Sans PWC, what can affect (lower) the SG of a tank?

[Mr. Limpet]

Can my sand, canister filter, or something be absorbing the salt and causing the SG to drop? The tank is cycled and about a month old, I use Instant Ocean and a refractometer.

TIA

 

[Henry405]

I notice my salt drops and its prob due to my HOB splashing. My tank is currently hoodless with the light sitting on the trip and theres a layer of salt on it. Also anywhere that is in contact with the water evaporation lowers the water will have a layer of salt. Ex. cords running out of tank

 

[Gubernaculum86]

I cant think of any other way to lower SG other than doing top offs with RO/DI and small PWCs.
I'm just getting my SG under control in my 55. It's been high for a really long time around 1.028 to 1.030. With no ill affects to my fish. But I decided it was time to get it under control. It didn't take that many PWCs to get it down. Over about 2 weeks I've changed out about 7 gallons of SW for RO/DI and it finally got down to 1.025 yesterday.

 

[Mr. Limpet]

I notice my salt drops and its prob due to my HOB splashing. My tank is currently hoodless with the light sitting on the trip and theres a layer of salt on it. Also anywhere that is in contact with the water evaporation lowers the water will have a layer of salt. Ex. cords running out of tank

I have a glass topper and other than one spot on it that looks like a hard water stain, I don't see any salt caking anywhere. I'd figure any evaporation would raise the SG, but I don't see any water loss.

Thanks!

 

[Mr. Limpet]

I cant think of any other way to lower SG other than doing top offs with RO/DI and small PWCs.
I'm just getting my SG under control in my 55. It's been high for a really long time around 1.028 to 1.030. With no ill affects to my fish. But I decided it was time to get it under control. It didn't take that many PWCs to get it down. Over about 2 weeks I've changed out about 7 gallons of SW for RO/DI and it finally got down to 1.025 yesterday.

That's one thing that concerned me is if I keep adding salt without a PWC, that all the sudden I'm going to get a jump in SG.

 

[iDream]

Evap would only increase salinity, the only thing I could think of would be an ATO malfunctioning.


I would definitely advise against adding salt to the tank if you have fish in, it's not good for them. If anything just top-off with some saltwater with a lower salinity to raise it slowly

 

[Mr. Limpet]

Evap would only increase salinity, the only thing I could think of would be an ATO malfunctioning.


I would definitely advise against adding salt to the tank if you have fish in, it's not good for them. If anything just top-off with some saltwater with a lower salinity to raise it slowly

Yep, I pull 5g from the tank and mix it up, then add it back. I don't have a sump or ATO attached, just a 305.

 

[iDream]

I've almost never heard of SG dropping, usually it's increasing


Only other advice I can give is keep that canister clean, you could end up with nitrate problems really fast if not

 

[Mr. Limpet]

I've almost never heard of SG dropping, usually it's increasing


Only other advice I can give is keep that canister clean, you could end up with nitrate problems really fast if not

That's what I thought and I didn't want to try and keep the SG level and then have it skyrocket. Yep, keeping a close eye on all parameters, but thanks for the heads up on the no3.

 

[Henry405]

where is your SG currently at?

 

[Mr. Limpet]

where is your SG currently at?

The current SG isn't really the issue, it's where (why?) the salt is disappearing too. I wasn't sure if maybe the DSB, fresh filter media or something else is absorbing the salt and until it's seeded with salt, the SG would keep dropping.

I just figured that if an SG is reached, it should stay there until it's influenced by evaporation (raising SG), top offs (lowers SG), or if I do a PWC and maybe get the IO mix slightly off on the new water (SG goes up/down).

 

[iDream]

None of those are reasons why you're salinity would just lower, btw I hope your letting that bucket you take out to add more salt mix for about 24hrs, it needs to completely dissolve or the salt could burn any fish you have.

 

[yetee]

when you mix up your PWC's are you letting them sit for 24 hrs? I ask because you can get false readings before the salt is completely dissovled. do you have a skimmer? Those can lower your SG a bit if you are running it wet as well.

 

[Mr. Limpet]

None of those are reasons why you're salinity would just lower, btw I hope your letting that bucket you take out to add more salt mix for about 24hrs, it needs to completely dissolve or the salt could burn any fish you have.

It takes 24 hours to dissolve? I wish they would've put that info on the box! I use a air stone and power head to churn/aerate it for 15-20 minutes and figured that would be more than enough.

Thanks for the heads up iDream

 

[iDream]

Oh most definitely, even in emergency situations you'll want to wait at least a few hours before adding it back.

Good mixing setup though!

 

[Mr. Limpet]

Oh most definitely, even in emergency situations you'll want to wait at least a few hours before adding it back.

Good mixing setup though!

Thanks on the setup.

I'm betting you just hit on why the SG is so unstable. So I should churn/aerate for 24hrs and probably add a heater to the bucket too?

I guess these instructions are not to be followed, since that last part is what I thought I was doing lol:

"Stir vigorously to mix salt and water. Although the solution of Instant Ocean premium sea salt can be used immediately, we suggest aerating the water until it reaches oxygen/carbon dioxide equilibrium."

 

[Mr. Limpet]

when you mix up your PWC's are you letting them sit for 24 hrs? I ask because you can get false readings before the salt is completely dissovled. do you have a skimmer? Those can lower your SG a bit if you are running it wet as well.

I'm guessing, but the 24hrs which IO doesn't tell you about is the issue. No skimmer yet.

Thanks!

 

[iDream]

Probably a good idea, just leave the PH and airstone and put in the heater to temp match for 24hrs.

Start that for a few days and report back, we'll figure out where to go from there

 

[Chisel]

I'm guessing, but the 24hrs which IO doesn't tell you about is the issue. No skimmer yet.

Thanks!

It's pretty much a general (unspoken) rule of thumb to follow with all salt mixes.

 

[Mr. Limpet]

Probably a good idea, just leave the PH and airstone and put in the heater to temp match for 24hrs.

Start that for a few days and report back, we'll figure out where to go from there

Thanks for the help, I'll let you know how it goes. Gonna have to get a bigger bucket, that's for sure .

It's pretty much a general (unspoken) rule of thumb to follow with all salt mixes.

Unspoken is right lol. If IO would've at least made that part of the suggestion in the instructions, I would've done it. I though I was going overboard with my setup as it was (well my GF does anyway ).

Thanks!