salinity for fish-only tank

[dreamreefer]

I'm wondering what salinity/specific gravity levels will start to be harmful for a fish-only tank? I've come across a tank with 1.032 spec gravity, i know its high for a fish only, but does it start to stress and kill them eventually?

[LRS078]

Too high a salinity and the fish can't drink enough to keep themselves hydrated. Too low a salinity and they can suffer renal failure for not having to drink anything to stay hydrated. Stick to the .020 to .027 range and you'll be fine. In the short term you can run far lower salinity but don't try to do it for years on end.

Hyposalinity can be as low as .014 or so but few take it lower. Salinity that low is usually a treatment for marine ick or similar and seldom goes on for more than a month or three.

In the short term .032 isn't going to kill anything most likely but I would start transitioning down to a normal range ASAP. A point to two points a day will not be a problem and the water changes never hurt anyone.... As long as you don't try to do it all in one day you should be fine.

Hope this helps....

[dreamreefer]

LRS,

it does, thanks a bunch...i assume a point to you means from 1.024 to 1.025? THanks again...

[D659600]

I have kept my FOWLR at 1.019 for years now and never had any problems. I belive that it real depends on the kind of fish you keep to.

[sophia101]

The general rule for FOLWR aquarium is 1.020-1.025...just to play it safe. IMO i wouldn't go much above or below this range. Just about all fish will thrive with that SG.

[Ironsheikh]

.023 --never had any problems

[46bfinGA]

i keep mine around 1.025 i have few starfish in there and from what ive read they prefer a slightly higher salinity.

[LRS078]

You are going to have a range of a couple points due to evaporation in the sump and resulting top off. So I'd benchmark for around .023. Fishy only systems you can keep lower salinity (.020) where inverts/corals/etc tend to like a bit higher salinity (.023-.026)

BTW, the lower you keep the salinity the cheaper your water change bill....

[Cash56]

I keep mine at 1.0215 to 1.022.

and I have snails, and nice shrimp, perppermint, cleaner, and fire.

I took a water sample into a store, adn they said it was too high, at 1.027.

When I got home, my own reading was 1.0245. I thought i had it at 1.022, but had added some salt water, and that must have changed.

I then purchased a new meter to read salinity.

My new reading, with the new Deep Six reader, was 1.0195.

My ocean systems meter read 1.0215, A +0.02 difference.

Then, I treid to test my water again, with another store, and again, the reading was different, 1.0185,

Then tested with another store, and my water there was 1.0235.

I almost decided to buy a calibated light lazer model, or what ever they are, that cost $60 to $90 or so, but instead, i jsut wnet back, ahdn HEDGED with my oldest Ocean systems meter, and returned the new deep six meter.

I try to keep it between 1.0215 and 1.0220. Thinking that if its 0.002 too low, its still at the safe range of 1.0240.

And If I'm 0.015 higher than the real reading, then its at the ok low end of the range, or 1.0205.

I have heard many people say, it doesnt mater much.

I THINK ITS VERY IMPORTANT, AND DOES MATTER A LOT!


What you need to do, is find out, if your reading is accurate.

You can have the water tested at several different store, with their testers, and you can buy a new one, to compare your new one to your old one.

(Dont forget, your old one, very well could be more accurate than your new one. So, you might want to return the new one after you compare it, or keep it, as a backup, to make sure your old one, is still reading close to what its supposed to. and you can use your old one, to make sure the new one, is accurate, or doesn't have some salt jammed it it, to prevent a good reading.)

When you finally do find what IS the right reading, in a fish only tank, you wnat to stay between 1.020 and 1.025. If you ahve some shrimp, ot keep the parasites off the fish (and the fish wont eat the shrimp), then you want to stay in the 1.0220 to 1.0250.

Hence, I try to under shoot a little, at 1.0215 to 1.0220, since my reader may be as much as 0.020 too low.

so, my 1.0216 reading may actually be 1.0230.

I dont think mine is too high, but if it is high by 0.0015, I'll still be in the safe low range bottom of 1.0200.

Since my shrimp are all doing pretty well, I think my reader is likely near accurate (better than a new one, that was 0.0015 low than my old one),

or it may be a little low, so my 1.0215 might actually be 1.0235. the latter, being very good for both fish and inverts.

What all this means, is, you need to find out what is the true read, of your instrument, ie, is it right, a little low, a little high, and fi off a bit, adjust for that, and try to shoot for 1.0220 to 1.0235.

Basically, that just tightening up the range a bit, from the standard 1.0200 to 1.0250 suggested target.

Jsut make sure, if yours is reading 0.005 too low, you dont try to keep it at 1.0250, the high end of the range, which woudl really be 1.0300, way outside the suggested level.

And vice verse, is you are too low.

So, in summary,

Find out if your reader is low, high, or right on,

then adjust that reading to read in the tight range of 1.0215 to 1.0235.

That should help your fish be healthy, and feeling and looking good.

Good luck.

[Cash56]

IF you reduce that 1.0320 rating back down to 1.0225, do it very slowly. VERY VERY slowly.

Some fish, like a powder blue tang, can be killed by changing the salinity too fast. Shrimp are also very sensitive to changes in salinity, temp, etc.

You might want to reduce it back to normal by only 0.010 per week (ten weeks to get it down to 1.0215) to be safe, if you have a sensitive fish like the powder blue, or shrimp.

[Ocicat]

Originally posted by LRS078
Hyposalinity can be as low as .014 or so but few take it lower. Salinity that low is usually a treatment for marine ick or similar and seldom goes on for more than a month or three.

Hyposalinity to treat ich is actually 1.009. Any higher than that probably will not kick the problem.

[dreamreefer]

Cash56,

regarding your problem with readings and erroneous meters...All you need to do is calibrate it with freshwater. Freshwater SG is at 1.00. I use my RO/DI water to test with TDS reading at 4ppm. Once calibrated to freshwater 1.00 SG, you can be sure of the saltwater reading. That'll save you some time from going to LFS and buying extra meters to test...IMHO...

Sj

[danorth]

I find that 1.025-27 works best for me and the higher salinity makes my skimmer work better.

[dreamreefer]

danorth,

i think it just makes your skimmer work harder if that's what you mean? if that's really true, that means there's more to skim at higher SG? according to LRS's comment up there, higher sg means the fish might not drink enuff to keep themselves hydrated, which means more waste to skim? 1.027 high be a little high IMO...

[danorth]

By work better, I mean that it produces a drier skim out of the water using the skimmers I have on the tank.

I can't say I personally know enough about fishand their biological systems to go either way about 1.027 and dehydration, but I understand what is being said. It never hurts to be safe and go to 1.025.

[I like Triggers]

I run 1.021-1.023 and everything is fine. If you keep it stable in a reasonable range, I think fish will acclimate to it fine. In my Marine biology courses I have learned the ocean currents are constantly mixing and I don't think it makes a large impact in the longrun. The area of the water where fish live is the most mixing part of the ocean, new waves and water are circulating constantly so I dont think there is a definite answer on what the best SG is.