Salinity Question

[fishman]

This is a dumb question but Im having issues with this...I think I know the answer but want to be sure.
Im changing tanks from a 125 to a 100. But due to a leak in the 125, I only have about 90 gallons of water in it. BUT I built a 40 gallon sump to go under the new 100 gallon tank that everything will be transferred to. So basically I will be about 40-50 gallons short. Do i just make up this 50 gallons with saltwater? Reason I ask is wont this increase the salinity of 90 gallons going into the 100 gallon tank? In the 90 gallons I am running right now in the leaking tank, the salinity is 1.025 and the new 50 gallons I have made is the same salinity...I just dont want to screw up on something easy like this. hope this makes sense...

 

[bound_for_obx]

If I understand your question correctly, you are adding more volume overall to your system. Make up the difference with saltwater of the same specific gravity. Are you getting confused because you normally do top offs with fresh water?

 

[Corty]

If you use a certain amount of salt for a 20 gallon, that same amount will not be enough to keep the same specific gravity for a fifty gallon.. You'll want to mix the 40-50 gallons to the same specific gravity as the rest of the tank.

 

[fishman]

Yes I think you both understood me. Im adding more water volumn...I have right now 90 gallons of operating water so speak. I need another 50 that is to be added to have enough for the new tank and new sump. So in essence Im going from a 100 gallon to a 150 gallon...(for round numbers sake). And yes the new SW Im making will be the same SG as the operating water. i think Im getting confused with adding SW and the top off process... I have 50 gallons in the making at 1.025 and the operating water is 1.025 as well. Guess i was right but wanted to be sure.

 

[crage34]

if u make the 50 gals u need to make up for the lost water the same sg as the water u already have u will be just fine