Specific Gravity

[J19Reynolds]

After u do a water change how long should u wait to check the SG? Mine before was 1.020

 

[ccCapt]

You should check the salinity of the new water before it's added to the tank and it should match what's in the tank unless your trying to raise or lower the tank salinity. But anyway, you can check it a few minutes after you finish the water change. 1.020 is way too low. Should be 1.026.

 

[J19Reynolds]

I knew was too low Thats y wanted do water change ... I didn't check it after bc didn't know and forgot this morning but it's always been at 1.024 since its been running.... I'll check as soon as get home and see if it went back up

 

[Tmyboy]

You should check the salinity of the new water before it's added to the tank and it should match what's in the tank unless your trying to raise or lower the tank salinity. But anyway, you can check it a few minutes after you finish the water change. 1.020 is way too low. Should be 1.026.

I don't think you'd get an accurate reading after "only a couple" minutes after the PWC. I wait at least an hour before rechecking salinity and then adjust. I keep mine between .024 and .025

 

[Smudgy35]

I keep mine at .023 and that seems fine, is this too low?

 

[Zer0]

I agree. I would wait a couple hours after you just mixed the saltwater to test the salinity. Checking right after you've added the salt won't be very accurate I would think.

 

[Tmyboy]

I agree. I would wait a couple hours after you just mixed the saltwater to test the salinity. Checking right after you've added the salt won't be very accurate I would think.

I was actually referring to after you put the water in the tank and then test the tanks salinity.

As far as mixing the actual water to be used in pwc....I drop a couple powerheads in the bucket and let it mix for 24hrs. I definitely wouldn't mix water and then use it after only a couple minutes or even 1 hour. All the salt wouldn't be dissolved and your reading would more than likely be low.

 

[Zer0]

Oh yeah, that too.

 

[J19Reynolds]

I buy my water pre-made from my LFS

 

[MacDracor]

Ok, so here's my understanding of the situation. If you check the SG right after mixing new water, you can get a false high reading because of bubbles from the mixing. A couple hours will probably sort that out. After adding the newly mixed water to the dt, I always wait an hour to be sure it's been thoroughly mixed into the tank's water, though I'm probably being conservative. With good flow, it should be mixed in pretty quickly.

 

[Gregcoyote]

The bubbles don't do much as long as you are using a refractometer...but most salts take a bit to fully dissolve. I make up 50 gallons at a time and the salinity goes up over the first hour as the salt all goes into solution using a power head to keep it stirred up. I sure suggest going at least 4-6 hours before using it. When adding to the main system, I wait at least an hour before checking the total salinity.

 

[ccCapt]

Unless you have absolutely no water movement inside the tank, all the new water should be mixed with the old in a few minutes and the salinity established. The new water doesn't stay seperate from the existing water.

 

[J19Reynolds]

How do u get SG to go up other than pwc

 

[Leighton79]

Let your water evaporate without tipping up with RO.

If you don't understand the concept...,, dump a cup of salt in a bucket and fill with water, let's say it's 20ppt, let half the water evaporate that will make it 40ppt.
When the water evaporates the salt stays in the vessel.

 

[Leighton79]

Tipping = topping. My bad.

 

[ccCapt]

How do u get SG to go up other than pwc

When you lose water from evaporation don't add freshwater, add saltwater.

 

[J19Reynolds]

When you lose water from evaporation don't add freshwater, add saltwater.

Ok thank you that sounds better and more understandable bc I buy my water I don't have any salt on hand.. Or is marine buffer salt?

 

[Gregcoyote]

No..buffer is not salt. It is used to buffer ph swings. Like a shock absorber. Your KH reading show the amount of buffering your water has.
In reefs, this is commonly added with a calcium supplement when wanting to grow Stoney corals.

Be careful of correcting salinity too fast. Use RO/DI for evaporation. When doing a water change check salinity. If it needs to be raised, use replacement water with a small amount higher or lower salinity as needed. I emphasize tiny amounts. For example, if your tank is showing 1.023 and you want to adjust over a few days to 1.025, make your replacement water (20% or so total volume) go in at 1.024, then 1.025 next time and monitor. Do not throw raw salt in the sump. To lower salinity, you can do the reverse. As said above you can also adjust salinity up by topping off with saltwater and monitoring every time.

 

[melosu58]

but most salts take a bit to fully dissolve.

Exactly. Bubble dont have much to do with it but the time that it takes to dissolve fully does.