Can't Raise Sg Level

[timmystood]

OK, so I have a Figure 8 Puffer tank and the tank currently sits at 0.4SG, I've tried really hard to raise it, i've added loads of salt over time, more than recommened by my LFS. How can I raise the SG!? I am using marine salts.

 

[nmonks]

What is 0.4 SG? 1.004?

SG will go up if you add more salt. Basic physics. But it is entirely possible your hydrometer is broken. So long as you are adding about ~5 grammes of sea salt mix to a litre of water, then don't worry about the SG in the short term. Your puffer can handle the variation between water changes. In the meantime, maybe you can test out your hydrometer with a glass of plain water and then in one made as salty was you can. Swing arm hydrometer sometimes gum up over time, and giving them a good long soak in warm water will help dissolve away any salt crystals bunging up the mechanism.

Cheers,

Neale

 

[timmystood]

Hi

Yeah, sorry I meant 1.004...

The hydrometer is brand new and I've only used it half a dozen times or so and each time the SG comes out at 1.004SG. I mean, from my understanding this is only just below the required SG levels for figure 8 puffers anyway, but ideally, I would like to raise it to about 1.008
The advice I receieved was 1 level teaspoon of salt per gallon of water. I did this the hydrometer wasn't even registering it, so since then, pretty much everyday i've added an extra 3-5 level teaspoon's of salt, meaning there is actually about 7 level teaspoons of salt per gallon.

 

[nmonks]

How heavy is a teaspoon of salt? Go weigh one in the kitchen. So long as you put in the right weight of salt per volume of water, you'll be fine. This _isn't_ accurate by any means, because an open box of salt absorbs water, so over time the weight of a teaspoon of salt actually includes a proportion of water instead of salt. But it's good enough for brackish water fish, which drop ice cubes down the back of the monster Accurate Salinity.

If the hydrometer doesn't work, take it back. Test it in fresh and salt water (35g/litre salt) and you should get 1.000 and 1.025-ish. If not, then it's a dud.

Cheers,

Neale

 

[kjharve]

Hi,

I've had pretty much the same issue. I have a tank which holds about 100 litres, I want it at 1.005. The box of salt I have says it will make 60 litres of saltwater at 1.025. So I worked out I need about half a box. I've added nearly all the box and my hydrometer still reads under 1.003!

I have tested the hydrometer in tap water and it doesn't reach 1.000! It sits under it!

My conclusion - it's knackered! And it's brand new!

Anyone thinks my calculation might be wrong or is my conclusion right?

Kev

 

[andywg]

Hydrometers are pretty inaccurate at the best of time, especially the swing arm type which give false readings if a bubble gets near the arm.

Accuracy is not as important in brackish as marine, though a refractometer only costs about £35 and that will give one that does not need re-calibration within 10 degrees of room temp. Not a bad price for piece of mind (though as mentioned before, the SG of brackish does not have to be an unchanging constant as it does in marine)

 

[kjharve]

Hydrometers are pretty inaccurate at the best of time, especially the swing arm type which give false readings if a bubble gets near the arm.

Accuracy is not as important in brackish as marine, though a refractometer only costs about £35 and that will give one that does not need re-calibration within 10 degrees of room temp. Not a bad price for piece of mind (though as mentioned before, the SG of brackish does not have to be an unchanging constant as it does in marine)

Is that the case when introducing new fish?

I have bought a couple of F8 puffers that are still in the LFS until my tank is ready. I want to bring the SG up to match what the puffers are currently in. Should I be overly worrying about this or not? What is an acceptable amount to be out do you think?

Kev

 

[andywg]

Nmonks may disagree here, but I would imagine that so long as the SG is not out by more than 0.005 between shop and tank water, you should be alright with a couple of hours or so drip acclimitisation (have the water from the tank drip into the bag at a rate of 1 drip per second through a knotted piece of airline).

 

[nmonks]

No he won't. This sounds fine to me. By their very nature, brackish water fish are built to adapt to sudden changes in salinity. I wouldn't worry about taking any brackish water fish from 1.000 to 1.005 in the space of an hour, and even going to full seawater should be possible within a few hours. After all, they are able to do this in the wild.

The problem is almost never the fish but the filter bacteria. Adapting fish to the salinity of the aquarium is easy; adapting the aquarium to a different salinity for the sake of a new fish is much more difficult. You should only change the salinity in an aquarium slowly, and monitor nitrites carefully througout. From fresh to SG 1.005 should be safe, but anything higher is likely to stress the filter bacteria.

Cheers,

Neale

Nmonks may disagree here, but I would imagine that so long as the SG is not out by more than 0.005 between shop and tank water, you should be alright with a couple of hours or so drip acclimitisation (have the water from the tank drip into the bag at a rate of 1 drip per second through a knotted piece of airline).

 

[kjharve]

I have now taken the little weight out of the plastic needle-indicator in the hydrometer, this was obviously weighing the needle down too much as the reading for tap water was well below 1.000.

I replaced the weight with a blob of blue-tac and added/removed bits of the blue-tac until it read 1.000.

Then, I used it read the water in my tank. It's up to 1.014 (if my new-fangled hydrometer is reliable.)

This kinda confirms my suspicions that the salt level was too high!

A new hydrometer should arrive in the post today so I will double-check the reading but, needless to say, I am already preparing some freshwater to dilute the saltwater a bit.