwater that has been further filtered (not to be confused with filtered water) to remove all solubles making it pure H2O and nothing more. No addtiives (iron, chlorine, nitrates, phosphates , etc).

You use Freshwater to make both and RO, RO/DI is preferred for saltwater tanks.,

 

[joy13]

RO water helps keep the algae down since there is not phosphates in it for the algae to feed off from.

 

[austinsdad]

Do not use SW to top off!! The evap makes the salinity go up. Adding more salt water creates even more of a problem on top of that. And belive me, those swings in salinity WILL cause your inhabitants stress. Stress leads to sickness. Sickness can lead to death.

 

[jessicasmarine]

I learned the hard way. Mixing 5 gallon buckets of SW at 1.024 and adding about a gallon a day to my DT. Checked my salinity a week later, 1.029. Didnt even think about salt not evaporating

 

[thincat]

So you recomend not to use FW???

RO/DI water is FW that has all the impurities removed. Always top off with Freshwater.
You might want to check out the ATO(autoTopOff) unit at Autotopoff.com to automate your system.