Water level in sump - evaporation

[stan450z]

Would it be better to keep less or more water in a sump or is there no effect in regards to evaporation? Would like to figure out a way to limit the rate of evaporation. I usually have to top off 1g of distilled water in my 75g with every 3-4 days. Would like to do less of those. And of course I have a Chiller and keep my temp set at 78 degrees. Here is my current water level. I leave about 5 inches now when before it would be around 4. Height of sump is 16 inches.

 

[Sniperhank]

You want to keep your water level as stable as possible to keep salinity stable.
It would also depend on the size of the sump and display in terms of a power outage and how much water will reside in the sump when this occurs.
Considering the water level is also important for your equipment when it comes to the water level they need to run correctly.

 

[Nils]

That's why you have an automatic top off system....

 

[Dary421]

hank hit it right on the nose when it comes down to losing power and having the main tank drain back into the sump,..you do not want it to overflow the sump and end up as a major mop up,...the ato is probably one of the best investments you can make for your tank,...it'll always keep you water at the proper level and the salinity stable,i personally use one of the tunze models but its just a personal preference as to what you get.

 

[54seaweed]

your lucky if you get evap every 3/4 days , I get about a inch a day equal to about a gal .
I have a gravity fed top off tank recently been trying to figure out a good place to mount it rather sitting on a stool like it presently is, I use a toms top off system I got it real cheap on a discount rack , refilling evap gets old . my sump is 30g and main is 90g .

sump size is recommended to be at-least 1/3 size of the main . I keep it at a level of 8 to 10 inch . if power goes out only a set amount of water will fill sump with no over flow
it took me a few times to set the overflow box to drop aprox 10g leaving about another 10g of empty tank ,

I had my fill of water overflows not fun to clean up glad I own a carpet cleaner and wet vac,