Rot and nano culture sg

[jbrinker]

My clowns STILL have not laid eggs again, but at least now I have a good solid nano culture, and now a decent rot culture going. My question is:

I have followed the FAF manual, and am culturing the nano and rots in 1/2 strength saltwater. (I use 1cup instant ocean per 2 gallons of water). I now realize that this will not work when transfering the rots to the larva tank, since the rots will likely die.

My question is - how do I get from here to there? I can obviously increase slowly the salinity of the rot water, but every time I add nano it will be decreasing it. Should I just raise the salinity of everything?

The other problem I see is - how do you accurately measure the sg of a nano culture? The density of the nano itself has got to affect the sg.

I do not have a refractometer...

Thanks for any advice, just want to have everything all in place for when they do lay again.

Jeff

 

[billsreef]

I like to run my cultures at the same salinity that I rear larvae. While it might be a little higher than the salinity that gives you maximum yield of rots, it's still well enough within tolerances to give you acceptable yield and it makes things easier. For measuring sg in phyto cultures, just measure it before you start the culture going. Turn over of cultures is fast enough that there will not be any significant change of sg by the time you use it.

 

[jbrinker]

OK, That's what I tried the first time around, but I crashed everything. Probably unrelated to the sg, more to my inexperience.

So, any suggestions how to get from here to there? I have 6 gallons of nice dark nano bubbling away - at half-strength salinity. Should I just calculate the necessary amount of salt-brine to bring it up to full strength and drip it in?

Same with the rots - they are currently cultured at half the salinity of the main tank (and going well). Should I slowly bring that up to full strenght?

My question as to how to measure the sg of the nano was more in relation to my current situation - I know its at half the salinity of the main tank - but if I add brine I have no way to accurately measure the result. it would have to be totally by calculation.

I guess I could try it with one gallon's worth and see if I crash it or it survives.

Thanks for any advice-
Jeff

 

[billsreef]

The nano is usually pretty resilient. However, I'd still go for bumping it slowly. What I'd do is mix up some fresh replacement media at your target SG, harvest 1/4 of your nano and replace it with the fresh media. This way you'll bump up the salinity, and not really need to worry about what the exact current SG is The rots I would drip in stages, bring them up about 10 to 15% of your target in a day.

 

[Luis A M]

I keep everything at 50%SW.Algae,rots,bs,pods,moinas,even clown larvae.
But there is no harm in suddenly increasing salinity to full SW with any of them,if needed.

 

[jbrinker]

Thanks guys. I think I will split the rot culture into at least 3, and take it from there. (One at a time for insurance).

The only reason at all Im even considering this, is that Wilkerson mentions that Rots can only take so much of a change in salinity before going into shock. I want to be able to sieve them, and just toss them into the larvae tank.

Luis, you are the first one Ive heard of raising fry at 50% of normal salinity. How do you manage the transition of the eggs/fry from full strength seawater to the lower sg of the rearing tank?

Jeff

 

[Luis A M]

<a href=showthread.php?s=&postid=13643531#post13643531 target=_blank>Originally posted</a> by jbrinker
Thanks guys. I think I will split the rot culture into at least 3, and take it from there. (One at a time for insurance).

The only reason at all Im even considering this, is that Wilkerson mentions that Rots can only take so much of a change in salinity before going into shock. I want to be able to sieve them, and just toss them into the larvae tank.

Luis, you are the first one Ive heard of raising fry at 50% of normal salinity. How do you manage the transition of the eggs/fry from full strength seawater to the lower sg of the rearing tank?

Jeff

Jeff,yes,it is rather unorthodox!
I hatch them is 1/full tank.After I get a high rot population in the tank,I begin to slowly add system full strength water.Check the effects of salinity changes in live food by yourself,they aren´t so delicate
Oh,but I missed your question,I pull the nest from normal to 50% salinity.Probably the egg shell (chorion) slows the transition.But actually,what is the salinity inside the egg and in the embryonic tissues?Somebody knows?

 

[jbrinker]

That's interesting Luis, I will have to try that method at some point. I believe I remember reading somewhere that culturing fish larvae in lower salinity water made it easier for the larvae to grow, as they have to spend less energy on maintaining osmotic balance.

Unfortunately, my rots all crashed last night... I will ask those questions in a new thread....