Confused about salinity level

[GallonsOfFun]

So, it's supposed to take 1 cup of salt per 5 gallons of water to raise the salinity by .005, correct? Thus, in a 55 gallon aquarium it should take 11 cups of salt to reach 1.005.

I have put approximately 5 cups of salt in my 55g and my salinity is 1.005.

I know hydrometers are calibrated to read salinity at a certain temperature (I have the Coralife DeepSix Hydrometer) but online it says it's "designed to give temperature-corrected readings in warm water aquariums" and my water is 78F so I doubt thats the issue.

I'm trying to figure out how many cups to add back in (yes, I premix it) at the next water change (50% pwc), help greatly appreciated!

 

[coralbandit]

I believe that I add 2 cups of reef crystal salt to 5 g of water to get full strength marine water 1.025
1 cup for every 5 g should get you in the 50% marine area IMO.(1.011 ish)??
5 cups in 55g sounds like 1/4 of full marine or 1/2 of brackish??? aprox....

 

[Reefing Madness]

Hydrometer is probably never going to give you the same reading.
Marine Aquarium Basics, Part 1: Water and Salt

Preparing Artificial Saltwater | DrTim's Aquatics

 

[GallonsOfFun]

I know they're not terribly accurate but I don't think I have a need for a refractometer at the moment. When I go full salt I'll probably get one.

So just to be certain, I did another reading today and it said 1.005-1.006. So when I do my 50%pwc I should add back in roughly 2.5 cups of salt, correct?


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[coralbandit]

Are there fish in this??
Why are you changing 50%?
Fresh water bacteria and marine/brackish bacteria are not the same so the sooner you get your water right the sooner bacteria can get established....

 

[GallonsOfFun]

Yes, Green Spotted Pufferfish. I'm changing 50% because that is what's required weekly due to their huge bio-loads.

Full marine is an eventual thing for this tank. They arrived (wrongly so) in freshwater, so I am slowly raising the salinity to a mid-level brackish (1.010-1.015) for a while and eventually I'll take the tank to full marine. If I raise the salinity by much more than .002 per week, it'll kill the bacteria.

Sorry, that was a mouthful! But as for the cups of salt, would I be correct in adding 2.5 cups to maintain 1.005 salinity? Thanks for your help!


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[coralbandit]

The bacteria is going to die is what I was saying...
Brackish/marine/and freshwater are different.
I hope ReefingMadness chimes back in.
You should be able to get your puffer in water you want in days if not just one IMO.
You are going to cycle eitherway.

 

[GallonsOfFun]

The tank is fully cycled and I've been raising it like this for 2 weeks. I understand that the bacteria dies but the .002 per week allows time for the new bacteria to grow. This is an established method that many puffer owners use, it's not something I've just made up.


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[GallonsOfFun]

If I raised it to 1.015 right now, the bacteria would all die and it would cycle. If I raise it by no more than .002 a week, it won't cycle again.


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[Reefing Madness]

Theres absolutely no reason to change 50% of your water weekly with just a Puffer, no matter what you've read about. I had a half grown Porcupine in my tank.
Your thought process on raising the SG is good, you should be fine that way, but in no way would I change 50% of your water anymore.
At the SG your at now, throw a Skimmer on there now, that will keep your water clean for you. It will work better once your above 1.009, but it should produce something.
Or throw a mechanical filter on there until you get the SG above 1.017

 

[GallonsOfFun]

I have two GSP's in there, are you sure? All of the articles over at ThePufferForum and all of its members would attest to 50% pwc's. I don't see the danger in doing so (aside from spending too much on salt!), I make sure to keep salinity, pH, and temp constant.

What do you mean by mechanical filter? I'm running a Fluval 306 and also have a powerhead in the tank.


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[Reefing Madness]

Your Fluval 306 is a mechanical filter. Just fill that thing full of pad media to catch the messies from the fish.
I had a predator tank, Lion Fish, Spotted Grouper, Puffer, Snowflake Eel, I never went out of my way to change the water, especially 50%.
Keep an eye on your Nitrate levels, if they spike above 30, then your doing 25% water changes. Test weekly, You can keep the Nitrates lower, But I'd not let em go above 30, your just asking for trouble after that point.
Still, ya might want to think about a Hang On Back Skimmer, some really good ones for your size tank, that would help you big time.

 

[GallonsOfFun]

I suppose I'll just have to keep an eye on all the readings and before long I'll have a good idea of what % pwc to do. Need to check nitrate this week but ammonia and nitrite are at 0, as of yesterday.

Couple more questions while I have you:

1.) I took the carbon out of the top stage of the filter because I'm treating them with Melafix (nipped fins when I got them) at the moment - and because carbon stops working after a while anyway. What should I replace it with? There are two filter pads in there that were under the carbon, should I add something else?

2.) Cant find the answer anywhere online, but as I transition to marine (might just go straight there without stopping), I'd like to get live rock in as soon as possible. What's the minimum salinity it can survive in? And is there a salinity where I'd need to take the Fluval out at?

Sorry for all this but thanks so much you're a big help!


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[GallonsOfFun]

And wow, nice tank! What size? I'm sure you would've been going out of your way to do 50%'s if those were freshwater fish!!


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[J.Mcpeak]

Yes, Green Spotted Pufferfish. I'm changing 50% because that is what's required weekly due to their huge bio-loads.

Full marine is an eventual thing for this tank. They arrived (wrongly so) in freshwater, so I am slowly raising the salinity to a mid-level brackish (1.010-1.015) for a while and eventually I'll take the tank to full marine. If I raise the salinity by much more than .002 per week, it'll kill the bacteria.

Sorry, that was a mouthful! But as for the cups of salt, would I be correct in adding 2.5 cups to maintain 1.005 salinity? Thanks for your help!


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Use scales, I add 6gram per litre to get 1.005/1.006, cheap 0.0 (one dec place is good enough!)
A refractometer doesn't read that low. From memory, I think they start registering on the scale at about 1.016.

I've been doing it that way since I started with brackish, it takes all the guess work out!

 

[Reefing Madness]

My tank is 240g, 8x2x2.
Salt water fish are harder to keep than fresh water. You keep an eye on the water parameters, and your ok. No one, not even the guys that keep full blown reefs, or keep sharks do 50% water changes. Unless they are trying to get phosphates or nitrates down fast.

 

[GallonsOfFun]

Well in saltwater, no. But freshwater/brackish owners do much larger water changes than saltwater because they don't have the live rock and such to help filter.


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[GallonsOfFun]

Use scales, I add 6gram per litre to get 1.005/1.006, cheap 0.0 (one dec place is good enough!)

A refractometer doesn't read that low. From memory, I think they start registering on the scale at about 1.016.



I've been doing it that way since I started with brackish, it takes all the guess work out!

Thanks! I'll try that.


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[J.Mcpeak]

Thanks! I'll try that.


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No worries, thanks for the thanks!