How do you determine how much to top off?

[ciao]

I'm curious to know, how do most people know how much to RO/DI water to put back into their system to make up for evaporation? It seems kind of tricky since too much water and the salinity plummets and too little water the salinity would shoot up......just trying to figure out a good rule to go by.

[jgf86123]

ciao, the way i work it is this, i keep my water at a certain level, and when i top it off, i fill it back to that level, that way im pretty much guaranteed to keep my salinity as stable as possible.

 

hth

 

mick

[CA2OR]

Best way is to turn off your return and let sump fill....then add water to max acceptable level and turn on pump again....mark where water level drops to and fill to there from here in. This will keep your Salinity at the same level all the time as salt doesn't evaporate.

[ciao]

Thanks. I think I'll use that sump method.

[pledosophy]

I use the same sump method Eric describes, but I turn everything off for it, skimmer, filters, everything that could add water to the sump. I simulate a power outage.

 

When I mark my fill line, I give myself an extra inch, because sometimes when I was refilling water by hand, I was heavy handed with the jug.

 

I use an Auto top off unit now so I only have to add water to my resivoir tank once every two weeks. It's quite nice.

 

HTH

[Lowman]

If you are using the 'bulk" method, the first thing you should do is test your specific gravity. Then test it again an hour after you add water to make sure it is at the optimum level

[Rick]

As pledosophy explained you want to simulate a complete power outage. Let everything drain out of the system. Then go ahead and fill it up to where you feel is a safe level. (Allowing an inch or so is a good way to make sure) Then fire everything back up and mark that point on the sump. I use a strip of duct tape as there is less chance of rubbing the mark off. Keep in mind when doing water changes to allow for the salinity to rise as the water evaporates. For instance I shoot for about 1.025 when my system is full and then as it evaporates the salinity rises to about 1.026. I add 5 gallons every two days with a total system volume of about 190g. Using an ATO is even better but keep in mind the upper limit. Another thing you may consider with a topoff is to lower the upper level by the size of your topoff system. I.E. If you have a 5 gallon topoff then lower the level by 5 gallons. Doing this provides enough room to handle the extra water when(if) the topoff fails.