Advice on SpG, temperature please..

[Brad]

Based on what I've heard from this group, I've raised my tank to 80 degrees F. Now, I'm thinking that my salinity isn't high enough.

What should a SpG reading at 80 degrees be? I'm now thinking that it should be around 1.0235. That would give me a salinity of 35.

 

[steve-s]

What should a SpG reading at 80 degrees be? I'm now thinking that it should be around 1.0235. That would give me a salinity of 35.

It would depend on what instrument you are using to measure the salt content. A swingarm hydrometer will often read a little higher so 1.023 @ 80° would be fine. If using an ATC refractometer, then no need for a temp correction. Just shoot for 35 ppt.

Cheers
Steve

 

[jamal-188]

I keep my tanks 80F and 1.025 SG.

 

[pecan2phat]

Question on temp: since joining the AA forum, I have acquired a lot of good advise and techniques & I thank everyone for for this BUT, every book that I have read from Tullock to Fenner have suggested water temps from 75 to 78 degrees. They advise that a high temp will cause much less saturation of oxygen in the water & a higher metabolism thus causing a higher production of waste & sometimes aggression behavior.
What do AA members think about this? Just curious cause I use to keep my mini-reef tank @ 76 degrees & my FO tank @ 77 degrees. I've had these temps for many years with no ill effects but have raised them to about 79 degrees since joining this forum. The more reference books I read, the more I'm tempted to lower the temps back.

 

[WarOrks15]

yes that is a problem but you you are moving the water around and get the surface to get some waves or some thing your 02 levels should not drop that much. i was have a sump on my tank and i took out all of the bioballs and doing this the water has to fall and splash in the bottom.

 

[steve-s]

If you check the copyright dates of those books, they where written some time ago. Not many years ago, the lower temps where still recommeneded though. SW holds very little O2 in the first place and lower temps are employed to allow for more O2 saturation 77.4° being optimum. Considering the advacements in equipment and their efficiencies as well as our increased knowledge in husbandry, these temps are no longer a must and we can offer the animals we keep much more natural environments. As WarOrks15 pointed out having the proper water movement as well as open surface area for the tank and good air flow in the tank room, good O2 levels are more than possible. If you can keep a stable ph level in the 8.1-8.3 range (testing time dependant) you will not have a poor O2 level.

Higher temps do not actually increase waste production but rather increase the rate in which wastes are broken down. As far as aggression related to increased temps, I have never witnessed that myself. I actually had more problems with smaller tanks that could not be outfitted with a heater. Tanks large enough to utilize a heater for higher stable temps where IME much more stable and less prone to problems. I did however find that with the higher temps that salinity must be much more accurate though. If too much higher above 35 ppt, nuisance algaes where much more prone to being a concern. Chemistry will also come into play but that's a different topic.

Cheers
Steve

 

[pecan2phat]

Hey thanks Steve, I knew I could count on you to clarify things for me. Besides, with the temp near 79-80 degrees, there would be less of a temp swing in the summer time.

 

[KLN]

Measured with a temperature compensating refactometer, my specific gravity is 1.026 at 35 ppm salinity at 80 degrees.

 

[steve-s]

Measured with a temperature compensating refactometer, my specific gravity is 1.026 at 35 ppm salinity at 80 degrees.

That should be 35 ppt

Cheers
Steve

 

[SquishyFish]

How about a chart that shows the SPG and how it relates to temp! Would that help?

I just happen to have one!

http://www.reef-aquarium.net/resources/general/salinity.html