Getting the Specific Gravity just right

[evw2k]

I bought a large bucket of instant ocean salt and followed the directions on the bucket. I added the salt to the sump and after a day or so it was all disolved. I calibrated my floating hydrometer thing and the specific gravity was only 1.021 I need to get it up to 1.025 put the directions don't say how much to add.... I have 50ish gallons of water, and I think the directions said 1 lb of salt for every 5 gal to reach "optimal sg". According to directions optimal sg is 1.021, but I need 1.025. How much salt should I add now????

[ek9vboi]

Don't follow the bucket I guess. lol j/k, the instructions on back are exactly that to mix "optimal" range. keep in mind IO is for a fish only type of tank and "not so much" for reef, which would explain why they have RC for reef aquariums.

Anyways, I used a small digital scale to measure the amount I mix with my ro/di water. For 5g it would take 1.655lbs of IO salt. So far its been dead on EVERY TIME I mixed a new batch.

Since you have 50gals already mixed up, just add 1/2 cup and see where that takes you. Keep on adding until it gets to the targeted salinity.

Also, get a refractometer. Its well worth the money and you can test it after a few mins. Or thats how I do it.

[Billybeau1]

Yes, a refractometer is the ticket.

When I was using IO, it took about 3/4 cup per gallon to get to 35 ppt or 1.0265

Don't get frustrated. You'll get the hang of it with practice.

[davidryder]

Just add a little at a time... after enough water changes you will know almost for certain how much to add to each bucket of water.